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ARVO 2012 Annual Meeting Abstracts 525 Contact Lens II (Basic Research) Thursday, May 10, 2012, 8:30 AM - 10:15 AM Hall B/C Poster Session Program #/Board # Range: 6076-6126/D897-D947 Organizing Section: Cornea Program Number: 6076 Poster Board Number: D897 Presentation Time: 8:30 AM - 10:15 AM Effect of Contact Lens Solutions on the Antimicrobial Efficacy of Human Tear Proteins during Lens Disinfection Bianca L. Price1A, Philip B. Morgan1B, Carole Maldonado-Codina1B, Curtis B. Dobson1A. AFaculty of Life Sciences, BEurolens Research, Faculty of Life Sciences, 1 University of Manchester, Manchester, United Kingdom. Purpose: Proteins in the tear film are deposited on and within soft contact lenses during wear. We have previously shown that proteins recovered from lenses retain their antimicrobial function, and that treatment of worn lenses with different care solutions denatures tear proteins and reduces this activity. In the present study we investigated whether the activity of ex vivo lens protein extracts is affected by the solution in which the antimicrobial assays take place. Moreover, we tested whether the potency of the tear protein antimicrobial activity is sufficient to enable it to be detected during disinfection with standard contact lens care solutions, i.e. over and above the antimicrobial activity of the biocides within those solutions. Methods: Tear proteins were extracted from worn and unworn 1-day Acuvue contact lenses with ACN/TFA. In order to assess the activity of extracted lens proteins in the presence of contact lens cleaning solutions, suspensions of Pseudomonas aeruginosa (ATCC 9027) and Staphylococcus aureus (ATCC 6538) were challenged with or without tear protein extracts in the presence of various MPS, stand-alone MPS solution components and PBS. The numbers of viable bacteria after treatment were assessed by colony counting. Results: Incubation of S. aureus and P. aeruginosa with tear proteins solubilised in PBS resulted in decreased bacterial growth. However this effect was stronger in partial MPS formulations lacking disinfectants, relative to that found in PBS. The tear protein activity was also readily detectible in the presence of fully formulated MPS, and the activity was once again stronger in full formulation MPS than that found when assays were conducted with tear proteins in PBS alone. Conclusions: These data show that tear proteins absorbed to soft contact lenses possess potent antimicrobial activity which functions synergistically with MPS and their ingredients, and which is demonstrable above and beyond the activity of fully formulated MPS. These data suggest that tear protein antimicrobial activity is important during lens disinfection and may be clinically significant. Commercial Relationships: Bianca L. Price, Bausch + Lomb (F); Philip B. Morgan, Abbott Medical Optics (R), Bausch + Lomb (F, R); Carole MaldonadoCodina, Bausch + Lomb (F, R); Curtis B. Dobson, Bausch + Lomb (F, R) Support: N/A Program Number: 6077 Poster Board Number: D898 Presentation Time: 8:30 AM - 10:15 AM Effects Of Multi-purpose Solutions On The Viability And Encystment Of Clinical Isolates Of Acanthamoeba Determined By Flow Cytometry Masaki Imayasu1, Kissaou T. Tchedre1, H D. Cavanagh2. 1R&D Center, Menicon Co Ltd, Kasugai, Japan; 2Ophthalmology, Univ Texas Southwestern Med Ctr, Dallas, TX. Purpose: The encystment process of Acanthamoeba spp is characterized by trophozoite rounding. It was reported that the incidence of Acanthamoeba keratitis (AK) in the United States was related to one specific multi-purpose solution (MPS), COMPLETE Moisture PLUS (CMP), that induced the transformation of Acanthamoeba trophozoites into resistant cyst. In this study, we simultaneously evaluated the effects of MPS on the viability and encystment of clinically isolated Acanthamoeba using flow cytometry. Methods: Viability and encystment rate were evaluated using three clinical strains of Acanthamoeba spp isolated from AK patients and Acanthamoeba castellanii (ATCC50514) when treated with four PHMB-based MPSs including CMP. Trophozoites (1.0×105) were exposed to each MPS for 24 hours. After dispensing the cell suspension into two aliquots, one aliquot was stained with 0.004% Congo Red (CR), a fluorescence dye to stain the inner cell wall of cyst, and the other aliquot was stained with a mixture of Congo Red and 1% Sarkosyl (CRS), a detergent to lyse the trophozoites and pseudo-cyst. Flow cytometric analysis of the treated aliquots was carried out on EPICS ALTRA flow cytometer. The encystment rate and disinfecting efficacies (percentage of rounded trophozoites, pseudo-cyst) were calculated by the rates of CR-stained part, CR-non-stained part and CRSstained part. Ultra-structures of resistant (mature or immature) cyst and pseudo-cyst were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results: Resistant cysts and rounded trophozoites (pseudo-cysts) were stained with CR, whereas native (unrounded) trophozoites were not. Resistant cysts were also stained with CRS unlike pseudo-cysts. No differences were found between the viabilities of clinical isolates and that of ATCC strain; however, three clinical isolates showed higher encystment rates (77.1%, 61.6%, 48.0%) than ATCC strain (43.0%) when treated with CMP. Disinfecting efficacy of each MPS was not directly related to each encystment rate. SEM and TEM observations showed basic differences in the fine structure of pseudo-cysts produced by MPSs and resistant cysts. Conclusions: It was suggested that disinfection and encystment of Acanthamoeba are independent phenomenon. Not only high encystment rate but also low disinfecting efficacies of MPS are thought to be associated with the incidence of AK. Commercial Relationships: Masaki Imayasu, Menicon Co., Ltd. (E); Kissaou T. Tchedre, Menicon Co., Ltd. (E); H. D. Cavanagh, Menicon Co., Ltd. (C) Support: None Program Number: 6078 Poster Board Number: D899 Presentation Time: 8:30 AM - 10:15 AM Evaluation Of Commercially Available Novel Multipurpose Contact Lens Care Solutions Effect On Membrane-associated Mucin Expression In The Rat Cornea Kissaou T. Tchedre1, Masaki Imayasu1, Yuichi Hori2, H D. Cavanagh3. 1R&D and Innovation Center, Menicon LTD, Kasugai, Japan; 2Ophthalmology, Toho University Sakura Medical Center, Sakura, Japan; 3Ophthalmology, Univ Texas Southwestern Med Ctr, Dallas, TX. Purpose: The purpose of this study is to determine whether commercially available new multipurpose contact lens care solutions (MPSs) have any effect on membrane-associated mucins (Muc1 & 16) expressions in the cornea using SV40 transformed Human corneal epithelial Cells (HCET) and Rat cornea. Membraneassociated mucins are one of the major components of the ocular surface that play a vital role in the maintenance of the ocular surface integrity. Methods: Human corneal epithelial cells were treated with different concentrations of MPS-F (1ppm PHMB, no boric acid), MPS-G (1.3ppm PHMB, 1ppm PQ-1, boric acid), MPS-H (1.6 ppm, Alexidine, 3ppm PQ-1, boric acid), MPS-I (1ppm PHMB, boric acid), and MPS-J (5ppm ALDOX, 10ppm PQ-1, boric acid): 100% treatment for 30 minutes and 10% treatment for 24 hours. Membrane-associated mucins (Muc 1 and Muc 16) expressions were subsequently analyzed by Western blot. Winstar Rats were also subjected to MPSs (1 drop in the right eye every 10 minutes for 1 hour). The left Eye was used as control (1 drop of PBS every 10 min for 1 hour). Cornea lysates were subsequently prepared and used for western blot analysis. Results: Western blot results showed that MPSs containing boric acid downregulate membrane-associated mucins in the cornea while MPSs without boric acid had no effect on membrane-associated mucins. Conclusions: Boric acid used in commercially available multipurpose contact lens care solutions as a buffer concentration should be chosen carefully to avoid MPSrelated ocular surface damage. Ocular surface damage simultaneously promotes microbial pathogens and potentially increases clinical rates of infection. Commercial Relationships: Kissaou T. Tchedre, Menicon (E); Masaki Imayasu, Menicon (E); Yuichi Hori, None; H. D. Cavanagh, None Support: None Program Number: 6079 Poster Board Number: D900 Presentation Time: 8:30 AM - 10:15 AM Comparison of Disinfection Efficacies of Four Contact Lens Care Regimens Against Pseudomonas aeruginosa on Orthokeratology Lenses Yoshie Itou1A, Nobuyuki Miyata1A, Tatsukata Kawagoe2, Mizuki Nobuhisa2, Eiichi Okada1. AOkada Eye Clinic, 1Okada Eye Clinic, Yokohama, Japan; 2Department of Ophthalmology and Visual Science, Yokohama City University, Yokohama, Japan. Purpose: To compare four types of contact lens care (rigid gas permeable contact lens cleaners, RGPC; hydrogen peroxide solution, H2O2; and two povidone iodine solution, for soft lenses & rigid lenses, PVP-IS & PVP-IR) in the disinfection of Pseudomonas aeruginosa from two orthokeratology lenses under experimental conditions. Methods: Emerald Lens (oprifocon A, fluorosilicone acrylate-based lens; Euclid Systems Corporation, VA) or Alfa Ortho-K Lens (fluorosilicone methacrylatebased lens; Alpha Corporation, Japan) were incubated in Brain Heart Infusion Broth (BHI; Eiken Chemical Corporation, Japan) containing 10 5 CFU/ml of Pseudomonas aeruginosa (PAO1) for 15 hours at 36 degrees Celsius to allow attachment to the lens. After incubation, lenses were either rinsed with saline (control) or cleansed by lens care solutions (RGPC: Menicon O2 Care Milfa fresh, Menicon Corporation, Japan; H2O2: AOSEPT CLEAR CARE, CIBA VISION Corporation, Japan; PVP-IS: Bioclen First Care CT, Ophtecs Corporation, Japan; PVP-IR: Bioclen O2 SEPT, Ophtecs Corporation, Japan) according to the manufacturer‟s instructions. Also, RGPC was tested in two protocols, with rubbing (following the instructions) and no rubbing. Then, lenses were soaked in BHI, and bacteria were removed by sonication and vortex mixing. The bacterial fluid was spread onto Trypto-soy agar plates (Eiken Chemical Corporation, Japan), incubated for 15 hours at 36 degrees celcius, and colonies were counted. Statistical analysis was performed by Steel-Dwass multiple comparison test. Copyright 2012 by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. For permission to reproduce any abstract, contact the ARVO Office at [email protected]. ARVO 2012 Annual Meeting Abstracts Results: The number of Pseudomonas aeruginosa attachment was higher (p<0.01) in fluorosilicone acrylate lenses (1.98 x 108 bacteria/lens) compared to fluorosilicone methacrylate lenses (6.89 x 107 bacteria/lens). All regimens significantly removed bacteria from both lenses compared to control (over 99.99% removal, p<0.01). In fluorosilicone acrylate-based lens, the numbers of remaining bacteria after care were RGPC (no rub) 2658 > RGPC (rub) 666 > PVP-IS 119 = H2O2 47 = PVP-IR 11 (p<0.05). In fluorosilicone methacrylate-based lens, the numbers of remaining bacteria after care were RGPC (no rub) 3316 > PVP-IS 42 = RGPC (rub) 35 = PVP-IR 15 = H2O2 4 (p<0.05). Conclusions: Multipurpose solution, hydrogen peroxide solution, and two types of povidone iodine solution showed significant disinfection abilities against Pseudomonas aeruginosa. Commercial Relationships: Yoshie Itou, None; Nobuyuki Miyata, None; Tatsukata Kawagoe, None; Mizuki Nobuhisa, None; Eiichi Okada, None Support: None Program Number: 6080 Poster Board Number: D901 Presentation Time: 8:30 AM - 10:15 AM Evaluation of Acanthamoeba Encystment for a Novel One-Step Hydrogen Peroxide Disinfecting Solution and Comparator Peroxide Disinfecting Solutions Shawn C. Lynch, Christopher J. Kovacs, Joseph G. Carr, Matthew A. Dehmler, Kimberly A. Millard, Michael J. Schoene, Suzanne F. Groemminger, Timothy W. Morris. Bausch & Lomb, Rochester, NY. Purpose: Acanthamoeba Keratitis (AK) is a rare, sight-threatening contact lens associated infection caused by Acanthamoeba protozoa. Withdrawal of a multipurpose lens disinfection solution in 2007 due to an association with AK has been hypothesized to be related to an encystment promoting effect of the propylene glycol demulcent. To assess the potential relevance of encystment measurements in hydrogen peroxide systems, existing peroxide disinfection systems as well as a novel demulcent-containing peroxide solution were evaluated for encystment effects. Methods: A. castellanii ATCC 50370 trophozoites were cultured in antibiotic-free AC6 medium, treated with test solutions (novel peroxide, Clear Care, AOSEPT, and Oxysept) in neutralizing lens cases for 20 - 24 hr, and evaluated for encystment using bright field and fluorescent microscopy plus Calcofluor White staining. Separately, A. castellanii trophozoites were also treated for 4, 6, or 24 hr in neutralizing lens cases and the surviving trophozoites were enumerated by axenic outgrowth plus Spearman-Karber most probable number computations to calculate log reduction values. Results: Encystment rates for all test solutions were ≤ 1.6% compared to the positive control which caused ≥ 80% trophozoite encystment. When the novel peroxide solution and the Clear Care comparator solution were tested for standalone biocidal activity against trophozoites, both solutions showed little or no recovery of live amoeba (i.e. log reduction values ranged from 3.92 to 4.34 after 4, 6, or 24 hr treatments). Also, no encystment occurred when the novel peroxide solution base formulation was tested in further dose-response experiments ranging from 0 - 3 % hydrogen peroxide. Conclusions: A novel one-step peroxide disinfecting solution and three one-step comparator peroxide solutions showed no evidence for encystment effects, suggesting that previously reported encystment effects for a MPS product are not applicable to peroxide-based solutions, regardless of the presence or absence of an ophthalmic demulcent in novel as well as in comparator peroxide solutions. Commercial Relationships: Shawn C. Lynch, Bausch & Lomb, Inc. (E); Christopher J. Kovacs, Bausch & Lomb, Inc. (E); Joseph G. Carr, Bausch & Lomb, Inc. (E); Matthew A. Dehmler, Bausch & Lomb, Inc. (E); Kimberly A. Millard, Bausch & Lomb, Inc. (E); Michael J. Schoene, Bausch & Lomb, Inc. (E); Suzanne F. Groemminger, Bausch & Lomb, Inc. (E); Timothy W. Morris, Bausch & Lomb, Inc. (E) Support: None Program Number: 6081 Poster Board Number: D902 Presentation Time: 8:30 AM - 10:15 AM Antimicrobial Properties Of Selenium Covalently Incorporated Into The Polymer Of Contact Lens Case Material Ted W. Reid1A, Phat Tran1A, Courtney Jarvis1A, Josh Thomas1A, Khiem Tran1A, Thomas Mosley2, Rob Hanes3, Abdul Hamood1B. AOphthal & Visual Science, B Microbiology, 1Texas Tech University Health Sciences Center, Lubbock, TX; 2 Selenium Ltd., Lubbock, TX; 3Selenium Ltd., Austin, TX. Purpose: Biofilm formation on contact lens cases is a serious problem since it allows bacteria to grow even in the presence of contact lens cleaning solution. Recently, silver as an antimicrobial was incorporated into contact lens cases, however, silver has several drawbacks. Any patient with silver or metal allergies cannot use these cases and silver has minimal effects against Staphylococcus aureus (S. aureus) and different fungi. In addition, silver is expensive and has to leach out of the case to be active. Thus, silver has a limited active half-life. In contrast, selenium does not have to leach out of the material to be active since it kills by the catalytic formation of superoxide radicals and it is much less expensive. Thus, this project was carried out to test the ability of selenium, covalently incorporated into the polymer of contact lens case material, to inhibit biofilm formation. Methods: Selenium monomers were made that allowed for the incorporation of selenium into the polymer of polypropylene. This material was then injection molded. The resulting material was tested for its ability to inhibit biofilm formation. S. aureus was tested since this bacteria was resistant to killing with silver. The S. aureus was allowed to grow in the presence of the polypropylene (with or without selenium) for 24 hours. The bacteria was then removed by vortexing and assayed. In one assay the bacterial concentration was determined by a colony forming unit assay (plating on agar). In another assay the bacteria was imaged by confocal laser scanning spectroscopy and then the biofilm was quantitated by COMSTAT analysis. Results: The selenium containing polypropylene showed 7.9 logs (complete) of inhibition against S. aureus and also was fully active after soaking in PBS for the equivalent of 8 weeks. Conclusions: The results showed that selenium covalently incorporated into a polypropylene polymer could total inhibit a S. aureus biofilm formation. This material could be injection molded and was still fully active after 2 months of soaking. Commercial Relationships: Ted W. Reid, Selenium Ltd. (P); Phat Tran, None; Courtney Jarvis, None; Josh Thomas, None; Khiem Tran, None; Thomas Mosley, Selenium Ltd. (E); Rob Hanes, Selenium Ltd. (E); Abdul Hamood, None Support: None Program Number: 6082 Poster Board Number: D903 Presentation Time: 8:30 AM - 10:15 AM Comparison of Biocidal Efficacy of Hydrogen Peroxide Disinfecting Systems and Total Peroxide Exposure Values Jenilee Kilbury, Kimberly A. Millard, Suzanne F. Groemminger, Erning Xia. Vision Care R&D, Bausch + Lomb Inc., Rochester, NY. Purpose: Neutralization profiles of hydrogen peroxide contact lens disinfecting solutions have been used in the past to imply antimicrobial effectiveness of hydrogen peroxide systems. Many times, only the early time points of the