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Special Cases for CL Toric SCL SCL Toric Evaluation When we select a patient for soft toric lens fitting it is usually because they have low to moderate amounts of refractive cylinder in their prescription. When we examine the amounts of cylinder available in standard toric lenses, it usually falls between -0.75 and -1.75 diopters. Custom soft toric contact lenses are available in a wider variety of both sphere and cylinder powers, but are fit with much less frequency due to increased costs and decreased successes. When evaluating whether a patient may be an appropriate candidate for a soft toric contact lens fitting, the patient’s refractive error must be assessed. Remember that in standard parameters the only cylinder powers that are available to us classically fall between -0.75 and -1.75 diopters cylinder. Additionally, most standard soft toric contact lenses are only available in sphere powers between +4.00 and -6.00 diopters. The OAD of the lens must also be taken into consideration. Soft toric contact lenses have a tendency to be larger than most soft sphere contact lenses. This increased size helps aid in stabilizing the rotation of the contact lens. However, in individuals with small palpebral fissures, this increased OAD may become an issue. Soft toric contact lenses usually come in diameters between 14.0-15.0mm. Some of the other special features that we have become accustomed to with soft spherical contact lenses are available to us with soft toric lenses as well, but on a limited basis. For example, soft toric lenses are available in cosmetic tints and opaque tints. Additionally, some soft torics lenses are approved for EW or FW modalities. It should be realized that with every special feature, the total amount of lenses available is diminished significantly. Selection of a Diagnostic Soft Toric Contact Lens With the combinations between each patient on palpebral fissure diameter, BC, sphere, cylinder, and axis, no office can possess trial contact lenses that will perfectly match each patient. Therefore, the following items will help you make some educated choices about what trial lens to select. If you have a choice between two OADs when selecting a diagnostic CL, select the smaller of the two lenses as your first choice. When selecting BC for the initial diagnostic CL select the flatter BC if you have only 2 choices, or select the middle BC if you have 3 choices. When selecting the power of the soft toric CL, pick both the sphere and axis as close to the patient’s refraction as possible as these two parameters are the most important. The value of the cylinder power is the least important value in trial lens selection. As long as all the other parameters are considered first, then select the cylinder power as close to the patient’s refraction as possible. Soft Toric Contact Lens Fit Assessment Although many of the rules applied to soft toric contact lens fitting are the same as soft sphere contact lenses, some additional items are also evaluated. Because all types of soft toric contact lenses use some method od stabilization, the diagnostic contact lens should be allowed to equilibrate for somewhere between 10-30 minutes before a thorough evaluation of the lens performed. However, an initial gross observation of the diagnostic lens should be made shortly after application to determine if the coverage, centration, etc is at least in the ballpark. If the diagnostic lens is grossly inappropriate, then further evaluation is a waste of time. After the lens has equilibrated, an overrefratction should be performed. A spherocylinder overrefraction to BVA should be obtained as well as a spherical only overrefraction to BVA. After the OR is performed, a thorough fit assessment is completed. As with soft spherical contact lenses, those characteristics of the fit that are evaluated are centration, coverage, MOB, lag, and sag. The criteria for an acceptable fit are the same as that applied to a soft sphere. There are two additional aspects of lens that are evaluated on a soft toric contact lens, these are the characterictics of rotation and stability. Each soft toric lens has markings on it in some location that aids in determining the amount that the lens has rotated or positioned on the eye. o The first step is to