neutralization profile are displayed. Area Under Curve (AUC) values are determined by integration of the neutralization profile, and this method can be used to quantitate total peroxide exposure during the full recommended regimen cycle. This study sought to compare the AUC to biocidal efficacy of four hydrogen peroxide disinfecting systems. The solutions evaluated included high and low AUC models, and control products utilizing either a catalytic disk or a catalase tablet for neutralization. Methods: Neutralization profiles were measured for each of the four solutions by determining the change in hydrogen peroxide concentration over time. Peroxide concentrations were measured at specified time points throughout a 6 hour neutralization time using a standard redox titration method. The two model formulations were neutralized using contact lens cases containing catalytic disks. The two control products were neutralized according to the manufacturers prescribed regimens. Biocidal efficacy was determined by ISO/FDA Stand Alone Procedure for Disinfecting Products. Results: The AUC values of the four formulations at the end of the test time period varied from 6000-16000 ppm*hr. For the most difficult organisms to kill, yeast and fungi, the total log kill directly correlated to the AUC for each of the systems. The results of yeast and fungi reduction varied from <1 log for the lowest AUC model to > 3 logs for the highest model. In terms of the bacteria, all systems demonstrated 99.99% kill after 6 hours, however the time required for this level of effectiveness varied depending on the bacteria, from 15 minutes to 6 hours. Conclusions: The Area Under Curve (AUC) value of a hydrogen peroxide contact lens disinfecting system is a quantitative assessment of the total peroxide exposure available to kill microorganisms. The AUC values can be used as an indicator of biocidal efficacy of the solution, particularly against yeast and fungi. Higher AUC values indicate a better overall kill against all organisms tested using this method. Commercial Relationships: Jenilee Kilbury, Bausch + Lomb Inc. (E); Kimberly A. Millard, Bausch + Lomb Inc. (E); Suzanne F. Groemminger, Bausch + Lomb Inc. (E); Erning Xia, Bausch + Lomb Inc. (E) Support: None Program Number: 6083 Poster Board Number: D904 Presentation Time: 8:30 AM - 10:15 AM Regimen Testing of a Novel One-Step Hydrogen Peroxide Disinfecting Solution and Comparators with Soft Contact Lenses and Ocular Clinical Isolates Jessica M. Burger, Todd H. Bassage, Arthur J. Principe, Deborah McGrath, Patricia A. Walsh, Timothy W. Morris. Microbiology, Bausch & Lomb, Inc., Rochester, NY. Purpose: To evaluate a novel one-step hydrogen peroxide disinfecting solution and one-step peroxide comparator solutions for performance in regimen testing Copyright 2012 by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. For permission to reproduce any abstract, contact the ARVO Office at [email protected]. ARVO 2012 Annual Meeting Abstracts conducted with representative soft contact lenses and recent clinical ocular isolates of pathogenic bacteria and fungi. Methods: A novel one-step hydrogen peroxide disinfecting solution along with Clear Care and Oxysept comparators were all tested in recommended companion peroxide neutralizing lens cases for each solution. Regimen test methods were based upon the ISO 14729 test standard for disinfecting products modified to permit testing of both hospital-acquired (HA) and community-acquired (CA) methicillin-resistant Staphylococcus aureus (MRSA), quinolone-resistant Pseudomonas aeruginosa (QRPA), Stenotrophomonas maltophilia, Candida albicans, and Fusarium solani. SofLens 38 (polymacon), Acuvue 2 (etafilcon A), or Acuvue Oasys (senofilcon A) lenses were inoculated with ~ 5 x 10 5 CFU of each microbe suspended in 100% organic soil, transferred to lens cases, rinsed per recommended instructions, and soaked for 4 and 6 hr. Inoculated lenses and soak solutions were then filtered and plated by validated methods to recover surviving microbes. Results: All three peroxide solutions showed little or no recovery of surviving cells for all four bacterial strains or the F. solani mold at either 4 or 6 hr time points, with mean recoveries for all solution/lens/microbe combinations ranging from 0.0 6.8 CFU. For the C. albicans yeast clinical isolate, 0.0 - 3.3 mean CFU were recovered from the novel peroxide and Clear Care treatments, while 3.0 - 13.8 mean CFU were recovered from Oxysept treatments. Conclusions: The results indicate that all three one-step peroxide disinfection systems substantially remove recent ocular clinical isolates of bacteria and fungi from soft contact lenses in vitro, although Oxysept showed slightly less activity than the novel peroxide and Clear Care systems against the C. albicans yeast clinical isolate. Commercial Relationships: Jessica M. Burger, Bausch & Lomb, Inc. (E); Todd H. Bassage, Bausch & Lomb, Inc. (E); Arthur J. Principe, Bausch & Lomb, Inc. (E); Deborah McGrath, Bausch & Lomb, Inc. (E); Patricia A. Walsh, Bausch & Lomb, Inc. (E); Timothy W. Morris, Bausch & Lomb, Inc. (E) Support: None Program Number: 6084 Poster Board Number: D905 Presentation Time: 8:30 AM - 10:15 AM Pharmacodynamic Analysis of Hydrogen Peroxide Solution Disinfection Efficacy in One-Step Peroxide Neutralizing Lens Cases Timothy W. Morris, Damien W. Cordero, Deborah McGrath, Suzanne F. Groemminger, Kimberly A. Millard. Bausch & Lomb, Inc, Rochester, NY. Purpose: Previous pharmacodynamic studies have demonstrated clear quantitative relationships between total hydrogen peroxide exposures (expressed as ppm peroxide x hr of exposure) and microbial killing (expressed as log reduction values) for ISO/FDA specified bacteria, yeast, and mold tested at constant peroxide concentrations in test tubes. Here, pharmacodynamic analysis was used to instead evaluate efficacy of a model one-step peroxide lens disinfection system wherein microbial killing and peroxide neutralization occur simultaneously in lens cases containing platinum neutralizing disks. Methods: A series of phosphate buffered solutions (pH 6.5, ~250 mOsm) containing 1.0 - 5.0 % peroxide (10,000 - 50,000 ppm) were challenged with Serratia marcescens (Sm) prepared in 10% organic soil in one-step neutralizing lens cases per the ISO 14729 standard for disinfection efficacy testing. Inoculated lens cases were sampled at 10, 20, 30, 60, and 120 min for parallel enumeration of surviving bacteria (to determine log reduction values) plus colorimetric redox titrations of residual peroxide concentrations (to determine total peroxide exposures as ppm x hr). Results: Sm log reduction values ranged from 0.0 for 10 min treatment with initial 1.0% peroxide to >4.8 for any treatment ≥ 10 min with initial 5.0% peroxide. Corresponding total peroxide exposures ranged from 1,168 - 7,609 ppm x hr. For all time points, complete killing (i.e. >4.8 log reduction) required ~5,000 ppm x hr, intermediate killing (i.e. 3.4 log reduction) required ~3,700 - 4,300 ppm x hr, and reduced killing (i.e. 1.6 - 1.8 log reduction) required ~2,400 - 2,800 ppm x hr peroxide exposures. The R2 curve fit value for measured peroxide exposures versus Sm log reductions in lens cases was 0.98. Conclusions: Pharmacodynamic analysis of Sm killing conducted in one-step peroxide neutralizing lens cases demonstrates that there remains a clear quantitative relationship between total hydrogen peroxide exposures and microbial killing, even when microbial killing and neutralization of active peroxide occur simultaneously. For Sm in lens cases, short treatments with high peroxide concentrations are quantitatively equivalent to longer treatments with lower peroxide concentrations. Commercial Relationships: Timothy W. Morris, Bausch & Lomb Inc. (E); Damien W. Cordero, Bausch & Lomb Inc. (E); Deborah McGrath, Bausch & Lomb Inc. (E); Suzanne F. Groemminger, Bausch & Lomb Inc. (E); Kimberly A. Millard, Bausch & Lomb Inc. (E) Support: None Program Number: 6085 Poster Board Number: D906 Presentation Time: 8:30 AM - 10:15 AM Antimicrobial Efficacy of Melimine Covalently Bound to Contact Lenses Debarun Dutta1,2, Nerida Cole1,2, Mark Willcox1,2. 1Brien Holden Vision Institute, Sydney, Australia; 2School of Optometry and Vision Science, University of New South Wales, Sydney, Australia. Purpose: There remains a need to reduce microbial contamination of contact lenses, and thus the rate of adverse events during wear. The purpose of the current study was to evaluate antimicrobial efficacy of melimine, a synthetic cationic peptide, against drug resistant and biofilm producer strains of Pseudomonas aeruginosa and Staphylococcus aureus when covalently bound to contact lenses. Methods: Melimine was covalently incorporated into an Etafilcon A contact lens. The amount of peptide present on the lens surface was quantified using dye adsorption. Antimicrobial activity against the bacterial strains was evaluated by measuring the amount of cell death compared to control lenses with no melimine. High salt treatment (10% NaCl) was carried out to extract any adsorbed peptide to ensure that the activity was only due to bound melamine. The stability of the bound peptide to autoclaving at 120ºC for 15 minutes was measured. Results: There was 7.4 ± 0.7 µg of melimine present on the lens surface. High salt treatment significantly (p<0.05) reduced the amount of adsorbed melimine but affect the antimicrobial activity by only 0.1 to 0.2 log. There remained good activity after salt treatment, with contact lenses showing 3.1 log reduction against P. aeruginosa strain 6294 and 3.9 log inhibition against S. aureus strain 31. There were negligible (0.2 to 0.3 log) reductions of antimicrobial activity after heat sterilization. Covalently bound melimine was active against multidrug resistant S. aureus strains 060 and 110, and P. aeruginosa 037, as well as against the strong biofilm producer P. aeruginosa 142, giving 2.4 log, 2.3 log, 4.1 log and 3.4 log reductions in bacterial counts respectively. Conclusions: Melimine may offer excellent potential for development as a broad spectrum antimicrobial coating for contact lenses, showing strong activity against both gram negative and gram positive organisms which are resistant to antibiotics. The coating is heat stable and thus has the potential to be developed further. Commercial Relationships: Debarun Dutta, None; Nerida Cole, None; Mark Willcox, None Support: University International Postgraduate Award (UIPA), UNSW and by the Brien Holden Vision Institute through a postgraduate grant to cover facilities Program Number: 6086 Poster Board Number: D907 Presentation Time: 8:30 AM - 10:15 AM Organo-Selenium Coated Contact Lenses: Effect Upon Bacterial Biofilm Attachment Phat Tran1A, Abdul Hamood1B, Courtney Jarvis1C, Josh Thomas1C, Blake Lackey1C, Thomas Mosley2, Ted Reid1C. AOphthalmology and Visual Sciences, B Microbiology, COphthalmology, 1Texas Tech University Health Sciences Center, Lubbock, TX; 2Selenium Ltd., Lubbock, TX. Purpose: Bacterial biofilm on contact lenses has been cited as a possible cause of corneal infection and acute red eye. A contact lens coating that blocks biofilm formation might reduce the frequency of these clinically significant problems. Selenium compounds can catalyze the formation of superoxide radicals in the tear film, which are cytotoxic to bacteria. Thus, this study investigated the effectiveness of a covalent organo-selenium coating on polyHEMA (Acuvue2) contact lenses. Methods: The contact lenses were coated with organo-selenium compounds via wet chemistry covalent bond formation. The inhibition of biofilm formation with the organo-selenium coating was investigated by incubating organo-selenium coated and uncoated contact lenses in a nutrient broth containing, either Pseudomonas aeruginosa, Serratia marcescens or Staphylococcus aureus for 24 hours at 37oC. Biofilms were quantified by determining the CFU per lens. To determine the CFU/lens, each lens was gently rinsed with sterile distilled H2O, and placed into a microcentrifuge tube containing 1 ml phosphate buffered saline (PBS), and then vigorously vortexed three times for 1 min vortex to detach the cells. Suspended cells were serially diluted 10-fold in PBS and 10-μl aliquots of each dilution were spotted on LB agar plates. The plates were incubated at 37oC for 24 hours and the CFU were counted. For confocal laser scanning microscopy (CLSM), we used the S. aureus strain AH1333 and the P. aeruginosa strain PAO1GFP strains. Both strains carry the gene that encodes the green fluorescent protein. For scanning election microscopy (SEM), the lenses were fixed in 3% glutaraldehyde and then imaged. Results: Colony forming unit assays showed total inhibition, representing over 6 logs of bacterial killing on contact lenses coated with organo-selenium compounds. Scanning election microscopy and confocal laser scanning microscopy confirmed these results. Conclusions: The organo-selenium coating successfully blocked the formation of a bacterial biofilm on the polyHEMA (Acuvue2) contact lenses for Pseudomonas aeruginosa, Serratia marcescens and Staphylococcus aureus in vitro. Commercial Relationships: Phat Tran, None; Abdul Hamood, None; Courtney Jarvis, None; Josh Thomas, None; Blake Lackey, None; Thomas Mosley, Selenium Ltd. (E); Ted Reid, Selenium Ltd. (I, P) Support: None Copyright 2012 by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. For permission to reproduce any abstract, contact the ARVO Office at [email protected]. ARVO 2012 Annual Meeting Abstracts Program Number: 6087 Poster Board Number: D908 Presentation Time: 8:30 AM - 10:15 AM Non-Cultivatable Bacterial Biofilm Communities in Used Contact Lens Cases Judith L. Flanagan1, Martin Allgeier2, Mark D. Willcox3, Philip Hugenholtz4. 1 Brien Holden Vision Institute, Sydney, Australia; 2Joint Genome Institute, Walnut Creek, CA; 3Brien Holden Vision Institute, Univ of New South Wales, Sydney, Australia; 4Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences & Institute for Mol, University of Queensland, Queensland, Australia. Purpose: Using phylogentic modeling, we sought to document the microbial ecology of contaminating biofilms in used contact lens cases as the first step in an effort to determine how these communities contribute to, or help to protect against, adverse ocular events such as corneal infiltrative events (CIEs). Methods: Lens cases from subjects (and control cases) were swabbed with PBS (100 µl). DNA was extracted using Wizard Genomic DNA Isolation System (Promega, CA, USA). SSU rRNA was amplified (35 cycles PCR) using primers 926F and 1392R with barcodes and 454 linker. Pyrosquencing was performed using 454 titanium technology. Raw sequence reads were analysed using software pyrotaggers followed by custom analysis. Results: 6000 independent reads were generated from each lens case and indicated a high microbial diversity including the presence of phyla previously implicated in MK such as Propionibacterium, Staphylococcus, Streptococcus, Gammaproteobacteria (including Stenotrophomonads, Pseudomonads), and Tsukamurella. Shannon‟s diversity index (SDI) which typically ranges from 1.5 (low species richness and evenness) to 3.5 (high species evenness and richness) indicated high diversity in the used contact lens cases (3.853 and 2.840), similar to that found on human skin in which most sequences are assigned to 4 phyla: Actinobacter, Firmicutes, Proteobacteria and Bacteroidetes. Most abundant phyla in the lens cases were α- and γ-Proteobacteria, Firmicutes and Actinobacter. These commensal profiles differ markedly from bacteria detected by culture from asymptomatic subjects. Conclusions: This pilot study provided evidence of very high microbial diversity in used contact lens cases of healthy wearers. Whether these commensal bacteria offer some protection against infection needs to be addressed through a larger temporal study in which bacterial community dynamics can be monitored for both healthy wearers and wearers who suffer a CIE. Commercial Relationships: Judith L. Flanagan, None; Martin Allgeier, None; Mark D. Willcox, None; Philip Hugenholtz, None Support: None Program Number: 6088 Poster Board Number: D909 Presentation Time: 8:30 AM - 10:15 AM Evaluation of Antimicrobial Activity and Cytotoxicity of Diamidine as a Disinfectant Bandarage M. Bandara, Rani S. Bandara, Duojia Wu, Hua Zhu, Sylvie Franz, Mark D. Willcox. Brien Holden Vision Institute, UNSW, Sydney, Australia. Purpose: Aromatic diamidines have been demonstrated to be active against different pathogens, such as bacteria, fungi and protozoa. The purpose of this study was to evaluate the antimicrobial activity and cytotoxicity of diamidine in combination with polyhexamethylene biguanide (PHMB). Methods: Antimicrobial activity of a solution containing diamidine and PHMB was evaluated according to the stand-alone test for contact lens disinfection products described by ISO 14729 (2001). ATCC strains of Serratia marcescens 13880, Staphylococcus aureus 6538, Pseudomonas aeruginosa 9027, F. solani 36031 and Candida albicans 10231 were used to challenge the test solutions. Phosphate buffered saline was used as a control. After disinfection at 25°C for 6 hours, the numbers of viable microorganisms in the samples were determined and the average log reductions in test samples for each strain were calculated. The solutions were also challenged with trophozoites of Acanthamoeba polyphaga ROS and Acanthamoeba castellani 044, and the number of survivors were determined following 7 days of incubation at 32º C. Cytotoxicity