locate these markings with the slit lamp. Then an estimation of the amount of rotation is attempted and recorded. If the eye is divided into clockdial increments, rotation of the lens one clock hour represents 30 degrees. With certain slit lamps, the beam of the slit lamp can be aligned with the orientation marks of the toric lens, and the amount of rotation can be directly measured using the protractor device. Recording of the direction of the rotation, either temporal or nasal, along with a drawing is also required. Rotation over 20 degrees is usually considered unacceptable and another diagnostic lens choice should be made. o Stability of the rotation of the contact lens on the eye is also evaluated. It is logical that for a patient to obtain good VA out of a soft toric lens, the lens must maintain the orientation of its cylinder correction at a constant position on the eye. This is why the stability of the lens is important. Ask the patient to give you a full, strong blink while you observe the behavior of the lens behind the slit lamp. The rotation of the contact lens should stay relatively constant even during the blink for acceptable visual performance. Excessive rotation of the contact lens on blink indicates the need for another diagnostic lens. Rotational Stabilizers o Prism “ballast” (watermelon seed effect) 3/4D 2D Not custom ordered Increased prism Increased stabilization for decreased rotation Increased thickness, therefore decreased O2. o Decreased O2 means increased neovascularization. Comfort? Adds a BD affect o Eccentric lenticulation Increased OAD (~15mm) o Back surface toric Stabilization? – all have prism (back and front) Back surface vs. front surface toric Lathe-cut usually back surface toric Molded usually front surface toric When do you prescribe front vs. back surface SCLs? o On the eye, probably not a significant factor. Choose based on other factors. o Double slab-off 2 thin areas Least effective stabilizer? Lids grab onto the thin areas? Most comfortable Made quickly because molded. o Truncation (dinosaur) Problem with stabilization and comfort. o Combination o Large OAD Contributes to lens stabilization Allows for more pronounced thick and thin areas Lens Markings o Base Down Positions Usually at 6 o’clock Scribe mark, three scribes marks, dots Separation of scribe marks o 3 and 9 o’clock markings o How do you quantify rotation? Clock Each hour is 30 degrees Spectacle trial frame Slit lamp housing angle Slit lamp eyepiece reticule Markings cover so many degrees due to magnification. Over-refraction Use the cross-cyl formula. This is the most accurate. o LARS Left add, right subtract Add/subtract to the axis of the subjective rx, not the DxCL. If the diagnostic lens is rotated, then the dispensed lens should be rotated. Ex 1 Refraction: -2.00 -1.50 x090 Diagnostic CL: -1.50 -1.50 x100 Rotation: 10 degrees to the R and stable Order: -2.00 -1.50 x080 o On D-day, the dot should be 10 degrees to the R Ex 2 Refraction: +2.00 -2.00 x180 Diagnostic CL: +2.50 -1.75 x170 Rotation: 10 degrees to the L and stable Order: +2.00 -2.00 x010 o Dot should still be 10 degrees to the L Patient Selection Guidelines o Refractive error Sphere +4.00 tp -6.00D Cylinder >0.75 to <3.00D corneal vs. internal cyl Axis Any, but obliques tend to have worse rotation. o Realistic Expectations Visual compromise vs. RGP or spectacles or refractive surgery. Selection of Brand o DW vs EW vs Tint vs Replacement Schedule Don’t do EW Only order this to make the profile thinner, but don’t use as EW It increases the oxygen, but not as stable. o Availability of Parameters Inventory vs. custom Custom: increased cost and delivery time. o Availability of Warranty/Guarenteed Fit Program Which company gives you least hassle? o Refractive Error High sphere and low cylinder Cyl doesn’t have to be as accurate Go with a thinner lens (O2 permeability more important than stability) Low sphere and high cyl Cyl needs to be accurate Use CL with increased prism Orientation of cyl axis Double slab off- ATR/WTR Prism- Oblique Fitting o Empirical vs. Trial Lens Fitting Fitting without patient in the office. This is done with faraway patients. Trial lens Fitting Selection of Diagnostic CL o Availability of parameters o Selection of BC/OAD BC- avg K OAD- use larger, because it increases the rotational