of the solutions were examined using agar overlay and acute ocular irritation assays according to ISO 10993-5 and 10993-10 standards respectively. Results: Diamidine in combination with PHMB demonstrated complete kill of S. marcescens, S. aureus, and P. aeruginosa (i.e. > 7 logs), and displayed 5.1 ± 0.5 or 2.4 ± 0.8 log reductions against C. albicans or F. solani respectively after 6 hours of disinfection. Further, the combination of diamidine and PHMB also displayed 3.0 and 2.6 log reductions against trophozoites of A. polyphaga and A. castellanii respectively after 6 hours of disinfection. Both agar overlay and acute ocular irritation assays showed no toxic effect of the combination of diamidine and PHMB. Conclusions: The results have demonstrated that a combination of diamidine and PHMB is effective against various microorganisms. The combination was not toxic. This combination may be useful in development of safe and effective disinfection solutions for soft contact lenses. Commercial Relationships: Bandarage M. Bandara, None; Rani S. Bandara, None; Duojia Wu, None; Hua Zhu, None; Sylvie Franz, None; Mark D. Willcox, None Support: None Program Number: 6089 Poster Board Number: D910 Presentation Time: 8:30 AM - 10:15 AM Membrane Permeability Of Staphylococcus Aureus Aggregates Exposed To Contact Lens Care Solutions David J. McCanna, Lyndon W. Jones. CCLR-School of Optometry, University of Waterloo, Waterloo, ON, Canada. Purpose: Microbial keratitis and corneal infiltrates have been associated with the development of bacterial aggregates (biofilms) on the surface of contact lens cases. Contact lens case contamination with biofilms occurs often due to the resistance of the bacterial aggregates to the antimicrobials present in contact lens care solutions. This study investigated the ability of contact lens care solutions to damage the cell membranes of Staphylococcus aureus (SA) aggregates. Methods: Staphylococcus aggregates were formed by growing the bacteria on Mueller-Hinton Agar, harvesting with physiological saline and washing using centrifugation (500 x g for 5 minutes). Commercial contact lens solutions evaluated contained the antimicrobials polyquaternium-1 (PQ1) and polyhexamethylene biguanide (PHMB), PHMB alone, PQ1 and alexidine (ALX), and PQ1 and ALDOX. Each solution was challenged with 5 x 10(7)cfu/ml of SA (ATCC 6538) for 4 hours. After exposure, the bacteria were stained with SYTO 9 and propidium iodide (PI). Using a confocal microscope with a 488nm laser and the appropriate emission filters for these two dyes, the number of cells with damaged cell membranes was determined. Results: The contact lens solution that caused the greatest damage to the SA cell membranes was the formulation based on PQ1-ALX, with 81% of all cells being permeable to PI. The other formulations caused some of the bacteria to lose membrane integrity (13 - 30%), but did not cause as much damage to the bacteria cell membranes (all p < 0.05) as the PQ1-ALX formulation. Conclusions: One of the five lens care systems tested caused a substantial number of SA bacteria to lose membrane integrity. Although membrane damage is only one of the many mechanisms by which an antimicrobial can kill microorganisms, understanding the ability of contact lens care solutions to damage bacteria cell membranes in an aggregate formation could lead to improved formulations for eradicating biofilms from contact lens cases. Commercial Relationships: David J. McCanna, None; Lyndon W. Jones, None Support: None Program Number: 6090 Poster Board Number: D911 Presentation Time: 8:30 AM - 10:15 AM Comparison Of Two Dual-disinfection Systems For Ocular Comfort, Corneal Staining And Corneal Infiltrative Events Daniel Tilia1, Percy Lazon De La Jara1,2, Nikki Peng1, Hua Zhu1, Mark D. Willcox1,2, Brien A. Holden3,2. 1Brien Holden Vision Institute, Sydney, Australia; 2 School of Optometry and Vision Science, University of NSW, Sydney, Australia; 3 Brien Holden Vision Institute, Vision Cooperative Research Centre, Sydney, Australia. Purpose: To retrospectively compare ocular comfort ratings, corneal staining, and the incidence of solution induced corneal staining (SICS) and corneal infiltrative event (CIE) between two lens care products (LCPs) when used with a silicone hydrogel contact lens Methods: Ocular comfort ratings and corneal staining, SICS and CIE incidence were extracted retrospectively from two prospective, unmasked studies involving 79 participants wearing balafilcon A (PureVision®, Bausch + Lomb, USA) and using one of two LCPs; RevitaLens OcuTec® multipurpose disinfecting solution (MPDS) (alexidine dihydrochloride and polyquaternium-1, Abbott Medical Optics, Inc. USA) or Biotrue™ multipurpose solution (MPS) (PHMB and polyquaternium1, Bausch + Lomb, USA). Each study followed the same protocol Visits were at baseline, two weeks, one month and three months. Comfort (1-10 scale) and corneal staining (0-4 grade) were compared between LCPs using linear mixed model. SICS and CIEs were reported as the first occurrence per 100 participantmonths for each LCP and compared using Fisher‟s exact test and mid-p test for incidence rates Results: There were no significant differences between RevitaLens OcuTec MPDS and Biotrue MPS for comfort on insertion (7.6±1.6 v 8.0±1.5, p>0.05), comfort during the day (8.1±1.4 v 7.8±1.5, p>0.05) or end of the day comfort (7.0±1.7 v 6.8±1.7, p>0.05). Corneal staining was significantly less with RevitaLens OcuTec compared to Biotrue (0.7±0.6 v 1.8±0.8, p<0.001). SICS incidence was also significantly lower with RevitaLens OcuTec compared to Biotrue (5.1% v 29.0%, p<0.001), while there was no significant difference between LCPs for CIE incidence (0 v 1.8%, p>0.05). Conclusions: The PHMB/polyquat containing Biotrue MPS produced more SICS than the alexidine/polyquat containing RevitaLens OcuTec MPDS. Similar ocular comfort observed between the LCPs might be due to using the same contact lens type and the low CIE incidence indicates both LCPs are effective in controlling lens/case contamination. Commercial Relationships: Daniel Tilia, Abbott Medical Optics, Inc. (F); Percy Lazon De La Jara, Abbott Medical Optics, Inc. (F); Nikki Peng, Abbott Medical Optics, Inc. (F); Hua Zhu, Abbott Medical Optics, Inc. (F); Mark D. Willcox, Abbott Medical Optics, Inc. (F); Brien A. Holden, Abbott Medical Optics, Inc. (F) Copyright 2012 by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. For permission to reproduce any abstract, contact the ARVO Office at [email protected]. ARVO 2012 Annual Meeting Abstracts Support: None Clinical Trial: http://www.anzctr.org.au, ACTRN12610001068055 Program Number: 6091 Poster Board Number: D912 Presentation Time: 8:30 AM - 10:15 AM Ocular Cytotoxic Potential Assessment Of Contact Lens Care Solutions And Evidence For A Useful Rinse Step With Unpreserved Solution Melody Dutot1A, Jacques VINCENT2, Isabelle FABRE2, Christine GRASMICK2, Roxane Fagon1B, Patrice Rat3. AToxicology, BResearch&Development, 1YSLAB, Paris, France; 2Direction des Laboratoires et des Contrôles, Agence Française de Sécurité Sanitaire des Produits de Santé, Vendargues, France; 3Chimie-Toxicologie Analytique et Cellulaire (EA 4463), Université Paris Descartes, Sorbonne Paris Cité, Faculté de Pharmacie, Paris, France. Purpose: Contact lens care solutions are known to have toxic effects for the ocular surface. The evaluation of in vitro toxicity of contact lens care solutions is required because of its predictive value for ocular irritation in humans. ISO 10993-5 standard assesses medical devices (such as contact lens care solutions) biocompatibility through the evaluation of necrosis but needs some adjustments to better discriminate multipurpose solutions. The aim of our study was double: first, to run an interlaboratory study with French medical agency to propose adapted tools to study contact lens care solutions cytotoxicity, and second to evaluate the interest of adding a rinse step in contact lens cleaning procedure as a protection against contact lens care solutions cytotoxicity. Methods: In the first place, conjunctival cells (human WKD cell line) were exposed for 30 minutes and 1 hour to neat contact lens care solutions (Optifree, Alcon; Boston Simplus, Bausch-Lomb; Renu, Bausch-Lomb; and Menicare Plus, Menicon). Cell viability was assessed using the neutral red and the alamar blue tests, and benzalkonium chloride was used as a positive control. In the second place, corneal cells (human HCE cell line) were exposed for 24 hours to contact lenses (Acuvue Advance, Johnson&Johnson and Proclear, Cooper Vision) previously soaked in 100mL contact lens care solutions (Optifree, Alcon; Biotrue, Bausch-Lomb; and Renu, Bausch-Lomb) for 96 hours according to 1994 FDA Premarket Notification 510(k) Guidance Document for Daily Wear Contact Lenses and rinsed with a marine ionic solution (Lacrymer, Yslab, France). Results: Optifree and Menicare Plus induced a loss of cell viability: 26% of living cells according to neutral red assay and 49% of living cells according to alamar blue assay for Optifree, 42% of living cells according to neutral red assay and 76% of living cells according to alamar blue assay for Menicare Plus. Optifree, the most cytotoxic multipurpose solution, was also adsorbed on both Acuvue Advance and Proclear contact lenses and released on corneal cells. This release from Acuvue Advance and Proclear induced a decrease in cell viability of 55% and 36%, respectively. Optifree cytotoxicity was totally abolished when a rinse step with Lacrymer was added to the cleaning procedure. Conclusions: ISO 10993-5 standard could be improved for the evaluation of contact lens care solutions: the cell line, the incubation time and the solutions dilution have to be adapted to the ocular surface field to better discriminate contact lens care solutions. Among the four contact lens care solutions tested, two were highly cytotoxic. This cytotoxicity could be avoided by a rinse step with unpreserved marine ionic solution. Commercial Relationships: Melody Dutot, Yslab (E); Jacques Vincent, None; Isabelle Fabre, None; Christine Grasmick, None; Roxane Fagon, Yslab (E); Patrice Rat, None Support: None dispensed with silicone hydrogel lenses (lotrafilcon A, CIBA VISION, USA) on a 30-night overnight wear schedule. Clinic visits were conducted at 1 week, 1 month and 3 months. Results: Logistic regression analysis showed a reduced risk of mechanical events (corneal erosion, superior epithelial arcuate lesion, contact lens papillary conjunctivitis) with morning lens replacement (0.8%, p = 0.013 [1 month]) and morning lens cleaning (1.0%, p = 0.031 [1 month] and p = 0.042 [3 months]) compared to nightly lens replacement (3.4%) and monthly lens replacement (5.2%). These mechanical events were driven primarily by corneal erosions, the incidence of which was 0.6% for morning lens replacement, 0.5% for morning lens cleaning, 3.4% for nightly lens replacement and 3.1% for monthly lens replacement. Conclusions: Continuous contact lens wear related ocular mechanical adverse events can be reduced by changes in cleaning or replacement modality and such changes may be related to elimination of the overnight „debris accumulation‟ with a morning replacement / cleaning modality. Commercial Relationships: Jerome Ozkan, None; Mark D. Willcox, None; Percy Lazon De La Jara, None; Varsha M. Rathi, None; Brien A. Holden, None Support: None Clinical Trial: http://www.anzctr.org.au, ACTRN12610000336088 Program Number: 6093 Poster Board Number: D914 Presentation Time: 8:30 AM - 10:15 AM Qualitative and Quantitative Lubricity of Experimental Contact Lenses Robert C. Tucker, Brad Quinter, Dharmesh Patel, John Pruitt, Jared Nelson. R&D, Alcon, Johns Creek, GA. Purpose: Surface lubricity plays an important role in biomedical device comfort by reducing stresses on tissue. A qualitative manual (finger) rubbing lubricity and a quantitative inclined plane method have been developed to describe contact lens lubricity and friction. Methods: Experimental contact lenses with four different surface chemistries were developed. Four lenses of each group were evaluated with qualitative manual rubbing and quantitative inclined plane methods after overnight phosphate buffered saline (PBS) soaking to remove any package saline additives. To determine manual (finger) lubricity values, the lenses were rubbed between the thumb and index finger for approximately 20 seconds. The lenses were ranked according to their lubricity value from LV0 (best) to LV4 (worst). These values are found to be inversely proportional to the crosslink density. The lubricity values were repeatable in a blind test. For the inclined plane, a clean glass plate is adjusted to the desired angle in a PBS bath. The lens of interest is placed at the top of the glass plate, and a 0.8 g weight is placed on the lens to initiate movement. A minimum critical angle is determined, which just maintains lens movement over a distance of approximately 100 mm. The tangent of the critical angle is the critical coefficient of kinetic friction (CCOF). These values were compared with a lotrafilcon B control. Results: Different experimental surface chemistries (on the same core lens material) were able to be categorized repeatedly with distinct manual lubricity values (LV, shown in figure 1). The kinetic coefficient of friction as measured by the inclined plane method (CCOF) showed an increase in CCOF consistent with the manual lubricity values. The experimental groups had a lower average CCOF than the control lens (n=4, p<0.05), which has a different core and surface chemistry. Conclusions: Two novel techniques (manual lubricity and inclined plane) have been evaluated to rate and quantify the lubricity of contact lenses. This method allows contact lens lubricity to be optimized by adjusting surface chemistry for Program Number: 6092 Poster Board Number: D913 Presentation Time: 8:30 AM - 10:15 AM Morning Cleaning or Replacement of Lenses Reduces Complications with Extended Wear of Contact Lenses Jerome Ozkan1A, Mark D. Willcox2, Percy Lazon De La Jara1, Varsha M. Rathi3, Brien A. Holden4. AClinical Research & Trials Centre, 1Brien Holden Vision Institute, Sydney, Australia; 2Brien Holden Vision Institute, Univ of New South Wales, Sydney, Australia; 3Cornea, Contact lens, Refractive Surgery, LV Prasad Eye Institute, Banjara Hills, Hyderabad, India; 4Brien Holden Vision Institute, Vision Cooperative Research Centre, Sydney, Australia. Purpose: A previous study has shown that the rate of microbial keratitis is comparable to the rate corneal erosions coupled with gram negative contamination of lenses. A retrospective analysis was conducted to determine if cleaning or replacing lenses in the morning or evening, during continuous wear, influenced the rate of corneal erosions. Methods: Previously conducted continuous wear studies at the same site consisted of: morning lens replacement study (n=87) and evening lens replacement study (n=90) where subjects discarded worn lenses and replaced with a new lens each morning or night, respectively; morning lens cleaning study (n=100) where subjects removed and cleaned lenses with a commercial multipurpose solution (COMPLETE® Easy Rub™, Abbott Medical Optics, USA) and immediately reinserted the lenses. The historical control was monthly lens replacement (n = 95) where lenses were worn for one month and then discarded. All subjects were Copyright 2012 by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. For permission to reproduce any abstract, contact the ARVO Office at [email protected]. ARVO 2012 Annual Meeting Abstracts improved on-eye performance. *Fagehi R, Tomlinson A, Manahilov V. ARVO 2011 E-abstract: 6524, 2011. Commercial Relationships: Raied Fagehi, None; Alan Tomlinson, None; Velitchko Manahilov, None Support: None Commercial Relationships: Robert C. Tucker, Alcon (E); Brad Quinter, Alcon (E); Dharmesh Patel, Alcon (E); John Pruitt, Alcon (E); Jared Nelson, Alcon (E) Support: None Program Number: 6094 Poster Board Number: D915 Presentation Time: 8:30 AM - 10:15 AM Effect of Soft Contact Lens Storage Solutions on Lens Wettability In-Vitro Raied Fagehi, Alan Tomlinson, Velitchko Manahilov. Vision Sciences, Glasgow Caledonian University, Glasgow, United Kingdom. Purpose: Developments in soft contact lens (SCL) polymers and multi-purpose storage solutions (MPS) have improved biocompatibility of lens surfaces. This study investigated in-vitro effects of MPS on SCLs wettability. Methods: A camera connected to a Doane interferometer captured images of prelens fluid films on 4 SCLs; ACUVUE ADVANCE and 1-DAY MOIST (Johnson & Johnson); AIR OPTIX and DAILIES (CibaVision). Wettability was measured direct from the pack, then after 8 and 48 hours storage in 5 MPS: OPTI-FREE EverMoist and Express (Alcon), COMPLETE MPS (AMO), ReNu Multiplus (Bausch & Lomb) and SOLO-care AQUA (CibaVision). Six recordings of complete drying of each SCL were analysed by a MATLAB programme. Four previously described parameters of wettability were assessed: onset latency (OL), the time to first break-up; drying duration (DD), the duration of drying after first break-up; the maximum speed of drying (MS); and the time to reach this maximum speed (PL).* Results: Effective parameters of wettability were DD, PL and MS; DD being the primary (independent) measure. Univariate factor analysis revealed significant main effects of lens polymer (for DD, F = 284.1, p<0.001), MPS (F = 216.4 p<0.001), and storage time (F = 203.3 p<0.001); a significant interaction was found between these factors (F=22.3 p< 0.001).Blister pack solutions for most lenses produced similar results; AIR OPTIX solution gave better initial wettability. Storage in MPS produced benefit after 8 hours, but varied with MPS and SCL (Figure 1). The effect was similar for SOLO-care and COMPLETE across all lenses but significant wetting benefits were seen for EverMoist and ReNu with the AIR OPTIX and DAILIES lenses and for Express with AIR OPTIX and 1-DAY MOIST lenses. Conclusions: Interactions effects on wettability between SCLs and the MPS suggest that in prescribing some lenses, specific storage solutions should be recommended. Program Number: 6095 Poster Board Number: D916 Presentation Time: 8:30 AM - 10:15 AM Robust Contact Lens Lubricity using Surface Gels W. G. Sawyer1, Alison C. Dunn1, Juan M. Uruena1, Howard A. Ketelson2. 1 Mechanical and Aerospace Eng, University of Florida, Gainesville, FL; 2R & D, Alcon Research Ltd, Fort Worth, TX. Purpose: To determine the effects of a soft surface gel on the lubricity of contact lenses. This study examines the friction response of the gel layer under varied pressures and correlates the frictional behavior and frictional responses to the mechanical properties of the gel layer. Methods: Gradient gel surfaces (2-3 um thick) were formed on the surfaces of a new type of silicone hydrogel daily disposable contact lens (DAILIES TOTAL1®). These layers were minimally crosslinked and enveloped the entire lens. Friction measurements were carried out on a precise micro-tribometer constructed specifically to probe low contact pressure sliding in aqueous environments. This apparatus can reliably perform experiments at contact pressures approaching 1 kPa, and can go up to pressures in excess of those seen on the human eye during ocular movements and blinking. Experimental soft contact lenses (20) were mounted into a custom conformal holder, placed in a bath of borate-buffered saline (Unisol®), and heated to physiological temperatures. Lubricity experiments were performed at a range of contact pressures (1-10kPa) and sliding speeds (10um/s - 600um/s). Results: This gel layer was designed to enhance lubricity and comfort of the contact lenses by acting as a compliant foundation to spread contact, reduce pressure, and promote boundary lubrication. Contact mechanics experiments and indentation reveals that the gels have a low elastic modulus (<200KPa), and at contact pressures below 18 kPa the friction coefficients are mu=0.03. The friction coefficient is robust to pressure changes under the 18 KPa pressure threshold and does not show any effect of sliding speed over the range examined. Conclusions: Tribological probing of the surface gels indicates that they are compliant but mechanically stable to pressures below 18 KPa. At pressures such as those seen in the eye (3-5 kPa) the gel layers can support smooth sliding and provide a lubricous surface with friction coefficients of mu=0.03 in the boundary lubrication regime. These findings indicate that surface gels can be a route to promote lubricity in contact lenses. Commercial Relationships: W. G. Sawyer, None; Alison C. Dunn, None; Juan M. Uruena, None; Howard A. Ketelson, Alcon (E) Support: Alcon Research, Ltd. Program Number: 6096 Poster Board Number: D917 Presentation Time: 8:30 AM - 10:15 AM Improving The Wettability Of Silicone Hydrogel Contact Lenses Alonzo Cook, Matthew Skinner, Jun Li, Christopher Loose, Karen Schultz, Zheng Zhang. Semprus BioSciences, Cambridge, MA. Purpose: We have developed stable, extremely hydrophilic polymers that reduce fouling and improve surface wettability on medical devices. Recently, this polybetaine chemistry was applied to a long-term vascular catheter and shown to reduce the in vitro attachment of platelets and thrombus even after 60 days of blood product exposure. The technology has now been adapted to silicone hydrogel contact lenses to improve wettability. The hypothesis of this study is that by adding polybetaine to the surface of contact lenses, the advancing contact angle will be substantially decreased. Methods: Silicone hydrogel contact lenses were surface modified using a one-step controlled polymerization process. Contact lenses with biocompatible polybetainebased polymers were compared to unmodified (control) lenses. The surface characteristics were analyzed with surface staining, SEM-EDS, XPS, dynamic contact angle, and ATR-FTIR. The stability of the modification was evaluated Copyright 2012 by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. For permission to reproduce any abstract, contact the ARVO Office at [email protected]. ARVO 2012 Annual Meeting Abstracts under oxidative conditions, after autoclaving, and after rubbing. Results: Advancing contact angles were decreased by approximately 50 o. Unmodified silicone hydrogel lenses (n=25) had an advancing contact angle of 80 o +/- 3o and a receding angle of 29o +/- 2o. Semprus modified lenses (n=3) had an advancing contact angle of 27o +/- 2o and a receding angle of 26o +/- 2o. The surface modification had no effect on the bulk properties including clarity, dimensions, and mechanical properties. The modification was stable to oxidative solutions, sterilization and mechanical challenges. Conclusions: The polybetaine surface modification provides a novel and viable avenue for significantly improving the wettability of silicone hydrogel contact lenses without affecting their bulk properties. The advancing contact angle was substantially decreased while the receding contact angle was predictably maintained at a low level. The one-step process method is adaptable to various silicone hydrogel contact lenses with different formulations. Commercial Relationships: Alonzo Cook, Semprus BioSciences (E); Matthew Skinner, Semprus BioSciences (E); Jun Li, Semprus BioSciences (E); Christopher Loose, Semprus BioSciences (E); Karen Schultz, Semprus BioSciences (E); Zheng Zhang, Semprus BioSciences (E) Support: None Program Number: 6097 Poster Board Number: D918 Presentation Time: 8:30 AM - 10:15 AM Proteoglycan 4 (lubricin) Enhances the Wettability Of Model Conventional And Silicone Hydrogel Contact Lenses Lakshman N. Subbaraman1, Tannin A. Schmidt2, Heather Sheardown1. 1Chemical Engineering, McMaster University, Hamilton, ON, Canada; 2Biomedical Engineering, University of Calgary, Calgary, AB, Canada. Purpose: Proteoglycan 4 (PRG4), a mucin-like glycoprotein, is present in the synovial joints and synovial fluid. PRG4 improves lubrication and contributes to the overall maintenance and integrity of the knee joint. PRG4 has recently been discovered at the ocular surface and as such may be useful in ocular applications as a lubricant. The purpose of this study was to incorporate PRG4 into model conventional hydrogel (CH) and silicone hydrogel (SH) contact lens materials and to determine the effect of PRG4 on surface characteristics and protein-sorption properties of these contact lenses. Methods: One model CH (poly(2-hydroxyethyl methacrylate) [pHEMA]) and two model SH (pHEMA,Methacryloxypropyltris(trimethylsiloxy)silane [pHEMA TRIS] and N,N-Dimethylacrylamide, TRIS [DMAA TRIS]) lens materials were prepared with and without hyaluronic acid (HA) of molecular weight 35 or 132 kDa. PRG4 was isolated and purified from articular cartilage disks harvested from mature bovine stifle joints. PRG4 was incorporated into these materials at two different concentrations (1% and 5% by weight). Advancing water contact angle (CA), equilibrium water content, optical transparency (OT) and lysozyme sorption on these lens materials were investigated. Results: Presence of PRG4 significantly decreased the CAs of both the HA and non-HA containing materials (p<0.05). Materials with higher concentration of PRG4 (5% wt) showed lower CAs than those with lower concentration (1% wt) (p<0.05). Incorporation of PRG4 did not have an effect on the OT when compared to the control. While there was no significant difference between PRG4 containing and non-PRG4 containing pHEMA-based materials (p>0.05), PRG4 containing SH materials showed a significant reduction in lysozyme sorption when compared to non-PRG containing SH materials (p<0.05). All the HA containing materials showed significantly lower CAs and reduced lysozyme sorption than non-HA containing materials (p<0.05). Conclusions: Incorporation of PRG4 improves the hydrophilicity and reduces protein sorption without affecting the OT in model SH contact lenses. SH materials that contain PRG4 and HA have tremendous potential as hydrophilic, proteinresistant contact lens materials. Commercial Relationships: Lakshman N. Subbaraman, None; Tannin A. Schmidt, None; Heather Sheardown, None Support: NSERC 20/20 Ophthalmic Network Program Number: 6098 Poster Board Number: D919 Presentation Time: 8:30 AM - 10:15 AM Estimating in-vivo Contact Lens Wettability Through Tear Film Hydrodynamics Jalaiah P. Varikooty1A, Nancy J. Keir1A, Trefford L. Simpson1B. ACCLR, School of Optometry, BSchool of Optometry, 1University of Waterloo, Waterloo, ON, Canada. Purpose: The stability and ease of spread of the tear film over the lens surface may be an indicator of contact lens wettability. The present in-vivo methods of determining lens wettability are complex and do not predict the comfort of lens wear. We introduce a novel and objective way of determining in-vivo lens wettability. Methods: 20 videos from 10 participants who had worn the same type of silicone hydrogel lens for at least 8 hours were analysed. We imaged the spread of tear-film over the lens surface after a blink, in the morning after lens insertion and also after 8 hours of lens wear. Using a customized, calibrated ImageJ macro the velocity of reflective particles in the videos was determined. The results were analyzed using R and ProFit. Results: The upward particle velocity (UPV) was highest immediately after a blink and declined with time. We were able to establish that the spread of the tear film was different upon lens insertion than it was after 8 hours of lens wear by measuring UPV (p=0.001). The exponential time constants were 11.5±1.7 for lens insertion in the morning and 47.1 ± 28.0 after 8 hours of lens wear. Conclusions: We have introduced a novel and non-invasive way to measure invivo wettability of the lens/tear-film interface. Additional studies are needed to understand if this simple measure is associated with other aspects of lens wettability or lens comfort. Commercial Relationships: Jalaiah P. Varikooty, None; Nancy J. Keir, None; Trefford L. Simpson, None Support: None Program Number: 6099 Poster Board Number: D920 Presentation Time: 8:30 AM - 10:15 AM Hyaluronan Release from Contact Lenses in vitro and in vivo Krista M. Fridman, Catherine A. Scheuer, Stephanie Su, Lening Zhang, Susan E. Burke. Bausch + Lomb, Rochester, NY. Purpose: Hyaluronan (HA), a natural ocular lubricant, provides hydration and contributes to tear film stabilization. This study evaluates in vitro contact lens adsorption and release of HA after soaking in multi-purpose solution containing HA. Further, this study examined the concentration of HA in tear film of lens wearers after use of MPS containing HA. Methods: In vitro adsorption and release of HA from senofilcon A lenses (Acuvue Oasys, Vistakon) were evaluated with fluorescence spectroscopy. Lenses were soaked in MPS (Biotrue, Bausch+Lomb) prepared with fluorescent-tagged HA. Release profiles were monitored over time with saline rinse of soaked lenses at the rate of tear film secretions. In vivo release of HA from senofilcon A lenses soaked in MPS containing HA (Biotrue, Bausch+Lomb) was evaluated with ELISA. Twenty five subjects matched for age and sex (12 habitual lens wearers and 13 nonlens wearers) participated in this randomized, single-masked, contralateral study. Tears were collected on Schirmer strips at baseline and after 2h of wearing MPS soaked lenses or control lenses rinsed with Sensitive Eyes Saline. HA concentrations were measured and adjusted for sample volumes. A repeated measurement ANOVA model was used to evaluate differences in HA concentrations. Results: In vitro measurements showed adsorbed HA (19.72+/-2.03 µg HA/lens) was released over time from senofilcon A. In vivo HA tear concentrations obtained were in range with those previously reported (undetectable - 3018ng HA/ml tears). No statistical differences were noted in this study population between lens wearers and non-lens wearers, between baselines of treatment groups, or between saline treatment group and baseline. An increase in HA concentration was observed in tears collected from eyes that had worn lenses soaked in MPS containing HA compared to baseline (p=0.009), and compared to those with saline rinsed control contact lenses (p=0.033). Conclusions: This study showed that senofilcon A lenses adsorbed HA when soaked in MPS containing HA and that HA release was detected for 20h when rinsed in vitro at the rate of tear film secretions. This study also showed that after wearing senofilcon A lenses soaked in an HA containing MPS, the HA concentration in tear film may be increased. The duration of in vivo HA increase was not evaluated. Copyright 2012 by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. For permission to reproduce any abstract, contact the ARVO Office at [email protected]. ARVO 2012 Annual Meeting Abstracts Commercial Relationships: Krista M. Fridman, Bausch + Lomb (E); Catherine A. Scheuer, Bausch + Lomb (E); Stephanie Su, Bausch + Lomb (E); Lening Zhang, Bausch + Lomb (E); Susan E. Burke, Bausch + Lomb (E) Support: None Clinical Trial: http://www.clinicaltrials.gov, 1317030 Program Number: 6100 Poster Board Number: D921 Presentation Time: 8:30 AM - 10:15 AM Solute Release From Soft-contact-lens Hydrogels Csaba Kotsmar, Teresa Nadolski, Nicole Taylor, Kevin Yeh, Clayton J. Radke. Chemical & Biomolecular Eng, Univ of California at Berkeley, Berkeley, CA. Purpose: Transport of solute molecules through soft-contact-lens (SCL) hydrogels, such as salts, wetting agents, nutrients, and drugs, is important to on-eye behavior. Typically, solutes are loaded into the gel and released over time. This work measures the mesh size of contact-lens materials and demonstrates that solute absorption and release times decrease with increasing mesh size. For solutes that interact strongly with the gel matrix, release times are much slower than loading times and can approach infinity for irreversible interactions. Methods: Two-photon confocal microscopy detects the transient concentration profiles of fluorescently tagged dextrans and proteins with different charges in HEMA/MAA hydrogels during both loading and release (see Figure 1 for sodium fluorescein). Diffusion theory gives the solute effective diffusion coefficient D. Oscillatory shear rheometry gives the gel mesh size. Results: For uncharged dextrans of molecular weight near 10 kDa, D increases from 3.24±0.1 x 10-8 cm2/s to 4.02 ± 0.4 x 10-7 cm2/s both for absorption and desorption as the mesh size increases from 3 to 9 nm. These solutes interact reversibly with the gel. For protein oppositely charged to the gel network, the diffusion coefficient in the loading direction greatly decreases to 5.2±0.3 x 10-9 cm2/s. Desorption of the anionic protein is extremely slow indicating strong interaction with the gel strands. Conclusions: Using rheometry and polymer physics, we successfully measure mesh sizes of SCL materials. For reversibly interacting solutes, absorption and release rates increase with gel mesh size and are identical in both loading and release directions. For solutes that strongly interact with the gel, uptake rates are diminished and release rates are extremely slow. It is not possible to predict solute release rates from hydrogels using studies conducted in the loading direction only. Commercial Relationships: Csaba Kotsmar, Alcon (F); Teresa Nadolski, None; Nicole Taylor, None; Kevin Yeh, None; Clayton J. Radke, Alcon (F) Support: Alcon Program Number: 6101 Poster Board Number: D922 Presentation Time: 8:30 AM - 10:15 AM Ocular Delivery Of Ketotifen Fumarate By Silicone Hydrogel And Conventional Hydrogel Contact Lens Materials Anthony Soluri, Alex Hui, Lyndon Jones. Centre for Contact Lens Research, University of Waterloo, Waterloo, ON, Canada. Purpose: To investigate the uptake and delivery of the anti-allergy drug ketotifen fumarate (KF), by commercially available contact lenses. Methods: A total of fourteen different commercially available contact lenses were investigated, including five frequent replacement silicone hydrogels (balafilcon A, comfilcon A, galyfilcon A, senofilcon A and lotrafilcon B), three conventional hydrogels (alphafilcon A, etafilcon A, and polymacon) and six daily disposable lenses (nelfilcon A, omafilcon A, etafilcon A + PVP, ocufilcon B, narafilcon A and filcon II 3). Lenses were soaked in a 0.025% KF loading solution for 24 hours, and the concentration of KF in solution over time was determined by UV absorbance at 297 nm. After the 24 hour loading period, lenses were placed into fresh vials containing borate buffered saline (BBS), and the release of drug into solution at 34°C was monitored over 24 hours. Results: All the lenses studied demonstrated significant uptake and release of KF into the BBS (p<0.05 compared to initial time point). Lenses with charged surfaces (balafilcon A, etafilcon A and etafilcon A + PVP) demonstrated the greatest uptake and release of KF. Etafilcon A released 284.5 ± 29.8 µg/lens, while balafilcon A released 227.6 ± 14.7 µg/lens, which was substantially more (p<0.05) than the lowest releasing lenses (nelfilcon A; 40.4 ± 4.1 µg/lens and comfilcon A; 110.4 ± 8.9 µg/lens). The majority of lenses were able to match or exceed the total amount of KF commonly administered to the eye using twice daily dosing of commercially available (0.025%) eye drop formulations. Most of the lenses surveyed released to a plateau concentration of KF relatively quickly, and no lens was able to release KF for longer than four hours. Conclusions: Commercially available lenses demonstrated the ability to release a clinically relevant amount of KF compared to conventional eye drops. The use of commercially available contact lenses as a KF delivery system in a daily disposable wear scenario may be feasible. Commercial Relationships: Anthony Soluri, None; Alex Hui, None; Lyndon Jones, None Support: NSERC, COETF, 20/20 Network for the Development of Advanced Ophthalmic Materials, Ezell Fellowship, Vistakon Research Grant Program Number: 6102 Poster Board Number: D923 Presentation Time: 8:30 AM - 10:15 AM Development of a Drug released Soft Contact Lens that Releases Antibiotics in a Sustained Manner Shinichiro Kobayakawa1, Toru Matsunaga2, Kohji Kakisu1, Yoshiko Yamazaki2, Takao Sato2, Tetsuo Tochikubo1. 