stability. o SPHERE, cylinder, AXIS Choose sphere and axis first. These play more roles in the rotation. With a -2.00 -2.00 x090, choose -2.00 -1.00 x090 Apply lens and allow to equilibrate o 10-30 min o apply BD o teach technique to the patient. Evaluate the fit o Coverage/centration/movement Evaluate rotation/stability (consistency of rotation) o LARS o “Dial lens” Becherer Twist with displacement, should return within 10 blinks. Perform OR (sphero-cyl) o Hints Add + to sphere for lenses with thick profiles. This is due to flexure effects, not TL. Prescribe less cyl than SRx. This does not occur with double slab-off. Ordering a Soft Toric Contact Lens The first step in selecting a soft toric contact lens is to remind yourself of exactly what parameters the lens you want has available. Every parameter and power is not available in soft toric lens design. You will need to refer to Tyler’s Quarterly. Final sphere power can be determined in one of two ways (both of these should correlate). The sphere power can be determined by taking the vertexed sphere power of the refraction or by combining the power of the diagnostic trial lens and the spherical over-refraction (if possible). These two values should be in agreement. To determine the axis of the ordered lens based on the rotation noted on slit lamp observation, if all other characteristics of the diagnostic lens were acceptable, then compensation for the observed rotation is made. The rule that is applied is called , LARS, which stands for left add, right subtract. This indicates that if the lens rotates to the clinician’s left, the amount of rotation is added to the patient’s refractive axis and if the rotation is to the clinician’s right, the value would be subtracted from the patient’s refractive axis, not tha axis of the diagnostic contact lens. CL Correction for Presbyopia Advantages o Dependent on SRx o Motivated- more proactive with healthcare o Follow instructions? o Possess discretionary funds o Decreased corneal and lid sensitivity due to lax lids, therefore increased tolerance. o May have long history of CL wear. o With large prescriptions, there is a better image size and increased periphery. This also means that it could be covered by insurance. Disadvantages o Decreased tear volume/quality due to hormonal changes, etc. o More medications that might dry eye o Fear of CL (or anything touching the eye if never worn before) o Decreased importance of cosmesis o Medication interactions o Decreased pupil size. Therefore, establish realistic expectations Options o Distance CL with near overcorrection (like OTC readers) Most common o Near CL with distance overcorrection (Good for those with a lot of nearwork) o Monovision o Bifocal CL Alternating Analogous to SRx bifocals: 2 segs with 2 powers Lens has a small seg (3mm) and needs to translate With large pupils you can have simultaneous vision Simultaneous See distance and near at the same time (analogous to progressives) Can also get intermediate Produces ghost images and brain chooses which to see. This decreases distance VA a little. o Modified/Enhanced Monovision Modified- 1SV and 1 bifocal CL Enhanced- Can overlap Rxs (Dist/Int and Int/Near) o All options are available with either rigid or SCL Except no translating deisgn in SCL because it is too large to translate. Examples o 1: Distance CL with reading overcorrection Patient 47 requires a +1.50 add 43.75 DS Km 43.75DS -4.25 -0.50 x170 SRv -4.50 DS 43.00/-3.75/SCCO CLRx 43.00/-3.75/SCCO +0.25 -0.50 x170 OR plano DS AA/DS/Avg/C FP AA/DS/Avg/C Prescribe spectacle overcorrection of o OD: +1.75 -0.50 x170 OR + Add +1.50 DS wouldn’t be bad, but with ATR, Rx the cyl for sure. o OS: +1.50 DS o Use near work when wearing CLs o Specify on CLRx for near use over the CL. o Need to specify near PD o 2: Near CLs with distance overcorrection Patient 42- requires a +1.00 Add 43.50 DS Km 43.75/43.25 x180 +2.00 DS SRv +1.50DS 42.75/+2.75/SCCO Dist CLRx 42.75/+2.25/SCCO plano DS Dist OR +0.25 -0.50 x090 42.75/+3.75/SCCO Near CLRx 42.75/+3.25/SCCO -1.00DS Near OR -0.75 -0.50 x090 AA/DS/Avg/C FP AA/-0.50 x180/Avg/C Near OR done at distance. There is no such thing as a near Rx. Prescribe spectacle correction of o OD: -1.00DS o OS: -0.75 -0.50 x090 o To be worn over CLs for driving, distance tasks. o Prescribing the cyl justifies the glasses even more. o This is often done with keratoconics. Monovision One eye fit for distance/ one eye fit for near Simultaneous distance and near #1 presbyopic CL option o only option for those with LASIK o success rate? 80-90% (most successful fitting modality) o Adaptation period? 15 min-1 week depending on the patient Usually occurs within 3 days. Advantages o Can use same fitting philosophies and lens materials (simple) o Can use same lens replacement schedule (all lens types) o Less expensive- same as SV o Good distance, good near Disadvantages o Adaptation problems Near eye is constantly defocused, some patients get over it, some don’t. Give them about 2-3 weeks. If they don’t get it, they wont ever. o Interferes with stereopsis and binocular vision o Glare at night. Some patients will buy a pair of glasses to wear over monovision when driving at night. Offer it if they complain about this. Due to near defocus. Most adapt to this. Don’t fit o Patients who do mostly near or mostly distance work o Patients with reduced VA in one eye (amblyopes) Selection of near eye o Dominant eye for distance (most prevalent philosophy) if mostly distance o Visa versa (dominant eye for near if do mostly near work) o Near lens for placement of vocational (typing) or avocational (car mirror) needs. ; o If one eye has good unaided distance vision- fit other eye for near. o If one eye has good unaided near vision- fit other eye for distance o With RGPs, fit both eyes because they need the same sensation. Near Stereoacuity o Stereo is only needed with very detailed near work, therefore don’t use monovision o Koetting (1970) found 94% of monovision patients had normal stereopsis when age matched. o Christie and Sarver (1971) found little or no loss of stereopsis with adds of <1.00 D o Blake, et al. (1980) reported that a “suppressed” eye may contribute to stereopsis o McGill and Erickson (1988) reported reduction in stereoacuity with monovision. They found that it was a function of the add. Increased add means decreased stereo. Distance Stereoacuity o This is not as important o Back (1987) found that monovision wearers exhibited a significant loss in distance stereoacuity when compared to soft bifocal CL wearers. o Rouse et al. (1988) found that static stereo deficient subjects can use dynamically changing disparities to make depth judgements. Binocularity o Loshin, Loshin, and Comer (1982) found that for adds up to +1.50, binocular summation in contrast sensitivity function was lost for middle frequency and high frequency (high detail). It was retained for low frequency. But, all binocular summation was lost with adds greater than +2.00D. Peripheral Vision o McLendon et al (1968) tested visual field using a 3mm target. They found that there was a decrease in the VF of 0.2 degrees for the eye corrected for near as compared to the field of the eye corrected for distance. But, there was an overall increase of about 5 degrees for CL correction as compared to spectacle correction. o Lit, Stern, and Edrington (1991) found that adds <2.00D had little or no effect on the binocular field of view. Subjects demonstrated a 2-5 degree field compression with adds >2.00D Note: motion detection in the peripheral retina is least affected by blur. Legal concerns of monovision o Harris and Classes (JAOA, 1988) Alternatives need to be explained. Limitations should be presented Have patient sign informed consent Caution against driving or operating heavy machinery during adaptation to monovision Need to instruct patient of adaptation. o Nakagawa (Optom 2000) National Transportation Safety Board (NTSB) determined probable cause of Delta aircrash on 10/19/1996 due to inability of pilot to overcome misconception of airplane’s position relative to the runway due to monovision. o Slutsky, Wang, Edrington (OVS 2000) Pilot’s landing ability not related to distance stereo. Multifocal Rigid CLs Case History o CL History Previous wearer? Likes? Dislikes? Success? RGPs? Monovision? o Medical History Medications that can affect CL wear? o Occupational and Avocational Needs Computer use? If it is more than 30% of their time, you may want to consider aspheric lenses, which may increase the intermediate vision. o Motivation and dedication Return for F/U? very important! It can take up to 6 weeks to fit some