11st Dept of Ophthalmology, Toho University, Tokyo, Japan; 2SEED Co Ltd, Kounosu-shi, Japan. Purpose: We developed a new soft contact lens (SCL) of a hydrogel material capable of releasing antibiotics in a sustained manner. The purpose of this study was to investigate the penetration of the antibiotics to the eye by the drug released SCL (DR-SCL) in a rabbit model. Methods: Gatifloxacin (GFLX) 0.3% and moxifloxacin (MFLX) 0.5% eye drops were used. In twenty-seven rabbits, the antibiotics concentration of cornea, aqueous humor and crystalline lens was measured with high-performance liquid chromatography (HPLC). Those samples were collected at 10, 30, and 60 minutes after three times topical administration at 15-min intervals by those eye drops (eye drops group), and through the application with DR-SCL (DR-SCL group), also collected at 24, 48, and 72 hours through the application with DR-SCL. Results: The maximum GFLX concentration in cornea were 0.7μg/ml (@10 min), and the MFLX concentration were 2.4μg/ml (@10 min) in eye drops group. Whereas, those were 9.5μg/ml (@60 min) and 23μg/ml (@60 min) in DR-SCL group, respectively. Those concentrations were significant differences between eye drops group and DR-SCL groups at 10 min. The maximum GFLX concentrations in aqueous humor were 1.1μg/ml (@60 min), and the MFLX concentration were 6.4μg/ml (@60 min) in eye drops group. Whereas, those were 13.4μg/ml (@60 min) and 60μg/ml (@60 min) in DR-SCL group, respectively. Those concentrations were significant differences between eye drops group and DR-SCL groups at 60 min. The maximum GFLX concentrations in crystalline lens were 0.02μg/ml (@60 min), and the MFLX concentration were 0.17μg/ml (@30 min) in eye drops group. Whereas, those were 0.05μg/ml (@60 min) and 0.3μg/ml (@60 min) in DR-SCL group, respectively. Those concentrations in crystalline lens were not significant differences between eye drops group and DR-SCL groups. Those concentrations in cornea for GFLX in DR-SCL group decreased from 0.69μg/ml to 0.04μg/ml, and for MFLX decreased from 4.22μg/ml to 0.89μg/ml through 72 hours. Those concentrations in aqueous humor for GFLX decreased from 2.6μg/ml to 0.08μg/ml, and for MFLX decreased from 7.9μg/ml to 3.2μg/ml. Those concentrations in crystalline lens for GFLX decreased from 0.3μg/ml to 0.08μg/ml, and for MFLX decreased from 0.6μg/ml to 0.3μg/ml. Conclusions: Antibiotics concentrations of DR-SCL group either in aqueous humor or in cornea were approximately ten times higher than those of eye drops group. Those to crystalline lens in DR-SCL group were similar or higher than those in eye drops group. Moreover, DR-SCL sustained release of antibiotics through 72 hours. DR-SCL may be an expectable drug delivery system into the interior of the eye. Commercial Relationships: Shinichiro Kobayakawa, None; Toru Matsunaga, SEED Co Ltd (E); Kohji Kakisu, None; Yoshiko Yamazaki, SEED Co Ltd (E); Takao Sato, SEED Co Ltd (E); Tetsuo Tochikubo, None Support: None Program Number: 6103 Poster Board Number: D924 Presentation Time: 8:30 AM - 10:15 AM Copyright 2012 by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. For permission to reproduce any abstract, contact the ARVO Office at [email protected]. ARVO 2012 Annual Meeting Abstracts Surface versus Bulk Absorption of a Diblock Copolymer on/in Silicone Hydrogels Yuchen Huo1, Scott S. Perry1, Howard A. Ketelson2. 1Materials Science and Engineering, University of Florida, Gainesville, FL; 2R & D, Alcon Research Ltd, Fort Worth, TX. Purpose: The interaction between ethylene oxide-block-butylene oxide (EOBO) copolymer and the surfaces of four silicone hydrogel (SH) contact lenses PureVision® (PV), O2OPTIX® (O2), ACUVUE® Oasys® (AO), and Biofinity® (BF) was investigated using angle-resolved X-ray photoelectron spectroscopy (ARXPS) following treatment in test solutions containing various concentrations of EOBO. The nature of this interaction was further understood by quantifying the amount of eluted EOBO from each lens following the same treatment using ultra performance liquid chromatography (UPLC). Methods: Lenses were treated with solutions containing various concentrations of EOBO. For a given lens type and a specific concentration level, identical paired samples were prepared. The first sample was subjected to an elution study involving UPLC. The second sample, analyzed using XPS, was prepared through a vacuum drying procedure, in which the hydrogel is taken from a fully hydrated state directly to an ultraclean, ultrahigh vacuum environment. Upon changing the angle between the sample and the XPS analyzer, chemical compositions corresponding to uppermost 10 nm of the surface were probed for each sample. Results: The elution study revealed large disparity in the amount of EOBO uptake by different samples following each solution treatment. For samples subjected to the most concentrated solution treatment, the amount of EOBO recovered (in μg) from the lenses was ranked as the following, from the highest to the lowest, PV (151.77), BF (140.24), AO (77.96), and O2 (7.21). The XPS results, however, suggested that the amount of EOBO retained on the surface of the lenses demonstrated a largely different trend. For example, AO and BF displayed trivial amount of signal at binding energy characteristic to the EO blocks, whereas O2 and PV showed clear EO signature as a result of being present on the surface. Conclusions: The disparity between the elution and XPS results highlights the difference in the interaction mechanism of the EOBO copolymer with different lenses. For lenses such as O2OPTIX®, this interaction is predominantly bound to the surface; for ACUVUE® OASYS®, however, EOBO was preferentially absorbed by the bulk. Commercial Relationships: Yuchen Huo, Alcon Laboratories, Inc. (F); Scott S. Perry, Alcon Laboratories, Inc. (F); Howard A. Ketelson, Alcon Laboratories, Inc. (E) Support: Alcon Laboratories, Inc. Program Number: 6104 Poster Board Number: D925 Presentation Time: 8:30 AM - 10:15 AM Understanding Lens Shape Dynamics During Off-Eye Dehydration of Contact Lens Materials with Varying Water Content Ian G. Cox, Rosa H. Lee. Vision Care, Bausch + Lomb, Rochester, NY. Purpose: To understand the lens shape dynamics during off-eye dehydration for a novel lens material and 3 commercially available daily disposable contact lenses. Methods: Four -3.00D lenses of each lens (type, water content) (etafilcon A [AV Moist], 43%; narafilcon B, 48%; nelfilcon A, 69%; investigational lens, 78%) were tested. Each lens was taken out of the package and blotted to remove excess packaging solution. All 16 lenses were allowed to dehydrate under the same ambient conditions of approximately 72°F with a RH of 30%. A photo was taken every 2 minutes over the 20min period. Four pairs of photos for each lens type (time 0 and time 20mins) were presented to 12 random subjects who rated whether the lens shape of image A compared to image B was similar or different, using a 10 point rating scale where 1 corresponded to “Extremely Similar” and 10 corresponded to “Extremely Different”. Results: Shape changes occurred throughout the 20 minute period. All 3 commercially available contact lens materials showed significant edge “fluting” as a result of lens dehydration at the end of the 20 minute test period, while the investigational contact lens material did not. A one-way ANOVA showed a statistically significant difference (p<0.0001) between the investigational lens (A) compared to nelfilcon A (D), narafilcon B (C) and etafilcon A (B), where the mean rating scores were 1.9, 8.8, 8.4, 6.8, respectively. Conclusions: Traditional clinical literation and belief suggests that higher water content lenses dehydrate more than lower water content lenses. In this study, the novel lens material demonstrated a more consistent lens shape over the 20 minute dehydration period compared to narafilcon B, 48%; nelficon A, 69%; and etafilcon A, 43% lenses, suggesting that the investigational material has unique properties relative to water retention. Further research is needed to understand the impact of dehydration driven lens shape change on vision, comfort and fitting performance in-vivo. Commercial Relationships: Ian G. Cox, Bausch + Lomb (E); Rosa H. Lee, Bausch + Lomb (E) Support: None Program Number: 6105 Poster Board Number: D926 Presentation Time: 8:30 AM - 10:15 AM Oxygen Diffusion Behind Modern Scleral Rigid Gas Permeable Contact Lenses Sofia C. Peixoto-de-Matos1, Vicente Compañ2, Sergio Moya2, Jorge Jorge1, Jose M. Gonzalez-Meijome1. 1Center of Physics, University of Minho, Braga, Portugal; 2 Applied Thermodynamics, Universidad Politécnica de Valencia, Valencia, Spain. Purpose: Scleral lenses are used to compensate corneal irregularities creating a vaulting effect over the cornea. The goal of this study is to develop a model to define the theoretical oxygen tension behind modern scleral contact lenses made of different rigid gas permeable (RGP) materials and thickness and assuming different thickness of the tear layer behind the lens. Methods: Simulations of the partial pressure of oxygen across the cornea behind scleral contact lenses made of different materials (Dk=75 to 200 barrers) and different thickness (Tav=100 to 300 microns) were performed. A post-lens tear film thickness (Tpost-tear=100 to 350 microns) in the range of 150 to 350 microns was considered. Results: Combinations of thicker lenses with lower permeability fitted to create a pos-lens tear film thicker than 150 microns reduce the partial pressure of oxygen at the corneal front surface below 50 mmHg, similar to closed eye conditions without lenses. The lower the oxygen permeability of the lens material, the more significant the contribution of post-lens tear film layer to the depletion in oxygen availability to the cornea. A 100 microns increase in lens thickness will reduce between 17 and 21% the partial pressure of oxygen at the corneal surface for a 75 barrers material and about 6% for a 200 barrers material. The same increase in tear film thickness will have an impact of 14 to 16% in the partial pressure of oxygen at the corneal surface for a 75 barrers material and about 12 to 14% for a 200 barrers material. Conclusions: Tear film layer behind scleral RGP CL can significantly limit the diffusion of oxygen to the cornea. This effect is more significant for lower Dk values considered even when they fall in the range of 75 to 125 barrers. Scleral RGP CL must be manufactured with materials of at least 150 barrers of oxygen permeability in order to avoid a significant hypoxic effect under open eye conditions. Commercial Relationships: Sofia C. Peixoto-de-Matos, None; Vicente Compañ, None; Sergio Moya, None; Jorge Jorge, None; Jose M. GonzalezMeijome, PARAGON VISION SCIENCE (C) Support: None Program Number: 6106 Poster Board Number: D927 Presentation Time: 8:30 AM - 10:15 AM Rapid Measurement of Tear Oxygen Tension underneath Soft Contact Lenses by Frequency-Domain Phosphorimetry Sangly P. Srinivas1, Giovanna Guidoboni2, Lucia Carichino2, Yiran Jiang1, Joseph A. Bonanno1. 1Optometry, Indiana University, Bloomington, IN; 2Mathematics, IUPUI, Indianapolis, IN. Purpose: To measure the dynamics of tear oxygen tension (pO2) during soft contact lens wear using a non-invasive approach following a brief closure of the eyelids. Methods: A slit-lamp fluorometer was modified for rapid measurement of the oxygen-sensitive phosphorescence lifetime of Pd-meso-tetra (4-carboxyphenyl) porphyrin (λex = 530 nm; λem > 630 nm). The dye, bound to albumin, was coated on to the bottom surface of hydrogel lenses before use in healthy volunteers (Bonanno et al., IOVS, 43(2), 2002). The output of a green LED (Nichia Inc), which was modulated as a sine-wave at 1 KHz, was used as the excitation source. Phosphorescence, collected by the emission optics, held parfocal to that of excitation, was directed to the cathode of a photomultiplier tube (R928, Hamamatsu Inc). Oxygen-sensitive phase delay and demodulation were detected using a lock-in amplifier (SRS-830; 120 KHz bandwidth; Stanford Research Systems, Palo Alto, CA) and sampled at 50 Hz. The dynamics of pO2, calculated from phase delay Copyright 2012 by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. For permission to reproduce any abstract, contact the ARVO Office at [email protected]. ARVO 2012 Annual Meeting Abstracts using the Stern-Volmer equation, was compared to predictions from a 1-D transient O2 transport model governing diffusion and consumption across the lens + cornea matrix. The oxygen consumption across the cornea was assumed to follow Monod kinetics (Chhabra et al., J Biomed Mater Res B Appl Biomater., 90(1), 2009). Results: Rapid changes in the oxygen-sensitive phase delay and demodulations were observed following brief closure of the eyelids. The time to recover to a steady state increased with longer periods of eye closure (5 min). Thicker lenses (of low Dk/L) produced slower return to steady state (taking up to 35 secs) compared to that of the thin lens (< 5 secs). The corresponding dynamics of pO2 were similar to those predicted by the mathematical model using parameters reported earlier (Chhabra et al., 2009). Conclusions: In contrast to the time-domain phosphorimetry (Bonanno et al., IOVS, 2002), the frequency-domain approach for phosphorescence lifetimes offers much higher sampling frequencies (50 Hz compared to 1 Hz). This high sampling rate will enable more accurate estimation of the oxygen consumption rate and other parameters of interest in contact lens design. Commercial Relationships: Sangly P. Srinivas, None; Giovanna Guidoboni, None; Lucia Carichino, None; Yiran Jiang, None; Joseph A. Bonanno, None Support: NSF-DMS 0811138 (GG) and IU Collaborative research grant (GG). (Image Pro Analyser 7.0) was used to measure nerve length. One way independent ANOVA and post hoc paired t-tests (with Bonferroni correction) were used to compare groups. Results: There was a significant difference in central NFD between the groups (SCL: 24,870 ± 4,793 µm/mm2, OK: 18,466 ± 4,872 µm/mm2, NL: 24,931 ± 4,259 µm/mm2; ANOVA p<0.01). NFD was significantly less in OK than SCL (p<0.01) and NL groups (p<0.01). SCL was not different from NL (p>0.05). There was no difference in mid-peripheral NFD among all the groups (SCL: 23,544 ± 3,987 µm/mm2, OK: 22,677 ± 3,301 µm/mm2, NL: 22,435 ± 3,993 µm/mm2; ANOVA p>0.05). Conclusions: This study reveals an apparent decrease in central corneal nerve density in the SBNP in OK lens wear. This suggests that the mechanism underlying refractive change during OK treatment may also impact on the corneal nerve morphology in lens wearers. The implications of this finding in relation to corneal sensitivity require further study. Commercial Relationships: Edward Lum, None; Blanka Golebiowski, None; Helen A. Swarbrick, Bausch & Lomb Boston, BE Enterprises, Capricornia Contact Lens. (F) Support: Funded under the Australian Research Council Linkage Project Program Number: 6107 Poster Board Number: D928 Presentation Time: 8:30 AM - 10:15 AM Surface Characterization of a Water Gradient Silicone Hydrogel Contact Lens (delefilcon A) John Pruitt, Yongxing Qiu, Sibichen Thekveli, Rick Hart. Alcon, Johns Creek, GA. Purpose: A water gradient silicone hydrogel contact lens recently introduced in Europe provides substantially different properties at the lens surface compared to the lens core. Multiple analytical techniques were utilized to characterize the core, surface, and water gradient properties of DAILIES® TOTAL1® (delefilcon A) contact lenses. Methods: Lenses were cross-sectioned to measure the transition from the core of the lens to the surface. The hydrated cross sections were placed on edge and imaged using atomic force microscopy (AFM). The surface thickness and the local compression modulus were measured along a line from the core to the outer surface. Dried contact lens cross sections were also imaged by both SEM and AFM to compare the dry vs. wet surface thickness to measure the surface water content. Gravimetric water content analysis was conducted on separately prepared samples consisting of only the high water content surface hydrogel material or the core silicone hydrogel material. Results: A total surface thickness of 5.9 ± 0.8 microns was measured using AFM of hydrated lens cross sections including a transition zone of 1-2 microns and an outer surface layer of 4-5 microns. The surface layer was characterized by a lower compression modulus than the core of the lens with a modulus gradient detectable in the transition zone. Gravimetric analysis of a separately prepared sample of the surface hydrogel material revealed a water content of 84.6% compared to a core water content of 33 ± 2%. The surface thickness of a vacuum dried lens cross section was measured at 1.2 microns, only 20% of the hydrated surface thickness and consistent with an average water content in the surface layer of approximately 80%. SEM images of freeze-dried lens samples revealed a porous surface structure as expected due to the high water content. Conclusions: Delefilcon A contact lenses are composed of a core silicone hydrogel material consisting of approximately 33% water which transitions to an outer surface layer containing approximately 80% water. The surface is also characterized by a lower compression modulus compared to the core of the lens. This unique water gradient technology resulting in high oxygen transmission with a lubricious surface represents the next generation of contact lenses. Commercial Relationships: John Pruitt, Alcon (E); Yongxing Qiu, Alcon (E); Sibichen Thekveli, Alcon (E); Rick Hart, Alcon (E) Support: None Program Number: 6109 Poster Board Number: D930 Presentation Time: 8:30 AM - 10:15 AM Design and Development of an In Vitro Tear Replenishment System Saman Mohammadi, Maud Gorbet. Systems Design Engineering, University of Waterloo, Waterloo, ON, Canada. Purpose: When testing contact lens biocompatibility, an important missing element with in vitro models of the cornea is the constant hydration of the contact lens and exchange of tear fluid that occurs in the eye. The purpose of this project was to design a novel physiologically realistic microfluidic device to mimic tear replenishment in the human eye through spraying, at physiological rates, artificial tear fluid onto the surface of the contact lens on a curved in vitro cornea model. Methods: The microfluidics system provides a pressurized artificial tear fluid supply line controlled through a series of isolation valves and can deliver the desired amount of artificial tear fluid on the surface of the in vitro model. A micropump was used to pump the artificial tear fluid through Teflon (TM) tubing. Sixwell inserts were curved using a stainless steel die designed to mimic the curvature and dimension of the cornea. The curved inserts with or without human corneal epithelial cells (HCEC) were transferred into the device in a sterilized environment. The excess tear fluid was pumped out from each well into a waste container. The entire device was placed in a cell incubator and tested for up to 12 hours. Results: The experiments on contact lenses in the absence of cells showed the device can keep the contact lens hydrated over any period of time while maintaining lens exposure to air in between tear fluid delivery, mimicking in vitro tear break-up over a contact lens. The device allowed enough air exchange within a 5% CO2 regulated incubator to maintain medium pH levels within physiological range. MTT viability studies on a curved stratified culture of immortalized corneal epithelial cells showed no significant change in cell viability with lotrafilcon A lenses. Experiments using the tear replenishment system on the in vitro model without a contact lens, showed slightly lower cell viability in the superficial layer but no significant change in overall cell viability compared to controls where no tear replenishment was applied. Conclusions: Our results proved this physiologically realistic modeling of tear replenishment system can provide artificial tear fluid to a lens on a curved surface with or without a multilayer of HCEC, at flow rates and frequency similar to the human eye. This device allows mimicking in vivo conditions more closely and will contribute to a better understanding of corneal cell-lens interactions in vitro. Commercial Relationships: Saman Mohammadi, None; Maud Gorbet, None Support: NSERC, CIBA Vision Program Number: 6108 Poster Board Number: D929 Presentation Time: 8:30 AM - 10:15 AM Corneal Nerve Morphology In Soft And Orthokeratology Contact Lens Wear Edward Lum, Blanka Golebiowski, Helen A. Swarbrick. Sch of Optometry/Vision Sci, Univ of New South Wales, Sydney, Australia. Purpose: To investigate the morphology of the corneal sub-basal nerve plexus (SBNP) in soft and orthokeratology contact lens wearers using laser-scanning confocal microscopy (LSCM). Methods: Forty-three subjects (age range: 18 to 76 yrs) were recruited in a crosssectional study and grouped into three categories: daily wear soft (SCL, n=17, median lens wear experience 10yrs), overnight orthokeratology (OK, n=8, median lens wear experience 2yrs), and non-lens wearers (NL, n=18). Nerve morphology was assessed by sampling a 1x1mm area of the SBNP using the Heidelberg Retina Tomograph with Rostock Corneal Module at two locations: corneal apex and temporal mid-periphery approximately 2.5mm from apex. Nerve fibre density (NFD) was calculated by measuring the total length of all nerve fibres and branches per square millimetre. A stylus and tracing tool in an image-processing program Program Number: 6110 Poster Board Number: D931 Presentation Time: 8:30 AM - 10:15 AM Evaluation of Contact Lens Image Stability and Predicted logMAR Image Resolution as Lenses Dehydrate Rosa H. Lee, Amanda C. Kingston, Gary Richardson. Product Design Group, Bausch + Lomb, Rochester, NY. Purpose: To use a novel optical bench technique to analyze the image stability and predicted logMAR retinal image resolution of 1 investigational and 3 commercially available daily disposable contact lenses as the lenses dehydrate. Methods: Twenty -3.00D lenses of each product type (etafilcon A [AV Moist], narafilcon B, nelfilcon A, test lens) were analyzed on an optical imaging bench. The bench uses a model cornea that mimics the optics and physical dimensions of an average human eye, and relays the retinal plane image of a target (US Air Force) to a CCD camera. Multiple images were captured through each lens over time with a target at optical infinity. Each lens was blotted to remove excess packaging solution and conformed to a 7.8mm radius PMMA model cornea. Two drops of rewetting solution were used to simulate the tear film. Images were acquired every 10s, as the lens is dehydrating, up to 180s following application of the rewetting Copyright 2012 by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. For permission to reproduce any abstract, contact the ARVO Office at [email protected]. ARVO 2012 Annual Meeting Abstracts drops. A pattern-matching algorithm was used to calculate the predicted logMAR score of the images from each lens following normalization against the initial time zero image for each image series. Results: A one-way ANOVA showed a statistically significant difference (p<0.001) between the test lens compared to nelfilcon A, narafilcon B and etafilcon A, where the overall predicted mean logMAR scores were -0.009, 0.116, 0.136 and 0.182. For the time 0 images, there was a statistically significant difference between the test lens and nelfilcon A (p<0.03) with mean predicted logMAR scores of -0.11 and -0.05, respectively. For the time 10s images (shorter than blink rates associated with reading or computer use), there was a statistically significant difference between the test lens compared to nelfilcon A and etafilcon A (p<0.001) with mean predicted logMAR scores of -0.10, -0.02, -0.03, respectively. Conclusions: This novel in-vitro method quantitates the predicted logMAR score based on optical image quality as lenses dehydrate. The test lenses exhibited better optical image quality than the 3 commercially available daily disposable lenses. The test lens showed a more consistent and slower reduction in predicted retinal image quality over time compared to narafilcon B and etafilcon A lenses. Within 10s, there was a predicted 4 letter difference between the test lens and nelfilcon A and a 3.5 letter difference for etafilcon A. Further research is needed to understand the clinical impact to visual stability. Commercial Relationships: Rosa H. Lee, Bausch + Lomb (E); Amanda C. Kingston, Bausch + Lomb (E); Gary Richardson, Bausch + Lomb (E) Support: None Program Number: 6111 Poster Board Number: D932 Presentation Time: 8:30 AM - 10:15 AM Interfacial Interactions Of Cationic And Anionic Artificial Tears With Ionic Hydrogel Contact Lens Surface Muhammad Abdulrazik1, Simon Benita2. 1Ophthalmology/Innovative Interventions, East Jerusalem Biomedical Institute, East Jerusalem, Palestine; 2Institute of Drug Research, Hebrew University of Jerusalem, Jerusalem, Israel. Purpose: Contact lens wear is a predisposing factor to dry eye. However, no artificial tear product is approved for use while wearing contact lenses due to biocompatibility concerns. Ionic and non-ionic hydrogel and silicon hydrogel soft contact lenses are the most common in current clinical use. This study aims at investigating interfacial interactions between cationic and anionic artificial tear preparation and the surface of ionic hydrogel contact lenses. Methods: The two studied ionic contact lenses were FDA category III and IV hydrogel lenses (Hanita, pHEMA/MAA, 38% and 57% water content respectively). The studied formulations with electrostatic charge were Refresh EnduraTM anionic emulsion (Allergan) and Cationorm® cationic emulsion (Novagali Pharma). The studied reference formulations were HyloComod® (Ursapharm), HypoTears® (Novartis), GenTeal® (Novartis), Refresh® (Allergan) and Saline 0.9%. Contact lens was mounted on freshly excised rabbit eye globe. Contact angles were measured by FTA 125 system (First Ten Angstroms Inc.), formulation surface tension was determined by multiwell plate tensiometer (Kibron Inc.) and spreading coefficients were calculated from measured surface tensions and contact angles. Kruskal-Wallis test was used for determination of significance (P less than 0.05). Results: For each studied formulation, contact angles were significantly lower on 57% water content (WC) compared with 38% WC lens. Contact angle scores on both contact lenses were lowest for the cationic emulsion (27.16±3.54 on 38% WC surface and 8.98±2.32 on 57% WC surface), which significantly outperformed the anionic emulsion (49.47±4.73 on 38% WC surface and 17.68±1.94 on 57% WC surface). However, contact angle scores for the anionic emulsion were significantly lower than the non-charged formulations on each contact lens (from 63.41±4.4 [REFRESH] to 80.76±2.43 [HYPOTEARS] on 38% WC surface, and from 45.25±0.68 [REFRESH] to 62.02±4.39 [HYPOTEARS] on 57% WC surface). Conclusions: The effect of contact lens water content on contact angles was steeper than the effect of formulation electrostatic charge. However, comparison between formulation on each of the studied surfaces have shown the superiority of the cationic emulsion that achieved approaching-zero spreading coefficients (-3.32 ± -0.85 and -0.38 ± -0.19 mN/m, for 38% and 57% WC surface respectively) (spreading coefficient = 0 represents a spontaneous and complete wetting), suggesting that electrostatic attraction have a strong impact on interfacial interaction between instilled eye drop and contact lens surface. The results support the utilization of cationic-charge approach in the design of tear substitutes for contact lens wearers. Commercial Relationships: Muhammad Abdulrazik, None; Simon Benita, inventor (P) Support: None Program Number: 6112 Poster Board Number: D933 Presentation Time: 8:30 AM - 10:15 AM Contact Lens/Contact Lens solution Combinations Determine the Inflammatory Changes on the Ocular Surface: A Laser In Vivo Confocal Microscopy Study Bernardo M. Cavalcanti1, Andrea Cruzat2, Yureeda Qazi3A, Neda Baniasadi4, Monique Trinidad3B, Amy Watts3C, Douglas Critser5A, Charles Leahy3C, Christine W. Sindt5B, Pedram Hamrah1. 1Cornea/Ophthalmology, Harvard Medical School/MEEI, Boston, MA; 2Cornea / Ophthalmology, Harvard Medical Sch/MEEI, Boston, MA; AOphthalmology, BCornea Research, CContact Lens, 3 Massachusetts Eye and Ear Infirmary, Boston, MA; 4Cornea/Ophthalmology, MA Eye & Ear Infirm/Harvard Med Sch, Boston, MA; AContact Lens, B Ophthalmology, 5University of Iowa, Iowa City, IA. Purpose: To assess the subclinical immune responses to various contact lenses (CL) and CL solutions in naive CL wearers. Methods: Multicenter, randomized, double-blinded, clinical trial. Sixty-five naïve CL wearers (130 eyes), fitted with silicone hydrogel CL (PureVision® [PV]; Oasys® [OA]; Biofinity® [BF]), were enrolled into one of 3 CL solution groups (OPTI-FREE RepleniSH® (OF, n=21); Clear Care® (CC, n=21); ReNu MultiPlus® (RM, n=23). Corneal, limbal, and conjunctival staining, ocular injection, as well as laser in vivo confocal microscopy (IVCM; HRT3/RCM) of the central and peripheral corneal quadrants were performed at baseline and weeks 1 and 6 post-CL wear. Three masked observers analyzed the images for dendritic cell (DC) and non-dendritic inflammatory cell (IC) density. Results: Increased ocular surface staining, but minimal ocular injection was observed in all groups. Conjunctival staining correlated to peripheral DC density (r>0.40 for all quadrants). RM demonstrated significantly increased staining for all conjunctival, limbal and cornea areas, correlating with highest increase in DC density in central cornea (58%), nasal (26%) and temporal (24%) quadrants at 6 weeks, as compared to OF and CC (p<0.05 between groups). Comparison of CL types showed significantly increased limbal and corneal staining for OA (p<0.05) and corneal staining with PV (p<0.04), but minimal staining with BF, with OA demonstrating highest increase in total DC (27%) as compared to PV (13%) and BF (12%) (p<0.05 between groups). Surprisingly, each CL and CL solution demonstrated combinations with minimal surface staining and no significant increase in DC as well as combinations with significant increase staining, with increase in peripheral DC. Conclusions: IVCM revealed increased immune cell infiltration in all groups after CL wear as early as 1 week, while corneal and conjunctival staining were detected later at 6 weeks. While our data demonstrates that increased ocular surface staining and immune cell density are both due to CL and CL solutions, proper combination will both prevent or worsen staining and subclinical increase in immune cells. Commercial Relationships: Bernardo M. Cavalcanti, None; Andrea Cruzat, None; Yureeda Qazi, None; Neda Baniasadi, None; Monique Trinidad, None; Amy Watts, Alcon (F); Douglas Critser, None; Charles Leahy, Alcon (F); Christine W. Sindt, Alcon (F); Pedram Hamrah, Alcon (F) Support: Support: NIH K08-EY020575, New England Corneal Transplant Research Fund, Falk Medical Research Trust, Alcon Research LTD. Clinical Trial: http://www.clinicaltrials.gov, NCT01250925 Program Number: 6113 Poster Board Number: D934 Presentation Time: 8:30 AM - 10:15 AM Stress Induced Frictional Transitions in Cross-Linked Surface Gels Thomas E. Angelini1, Alison C. Dunn1, Juan M. Uruena1, Howard A. Ketelson2, W G. Sawyer1A. AMechanical and Aerospace Eng, 1University of Florida, Gainesville, FL; 2R & D, Alcon Research Ltd, Fort Worth, TX. Purpose: To determine the contact pressure limits on lubricity for a lightly crosslinked gel surface layer as a function of cross-link density. This study examines the friction response of the gel layer under varied loads and sliding speeds and correlates the changes in lubricity to contact pressure and the mechanics of the gel surface. Methods: A series of experimental and minimally-crosslinked 2-3 um thick gradient gel layers (5) were created on silicone hydrogel contact lens surfaces (DAILIES TOTAL1®). Friction measurements were carried out on a custom micro-tribometer under low sliding speeds of v=20 um/s and very low pressures down to single kPa. Instrumented indentation experiments were performed using a micro-indentation platform, and the elastic constants of the gels were determined from these experiments. Results: The majority of samples showed a clear transition between dynamic stickslip friction (mu~0.25 with fluctuations of ~0.25) to extremely smooth and low friction (mu~0.03 with no measurable fluctuations) at forces ranging 230-490 mN. Based on the contact mechanics experiments performed on these lenses this corresponds to contact pressures between 9-13 kPa. There was a clear and monotonic trend indicating that gel stiffness and the transition pressure increase with increasing crosslinked density. All gels transitioned at surface deformations on the order of their thicknesses, thus it is hypothesized that the mechanisms of these frictional transitions is due a collapse of the fluid retaining network. Conclusions: The crosslinked density and resulting elasticity define the critical transition pressure between stick-slip and smooth friction. This transition deformation is comparable to gel thickness. At pressures greater than the threshold, the surface gel layer collapses locally, causing undesirable stick-slip friction. The conditions under which a soft surface gel layer on a bulk soft contact lens provides smooth sliding have been identified. Copyright 2012 by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. For permission to reproduce any abstract, contact the ARVO Office at [email protected]. ARVO 2012 Annual Meeting Abstracts Commercial Relationships: Thomas E. Angelini, None; Alison C. Dunn, None; Juan M. Uruena, None; Howard A. Ketelson, Alcon (E); W. G. Sawyer, None Support: Alcon Research, Ltd. Program Number: 6114 Poster Board Number: D935 Presentation Time: 8:30 AM - 10:15 AM Surface Mechanical and Tribological Properties of Silicone Hydrogels Measured by Atomic Force Microscopy Alexander Rudy1, Yuchen Huo1, Scott S. Perry1, Howard A. Ketelson2. 1Materials Science and Engineering, University of Florida, Gainesville, FL; 2R & D, Alcon Research Ltd, Fort Worth, TX. Purpose: The surfaces of four types of silicone hydrogel (SH) contact lenses(PureVision®, ACUVUE® Oasys®, ACUVUE® TruEye®, DAILIES® TOTAL1®) and the pHEMA-based ACUVUE® 2 were analyzed using atomic force microscopy (AFM) in aqueous environment. The elastic modulus, frictional, and adhesive properties of each lens were evaluated using calibrated instrumentations, providing a basis for comparing the distinctive surface properties of these lenses at the top 1 μm of the surface. Methods: All samples were prepared by soaking in buffered saline (Unisol® 4) for 24 hours to exchange out the blister pack solutions. Cantilevers modified with 5μm (diameter) silica colloidal probes were employed in the following experiments. Elastic modulus was measured by indenting the probe into the surface of the hydrogel in a controlled manner (i.e. approach speed and maximum applied force), such that the maximum indentation depth was restricted to sub-micron levels. A modulus value was obtained by fitting the characteristic force versus indentation behavior to a mathematical model. The frictional force was measured for the sliding contact of the probe and the surface at the length scale of 500 nm and with applied loads up 20 nN. The friction coefficient was realized by evaluating the linear dependence of friction force on applied normal load. Results: The lenses examined exhibited an order of magnitude difference_from the softest to the stiffest sample_in modulus value, generally reflective of the distinct surface treatments they received during manufacturing. For example, the pHEMAbased ACUVUE® 2 was shown to have a modulus between 100 and 130 kPa, whereas PureVision®‟s was an order of magnitude higher in value. The frictional properties followed a similar trend with plasma surface treated lenses, such as PureVision®, exhibiting coefficients of friction five times those of a non plasma treated lens, such as DAILIES® TOTAL1®. Conclusions: The elastic modulus and frictional properties of different lenses have been evaluated on a nanoscopic level by AFM, depicting a strong correlation between the surface treatments and the apparent mechanical behaviors of the lenses. Commercial Relationships: Alexander Rudy, Alcon Laboratories, Inc. (F); Yuchen Huo, Alcon Laboratories, Inc. (F); Scott S. Perry, Alcon Laboratories, Inc. (F); Howard A. Ketelson, Alcon Laboratories, Inc. (E) Support: Alcon Laboratories, Inc. Program Number: 6115 Poster Board Number: D936 Presentation Time: 8:30 AM - 10:15 AM Surface Segregation of Chemical Moieties in Silicone Hydrogels Scott S. Perry1, Clay Argenbright1, Yuchen Huo1, Howard A. Ketelson2. 1Materials Science and Engineering, University of Florida, Gainesville, FL; 2R & D, Alcon Research Ltd, Fort Worth, TX. Purpose: This objective of this study was to determine the extent to which compositional variation occurs within the near-surface region of silicone hydrogels as a function of chemical environment. As few analytical techniques are available for in-vivo lens characterization, it is necessary to understand the influence of measurement environment on surface properties, as similar effects may impact the in-eye performance of these hydrogel lenses. Methods: X-ray photoelectron spectroscopy (XPS), a vacuum-based surface analytical technique was used to measure the chemical composition of the nearsurface region (~10 nm) of three silicone hydrogel (SH) contact lenses ( DAILIES® TOTAL1®, ACUVUE® TruEye®, and PureVision®). Lenses were introduced into a vacuum load lock in a fully hydrated state and then cryogenically cooled to 100K under a 1 atm nitrogen environment. The frozen lens was then transferred to an UHV environment while maintaining the lens temperature below 140K so as to avoid the complete desorption of the covering ice layer. The lens was then annealed to specific temperatures to sequentially remove water from the interface. The core level spectra of the lens elemental constituents were recorded as a function of temperature and used to calculate relative compositions as a function of lens dehydration. Results: The temperature-dependent surface compositions, correlated with lens dehydration, depict the mobility of chemical moieties within the hydrogel structure and the migration of species to the interface as dehydration occurs. For example, a 5 atomic % increase in N was observed upon dehydration of the DALIES® TOTAL1® lens. For the entire series, it is noted that only single digit changes are observed over the entire range of temperatures. Variations in the extent of compositional changes are consistent with known surface treatments of the different lens types. Conclusions: XPS represents a powerful probe of silicone hydrogel surface composition. While performed in a vacuum environment, temperature-programmed dehydration of the lens surface demonstrates that only minor changes in composition are observed in moving from a fully hydrated to fully dehydrated state. Commercial Relationships: Scott S. Perry, Alcon Laboratories (F); Clay Argenbright, Alcon Laboratories (F); Yuchen Huo, Alcon Laboratories (F); Howard A. Ketelson, Alcon Laboratories (E) Support: Alcon Laboratories Program Number: 6116 Poster Board Number: D937 Presentation Time: 8:30 AM - 10:15 AM Surface Characterization of Dailies Contact Lens Material James W. Davis, Howard A. Ketelson. R & D, Alcon Research Ltd, Fort Worth, TX. Purpose: This study describes the wetting and lipophilic properties of two silicone hydrogel daily disposable contact lenses, DAILIES TOTAL1® (DT1) and ACUVUE® TruEye® (ATE), under various experimental conditions from out of pack, 24 hour saline soak and air/saline rinses. Methods: Two contact angle methods were used to measure the advancing contact angles (ACA) of the lenses. The sessile drop (SD) was used to measure the static angle, while Captive Bubble (CB) was used to measure the static and dynamics of re-wetting. The bulk and lens surface properties were characterized using a lipophilic dye, Sudan IV, soak with the lenses. This was then extracted and UVVIS absorbance was measured at the maxima. Results: SD demonstrated low ACA for both DT1 and ATE, from OOP, 3.3° ± 2° and 2.3° ± 2° respectively. SD demonstrated low ACA for both DT1 and ATE, from a 24hour saline soak, 3.8° ± 2° and 4.8° ± 2° respectively. SD demonstrated significant differences in ACA for both DT1 and ATE, from 10 cycle rinse with saline/90sec air, 32.2° ± 4° and 89.6° ± 5° respectively (p<0.05). For CB, both lenses demonstrated low ACA for OOP and 24 hour saline soak. CB demonstrated differences in ACA at 160sec for both DT1 and ATE from 10 cycle rinse with saline/90sec air, 21.9° ± 3° and 30.3° ± 5° respectively (p<0.05). The lipophilic dye amount from 16 hour exposure demonstrated a lower amount for DT1, 920ppm ± 60ppm, vs ATE, 2900ppm ± 130ppm (p<0.05). Conclusions: We demonstrate that the new DAILIES® TOTAL1® provides superior wetting and hydrophilic properties under various experimental and environmental conditions. The new DAILIES® TOTAL1® material has superior hydrophilic surface and bulk properties that can impact in-eye daily lens performance. Commercial Relationships: James W. Davis, Alcon Laboratories, Inc. (E); Howard A. Ketelson, Alcon Laboratories, Inc. (F) Support: None Program Number: 6117 Poster Board Number: D938 Presentation Time: 8:30 AM - 10:15 AM Evaluation of In Vitro Cytotoxicity Assays for Contact Lens Multi-Purpose Solutions Mercedes Salvador-Silva1A, Ling C. Huang1A, Charles H. Powell1B, Lisa Hoong1B, Rosanne M. Yetemian1A. AR&D - Biological Sciences, BCorneal R&D, 1Abbott Medical Optics (AMO), Santa Ana, CA. Purpose: Previous methods assessing in vitro cytotoxicity of Contact Lens MultiPurpose Solutions (MPS) show a lack of correlation in relative responses. This study evaluates correlations among MPS effects on cell cytotoxicity, metabolic activity, membrane integrity, and biocompatibility. Methods: Six MPS were used: - MPS-1: polyquaternium (PQ-1) + alexidine (ALX), MPS-2: PQ-1 + 5 ppm myristamidopropyl dimethylamine (MAPD) + nonanoyl-EDTA, MPS-3: PQ-1 + 5 ppm MAPD, MPS-4: PQ-1 + 6 ppm MAPD, MPS-5: PQ-1 + polyhexamethylene biguanide (PHMB), and MPS-6: PHMB + poloxamer 237 (PLX). Five soft contact lens types (CLs) were used in this study: balafilcon A, senofilcon A, galyfilcon A, lotrafilcon B, and comfilcon A. In vitro biocompatibility was assessed according to ISO 10993. MPS-treated CLs (100mL, 4 days, n=3) were placed onto confluent HCEC SV40 cells for 24hrs. Cells were scored for reactivity according to USP Direct Contact Test criteria and quantitative analysis. MPS were evaluated at 100%, 50%, and 25% as diluted in cultured medium. Cytotoxicity and metabolic activity were determined using alamarBlue® dye. Corneal epithelial barrier function was assessed by ZO-1 IHC and lens preservative uptake-release by HPLC. Results: Results indicate that effects of MPS on HCEC are dependent on concentration, time of exposure, and the specific assay used. Lens preservative uptake-release data support the observed correlation between relative in vitro cytotoxicity of MPS and previously published clinical results. MPS-1, MPS-5, and MPS-6 demonstrated better ocular biocompatibility than MPS-2, 3 and 4 as measured by direct contact cytotoxicity score (0-2 vs. 2-4, respectively) and percent cell viability (>80% vs.< 45%, respectively, n=3). MPS did not alter integrity of corneal epithelial tight junctions under simulating in-use conditions when diluted at Copyright 2012 by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. For permission to reproduce any abstract, contact the ARVO Office at [email protected]. ARVO 2012 Annual Meeting Abstracts 50% with 5 minutes exposure. Conclusions: MPS effects on in vitro cell cytotoxicity are best demonstrated by correlation through multiple assays: cell metabolic activity, membrane integrity, and biocompatibility. These in vitro results showed that MPS-1 (PQ-1 + ALX) is highly compatible with all soft hydrogel lenses examined and provided evidence of similar performance to MPS-5 (PQ-1 + PHMB) or MPS-6 (PHMB + PLX), and better than MPS 2-4 (PQ-1 + MAPD combinations). Commercial Relationships: Mercedes Salvador-Silva, Abbott Medical Optics (E); Ling C. Huang, Abbott Medical Optics (E); Charles H. Powell, Abbott Medical Optics (E); Lisa Hoong, Abbott Medical Optics (E); Rosanne M. Yetemian, Abbott Medical Optics (E) Support: None Program Number: 6118 Poster Board Number: D939 Presentation Time: 8:30 AM - 10:15 AM Cytotoxic and Inflammatory Effects of Contact Lens Multipurpose Solutions on Human Corneal Epithelial Cells Nir Erdinest1A, Yoni Grosman1A, Rina Harari1A, Haim Ovadia1B, Abraham Solomon1B. AOphthalmology, BNeurology, 1Hadassah Hebrew University Medical Center, Jerusalem, Israel. Purpose: Clinical data show that contact lens (CL) multipurpose solutions (MPS) may cause damage to the ocular surface. This study examined the cytotoxic and inflammatory effects of eight commercially available CL MPS and hydrogen peroxide lens disinfection system on cultured human corneal epithelial (HCE) cells. Methods: HCE cells were exposed to eight different commercially available MPS products (MPS A, ReNu MultiPlus®; MPS B, Opti Free® EverMoist; MPS C, Solo-care Aqua®; MPS-D, Complete®; MPS-E, Unica Sensitive®; MPS-F, Options Multi®; MPS-G, Biotrue®; MPS-H, COMPLETE® RevitaLens) at concentrations of 30% v/v to 50% v/v for 4 to 18 hours. Cytotoxic effects were examined with FITC-Annexin V/ PI and MTT assay. The protein contents of the pro-inflammatory cytokines interleukin (IL)-6, IL-8, IL-1β and tumor necrosis factor-α (TNF-α) were examined by multiplex fluorescent bead immunoassay, and the mRNA expression of these cytokines was examined by Real time PCR. Lipopolysaccharide (LPS) complex (LPS combined with CD14 and LPS binding protein) and non-neutralized hydrogen peroxide lens disinfection system served as positive controls, and phosphate-buffered saline (PBS) was added as a negative control. Results: Incubation of the various MPS with HCE cells showed that all of the CL MPS examined induced higher levels of pro-inflammatory cytokines compared to the negative control. Multiplex fluorescent bead immunoassay results demonstrated that all five MPS, A, B, E, F and H stimulated the highest levels of proinflammatory cytokines in HCE cells. MPS H induced the highest concentrations of pro-inflammatory cytokines production (up to 5-fold higher levels of IL-6, up to 2.5-fold higher levels of IL-8, up to 39-fold higher levels of IL-1β and up to 14-fold higher levels of TNF-α) compared to the negative control (p<0.05). MPS E, B, A and F elicited up to 28-fold, 25.7-fold, 25.3-fold and 22.5-fold higher levels of IL1β, respectively. Similar responses were recorded in the expression profiles of the remaining cytokines. In contrast, no significant differences were noted in the cytotoxic and inflammatory effects between the hydrogen peroxide lens disinfection system and the negative control. Conclusions: MPS induced significant cytotoxic and inflammatory effects on cultured HCE cells compared to the negative control. In contrast, hydrogen peroxide lens disinfection system was the least cytotoxic and did not induce any inflammatory effect on human corneal epithelial cells. Taken together, these data suggests that hydrogen peroxide lens disinfection system is preferable as disinfecting and sterilizing system for CL compared to most of the commercially available MPS. Commercial Relationships: Nir Erdinest, None; Yoni Grosman, None; Rina Harari, None; Haim Ovadia, None; Abraham Solomon, None Support: This study was supported by grant no. 7803 from the Chief Scientist Office of the Ministry of Health, Israel. Nir Erdinest is grateful to the Azrieli Foundation for the award of an Azrieli Fellowship. Program Number: 6119 Poster Board Number: D940 Presentation Time: 8:30 AM - 10:15 AM The Impact of Intermittent Air Exposure on the Deposition of Lipids on Silicone Hydrogel and Conventional Hydrogel Contact Lens Materials Holly I. Lorentz, Miriam Heynen, Warda Khan, Diana Trieu, Lyndon Jones. Centre for Contact Lens Research, University of Waterloo, Waterloo, ON, Canada. Purpose: To evaluate the influence of air exposure during in vitro deposition of two model lipids on silicone hydrogel (SH) and conventional hydrogel (CH) contact lens materials, via a custom-designed model blink cell (MBC). Methods: Four SH (balafilcon A “BAL”; lotrafilcon B “LOB”; comfilcon A “COM”; senofilcon A “SEN”) and two CH (etafilcon A “ETA” and omafilcon A “OMA”) contact lens materials were mounted on six pistons and placed in a controlled atmosphere chamber at 35°C with a relative humidity of 18%. The pistons were connected to a motor that cycled the contact lenses in and out of an artificial tear solution (ATS). Lenses were cycled for 10 hours; 2 seconds in the ATS then exposed to air for 5 seconds, which allowed the tear film to break over the surface of the contact lens. Control lenses were kept submerged for 10 hours. The ATS used contained lipids, proteins, mucin, salts and a trace amount of one of the radioactive lipids; 14C-cholesterol (C) or 14C-phosphatidylcholine (PC). Following incubation, each lens was extracted twice, evaporated under nitrogen, resuspended in chloroform and then scintillation cocktail. Extracts were counted in a beta counter and raw data were translated into absolute amounts (ng/lens) via extrapolation from standard curves. Results: For the two model lipids tested, SH lens materials deposited statistically more lipid than the CH lens materials, with BAL depositing the most lipid. Air exposure significantly increased the amount of C that deposited on BAL, OMA, COM, and SEN (p≤0.03). No change in deposition was seen for LOB and ETA (p>0.05). All lenses exposed to air resulted in increased amounts of PC deposited. These levels were statistically significantly higher (p<0.04) for LOB, SEN, COM and OMA, but not statistically significant (p>0.05) for BAL or ETA. Conclusions: This model has demonstrated that lipid deposition kinetics can be impacted by air exposure and that lipid deposition profiles are contact lens dependent. In vitro models must begin to use more physiologically relevant incubation solutions and conditions that mimic contact lens wear within the natural tear film if in vitro data is to be extrapolated to the in vivo situation. Commercial Relationships: Holly I. Lorentz, Alcon (F); Miriam Heynen, Alcon (F); Warda Khan, None; Diana Trieu, None; Lyndon Jones, Alcon (F) Support: NSERC Canada. Program Number: 6120 Poster Board Number: D941 Presentation Time: 8:30 AM - 10:15 AM Clinical Performance and “ex-vivo” Dehydration of Silicone Hydrogel Contact Lenses with Two New Multipurpose Solutions Jose Manuel Gonzalez-Meijome, Ana Carla da Silva, Daniela Lopes-Ferreira, Helena Neves, Antonio Queiros Pereira. Center of Physics-Optometry, University of Minho, Braga, Portugal. Purpose: To evaluate the potential benefits of two novel multipurpose solutions (MPS) Complete RevitaLens® and Biotrue in preventing silicone hydrogel contact lens dehydration and the potential impact of lower dehydration in higher subjective comfort rates and better optical quality. Methods: This was a prospective, double-blind, bilateral and randomized study. Twenty-five neophytes wore Air Optix Aqua (Ciba Vision, Duluth, GA) for 1 month. They used one MPS solutions in one eye and the other MPS in the fellow eye in a random and double-masked way. After dispensing patients were evaluated after 2 and 10 hours of lens wear in the first day and after 2 and 10 hours of lens wear after 30 days. Tear film analysis with Tearscope Plus (Keeler, UK) and whole eye aberrations. Results: Lenses dehydrated to a similar extent regardless of the solution being used. There were no significant changes in the optical quality of the eye during the month of duration of the study compared to baseline or between eyes using either MPS. NIBUT data showed a drop in tear stability from baseline at the end of day 1 and day 30 with both solutions. Burning sensation at insertion was significantly higher at 1 month visit compared to day 1 visit for Biotrue (p<0.05) while end-ofday dryness worsen similarly with both solutions after one month. However, overall satisfaction did not change significantly over the month of lens wear despite a drop below 8 out of 10 rating for Biotrue. Conclusions: Both MPS solutions evaluated showed a good performance regarding objective measures of dehydration, tear stability and subjective performance when combined with a silicone hydrogel contact lens. Commercial Relationships: Jose Manuel Gonzalez-Meijome, PARAGON VISION SCIENCES (C); Ana Carla da Silva, None; Daniela Lopes-Ferreira, None; Helena Neves, None; Antonio Queiros Pereira, None Support: None Program Number: 6121 Poster Board Number: D942 Presentation Time: 8:30 AM - 10:15 AM In Vitro Dehydration of Daily Disposable and Silicone Hydrogel Contact Lens Materials Hendrik Walther, Lakshman Subbaraman, Lyndon W. Jones. CCLR, University of Waterloo, ON, Canada. Purpose: To investigate the in vitro bulk dehydration of various daily disposable (DD) and silicone hydrogel (SiHy) contact lens materials. Methods: Four conventional hydrogel (CH) DD (hilafilcon B, nelfilcon A, omafilcon A, etafilcon A), four SiHy DD (delefilcon A, narafilcon A, narafilcon B, filcon II 3) and seven SH frequent replacement (FR) (balafilcon A, lotrafilcon A, lotrafilcon B, comfilcon A, enfilcon A, senofilcon A, galyfilcon A) contact lenses (n=3) were removed from their blister packs and dehydration analysis was performed gravimetrically (Sartorius MA 100H). Wet weights were measured immediately after removing the lenses from the blister pack and dry weights were determined after lenses were dried for 2 min, using a 600W microwave. In addition, lens materials were continuously assessed for water loss over a 20 min Copyright 2012 by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. For permission to reproduce any abstract, contact the ARVO Office at [email protected]. ARVO 2012 Annual Meeting Abstracts time period at 22°C and 34°C. Results: There was a significant reduction in the water content (WC) over time for all the tested lens materials (p<0.01). Overall, SiHy lenses exhibited slower rates of dehydration than CH lenses. Among the DD lenses, delefilcon A (the DD lens with the lowest WC) displayed the lowest dehydration (31.9±1.7% at 22°C and 29.4±0.8% at 34°C). The higher WC materials showed the highest amount and fastest rate of dehydration (p<0.01). Among the SiHy FR materials, lotrafilcon A showed the least amount (23.3±2.9% at 22°C) and slowest rate of dehydration, although it was not statistically significant (p>0.05) compared with lotrafilcon B and senofilcon A. Comfilcon A (FR SiHy with highest WC) exhibited the highest amount (41.3±0.9% at 22°C) and fastest rate of dehydration (p>0.05). There was a good correlation between measured and manufacturer quoted values for WC (R2=0.99). Conclusions: Bulk dehydration rates of contact lenses are closely related to the initial WC of the material. Lens materials with a higher WC dehydrate more and faster than low WC materials. Increasing the ambient temperature leads to a reduction in the rate of dehydration for some lens materials. Further work is required to relate these in vitro dehydration rates to dehydration rates in eye. Commercial Relationships: Hendrik Walther, CIBA VISION Corporation (F); Lakshman Subbaraman, CIBA VISION Corporation (F); Lyndon W. Jones, CiBA VISION Corporation (F) Support: CIBA VISION Corporation Program Number: 6122 Poster Board Number: D943 Presentation Time: 8:30 AM - 10:15 AM Differential Surface Friction Analysis of Silicone Hydrogel Contact Lenses Treated with Block Co-Polymer Multi-Purpose Solutions Peter Maziarz, III1, X. Michael Liu2, Charles P. Lusignan2, Mohinder M. Merchea3. 1 Research & Development, Bausch + Lomb, Brockport, NY; 2Research & Development, Bausch + Lomb, Rochester, NY; 3Bausch & Lomb, Rochester, NY. Purpose: To understand whether the immersion of silicone hydrogel (SiHy) contact lenses in multipurpose solutions (MPS) using different block co-polymer surfactants impacts lubricity, expressed as the kinetic coefficient of friction (CoF). CoF is a system property that may be an important factor related to in-vivo comfort. It may be influenced by the MPS used, as well as, the lens properties (e.g. surface roughness, surface energetics, and rheology). Methods: Two commercially available multipurpose solutions, MPS A (renu fresh™) or MPS B (PureMoist™) and two SiHy lenses, lotrafilcon B (AirOptix Aqua), and senofilcon A (Acuvue Oasys) were studied. SiHy contact lenses were removed from the blisters, rinsed, and soaked in a large excess of stirred Borate Buffered Saline (BBS) overnight to remove the packaging solution. Subsequently, lenses were equilibrated in MPS A or MPS B for 24 hrs. CoF was characterized with a CSM Nanoscratch Tribometer equipped with a custom-built lens holder. The samples were oriented apex-down in 0.75ml of MPS spread over a Kapton® substrate. CoF was measured under a 30 mN normal load at a speed of 5 mm/min. Multiple data points (n=5), using samples of each lens, were analyzed to determine a mean value and standard deviation. Results: CoF was calculated as the ratio of the lateral force (pull) to the normal force (weight) applied to move the lens relative to the Kapton® at a constant speed. Kinetic friction (motion at constant speed) is different than static friction (incipient motion) and we report only kinetic friction values. The mean (± 1SD) CoF of lotratfilcon A with MPS A and MPS B respectively were 0.06 ± 0.01 and 0.05 ± 0.02. The mean (± 1SD) CoF of senofilcon A with MPS A and MPS B respectively were 0.04 ± 0.03 and 0.03 ± 0.02. There was no statistically significant difference in CoF between MPS A and MPS B for either lotrafilcon A (t-test, p≥0.15) or senofilcon A (t-test, p≥0.57). Conclusions: Although the MPS are formulated with different block copolymer surfactants for improved wettability and lubricity, this study demonstrated that no statistically significant difference (P>0.15) was observed in lubricity between SiHy lenses treated in MPS A or MPS B, under the applied experimental conditions. Further study is warranted to understand the impact of specific surfactants in MPS formulations on in-vivo SiHy lens comfort. Commercial Relationships: Peter Maziarz, III, Bausch + Lomb (E); X. Michael Liu, Bausch + Lomb (E); Charles P. Lusignan, Bausch + Lomb (E); Mohinder M. Merchea, Bausch + Lomb (E) Support: None Program Number: 6123 Poster Board Number: D944 Presentation Time: 8:30 AM - 10:15 AM Differential Contact Angle and Protein/Lipid Deposition Profiles On a Novel Daily Disposable Contact Lens Material Mohinder M. Merchea, Patricia S. Harmon, E. P. Maziarz, X. M. Liu. Bausch + Lomb, Rochester, NY. Purpose: To assess the surface wettability and deposition characteristics of a novel CL material compared to commercially available daily disposable contact lenses using sessile drop contact angle and chromatographic techniques. Methods: The sessile drop contact angle was measured by dispensing a 0.6µL droplet of water onto a blotted anterior lens surface of a novel lens material, narafilcon B (AV TruEye) and etafilcon A (AV Moist). The contact angle was measured at two different points on each lens, resulting in four to six data points for each type of lens in each experiment. Lenses were analyzed both directly out of the packaging solution without rinsing, as well as after being soaked for 18 hours in an artificial tear fluid (ATF) containing common lipids and proteins to simulate lens wear. Quantification of lipid and protein deposits on the lenses soaked in the ATF was performed using GC and HPLC methods. Results: The test lens material demonstrated a more wettable surface based on a statistically significantly lower sessile drop water contact angle than both narafilcon B (p = 9.60 x 10-5) and etafilcon A (p = 5.88 x 10-6) directly out of the blister. After soaking in ATF, the test lens material had a statistically significantly lower contact angle than narafilcon B (p = 2.34 x 10-3) and etafilcon A (p = 6.25 x 10-6). The test lens material also demonstrated the lowest overall deposition level after overnight exposure to an ATF. GC and HPLC demonstrated 13 µg/lens combined lipids and proteins were deposited on the test lens material, which is statistically significantly lower than the 90 µg/lens (p = 7.39 x10 -6) deposited on narafilcon B and 33 µg/lens (p = 2.81 x10-5) deposited on etafilcon A. Conclusions: Based on sessile drop contact angle analysis, the test lens was statistically significantly more surface wettable than either narafilcon B or etafilcon A. The test lens also had statistically significantly fewer combined lipid and protein deposits after being soaked in an artificial tear fluid for 18 hours than either the narafilcon B and etafilcon A. Lower total deposition on lenses may contribute to lower contact angles and enhanced wettability and comfort at end of day. Commercial Relationships: Mohinder M. Merchea, Bausch + Lomb (E); Patricia S. Harmon, Bausch + Lomb (E); E. P. Maziarz, Bausch + Lomb (E); X. M. Liu, Bausch + Lomb (E) Support: None Program Number: 6124 Poster Board Number: D945 Presentation Time: 8:30 AM - 10:15 AM Study Of Novel Chitosan-coated Contact Lens As An Equivalent Substrate For The Therapeutic Delivery Of Rabbit Limbal Epithelium Xiao-Wei Tan, Donald Tan, Roger W. Beuerman, Jodhbir S. Mehta. Singaopore Eye Research Institute, Singapore Eye Research Institute, Singapore, Singapore. Purpose: To determine the efficiency of chitosan (CS) coated etafilcon A contact lens, as a substrate and carrier for rabbit limbal epithelial allograft. Methods: Chitosan was coated on contact lens surface via polydopamine crosslinking. HCET cells were seeded on the surface of contact lens to study the cell attachment rate. Rabbit limbal epithelial tissue explants were co-cultured with 3T3 feeder cells on the CS-coated contact lens. The cell attachment and cytokeratin expression profile of rabbit epithelium was determined by light microscope and immunostaining. Tissue equivalents were tracked by DII and delivered to the surgically injured host rabbit to reconstruct the ocular surface. Cornea epithelium recovery, grafted cell proliferation, migration and differentiation were determined by slit-lamp examination and immunohistological analysis. Results: CS-coated contact lens supported HCET cell attachment. Rabbit limbal epithelial cell proliferate and differentiate on the CS-coated contact lens in a coculture system. Epithelial cells are able to form multilayer on the CS coated lens with strong immunoreactivity to CK3, CK12 and connexin 43. Moreover, CScoated contact lens support the rapid delivery of epithelium layers onto the rabbit cornea. Grafted cells are proliferating (P63+ Ki67+) and differentiated (CK12+ Connexin43 +). Conclusions: We modified the biocompatible CS-coated bandage contact lens to support the attachment, proliferation, delivery, and differentiation of rabbit limbal epithelial cells. This technique may be useful for the efficient delivery of the human corneal tissue equivalent to treat the patients with severe ocular surface diseases. Commercial Relationships: Xiao-Wei Tan, None; Donald Tan, None; Roger W. Beuerman, None; Jodhbir S. Mehta, None Support: SHSC R834 Program Number: 6125 Poster Board Number: D946 Presentation Time: 8:30 AM - 10:15 AM Measuring The Kinetics and Activity of Adsorbed Proteins: In Vitro Lysozyme Deposited Onto Contact Lenses Over Short Time Periods Brad Hall1A, Lyndon Jones1A, James A. Forrest1B. ASchool of Optometry, B Department of Physics & Astronomy, 1University of Waterloo, Waterloo, ON, Canada. Purpose: To develop a process to measure the biological activity of an intact layer of adsorbed lysozyme at the surface of hydrogel contact lens materials. Methods: We use this technique to measure the time dependent amount and activity of adsorbed lysozyme on a number of commercial contact lens biomaterials during the first 2 hours of protein interaction with the material surface. The quantity of adsorbed lysozyme is measured using standard radiolabeled protein. The activity of the surface adsorbed protein is measured using a standard micrococcal activity assay, with extra steps to distinguish between protein on the surface and protein in solution. We use the measured quantities in our experiment Copyright 2012 by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. For permission to reproduce any abstract, contact the ARVO Office at [email protected]. ARVO 2012 Annual Meeting Abstracts to estimate a total layer activity. Results: The amount of active protein is essentially independent of the total protein, and is similar to what one would expect from monolayer coverage. We calculate the amount for a theoretical monolayer of lysozyme on a contact lens to be 692-1035ng, depending on the orientation of lysozyme, and thus can calculate a percentage of active lysozyme in a surface layer for each lens type. The percent of active lysozyme for senofilcon A, lotrafilcon B, and comfilcon A were 3-4, 4-5, and 2-3 percent respectively. Balafilcon A had the highest percent activity in a surface layer for all the silicone hydrogels tested at 30-45 percent. Etafilcon A was the only conventional hydrogel tested and showed 78-117 percent activity in a surface layer of lysozyme, which was the highest of all lens materials tested. Conclusions: This study has established an effective technique to evaluate the activity of an intact lysozyme coating on a biomaterial. Our results show that protein can rapidly deposit and can rapidly lose its biological function on biomaterials in as little as 10 seconds of protein-surface interaction. Despite the simplicity of the technique, to the best of our knowledge this is the first report quantifying the biological activity of an intact layer of surface-adsorbed protein on hydrogel materials. transparency, strength and potential for drug delivery. Commercial Relationships: Marcia W. Patchan, Cellulose-Based Hydrogels and Methods of Making Thereof (P); Jenna Graham, Cellulose-Based Hydrogels and Methods of Making Thereof (P); Zhiyong Xia, None; Jeffrey Maranchi, Cellulose-Based Hydrogels and Methods of Making Thereof (P); Jennifer Elisseeff, Cellulose-Based Hydrogels and Methods of Making Thereof (P); Oliver D. Schein, None; Morgana Trexler, Cellulose-Based Hydrogels and Methods of Making Thereof (P) Support: USAMRMC Grant W81XWH-09-2-0173 Commercial Relationships: Brad Hall, None; Lyndon Jones, None; James A. Forrest, None Support: Natural Sciences and Engineering Research Council (NSERC) of Canada Program Number: 6126 Poster Board Number: D947 Presentation Time: 8:30 AM - 10:15 AM Regenerated Cellulose Hydrogels with High Optical Transparency and Mechanical Strength for Corneal Applications Marcia W. Patchan1, Jenna Graham1,2, Zhiyong Xia1, Jeffrey Maranchi1, Jennifer Elisseeff2,3, Oliver D. Schein3, Morgana Trexler1. 1Milton Eisenhower Research Center, Johns Hopkins University Applied Physics Lab, Laurel, MD; 2Biomedical Engineering, Johns Hopkins University, Baltimore, MD; 3Ophthalmology, Johns Hopkins Wilmer Eye Inst, Baltimore, MD. Purpose: To optimize the mechanical and optical properties of regenerated cellulose hydrogels for corneal applications. Methods: Cellulose hydrogels were prepared by activating two grams of cellulose powder in 100mL N,N-dimethylacetamide (DMAc) with stirring for 24 hours, after which 8g of LiCl was added with continued stirring and gentle heating until the solution became clear. The resulting solution was poured into silicone molds of the appropriate dimensions for mechanical testing or onto glass plates to obtain thin sheets. The gelled samples were gently washed in water to remove excess LiCl/DMAc and stored in water prior to characterization. The gels were characterized for tensile strength, tear strength, crosslinking density, crystal structure, optical transparency, and biocompatibility. Results: Cellulose hydrogels were prepared from different types of cellulose (cotton, plant, and bacteria derived). After initial characterization, the cellulose types with the highest tensile strength and optical transparency (Figure 1) were further characterized based on synthesis parameters (cellulose concentration, gelation humidity, and stir time). Conclusions: Cellulose hydrogels with optimized material properties can be synthesized by controlling the gelation humidity and cellulose concentration. These materials show promise for corneal applications due to their biocompatibility, Copyright 2012 by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. For permission to reproduce any abstract, contact the ARVO Office at [email protected].