lenses. Ask for their commitement. o Awareness of cost About $300. Doubles for SCL. Premium lenses require a premium price. Patient education must reinforce this. CL Fitting o Refraction Push the most plus distance vision. This makes the add work better. Over-minusing a patient at distance causes decreased near Vas. o Position of eyelid We don’t want any bug eyes or squinty eyes. o Corneal Curvature with keratometry Topography is an overkill. o Pupil Size CL depends on the size of the pupil. Concentric or Annular Bifocal CL o Can use regular fitting philosophy Assuming that the lens centers well. Can fit up to 6D steeper o Central zone should be smaller than pupil Usually 3mm or less. Some larger if utilize both designs o Usually fit as a simultaneous design, can be fit as an alternating design o If designed as an alternating bifocal Need more movement (translation) Need larger central zone- so no simultaneous vision o Advantages Not dependent on translation o Disadvantages ~50% light available at each viewing distance, meaning decreased VA Symptoms of glare, haze, halos, ghost images because the patient sees 2 images at once. Dependent on pupil size. Aspheric Multifocal CL o F1 or F2 can be aspheric Majority are F2 Made via blending various radii of curvatures (add effect by adjusting TL) o Higher eccentricity = higher add Gradual increase in plus towards the edge. Intermediate vision available o Simultaneous or alternating? Dependent on eccentricity of lens Pupil size dependent o Usually fit steep centrally; can be lid-attachment- Hi-Rider To get add effect and well centered. FP = AC o Lens analysis BC- tilt radiuscope Looks like warp if youre not on the center. No distinct zones CLP- Schiener’s disc Pinhole it or use a smaller aperture Shift sideways to read add. Eccentricity Add Effect 0 (circle) None 0.1-0.9 (ellipse) Small (+1.00) 1.0 (parabola) Medium (+2.00) >1.00 (hyperbola) Large (+3.00) This does not have the same result for every patient, because patients have varying e values. E Steeper than K Near Power Received 0.4 0.5F-0.5S 0.75D 0.6 1.5-2.75S 1.25D 1.0 3-3.5Steep 2.00D 1.4 4.75-6S 3.00D Increased e means increased near power, also steeper. o Advantages Not as dependent on translation Intermediate vision More like “natural vision” Early presbyopes o Disadvantages Add effect often not sufficient (decreased VA at near) Limited add capabilities based on parabolic/hyperbolic manufacturing Add dependent upon pupil size. Critical near vision needs “Swim” Spectacle blur due to edema Fused Crescent Bifocal- contains seg o Distance vision in the superior portion of the lens. Near vision is in the inferior portion. o The lid must hold the lens in place. When the patient looks down, the lid catches the lens, the lens moves, and the pupil looks through the inferior portion. Doesn’t work well for those with floppy lids. Look at where the lower lid hits the eye. If it is >1mm higher or lower than the limbus, the lens wont work well for this patient. Most people fall within these parameters though. o A little nasal rotation is alright since the eyes converge to read. Temporal rotation is bad. o Fused crescent o o o o Add has higher n Prism ballasted Most common So rotated properly Usually 1-3pd Add 0.10mm to center thickness for each 1pd. Selectively thin area you desire to position under upper temporal portion of the eyelid (watermelon seed effect) Truncation may help stabilize rotation. It also drops the lens Shave off the inferior 2mm. Lower limbus should be tangent to lower lid (+/-0.1mm) Segment Lens must catch on lower lid in downgaze Measuring the seg height Measure distance from visual axis to lower lid o Slit lamp reticule o Penlight at 20 inches while patient fixates the light. o Subtract 1.3mm from the lower lid to visual axis measurement o –or- key off diagnostic lens. Alternating design In theory Does BF drop fast enough so patient can see distance quickly? Don’t want to see both at the same time. Advantage Doesn’t block distance Disadvantage Smaller reading portion Who do you fit? Patients that want them Good for higher adds Previous wearers (don’t go to simultaneous) Not monovision patients Types Many segment designs available: round (centered, decentered), executive, upsweep, crescent, offset lenticular. Tangent streak (Fused Kontacts of Missouri)- trifocal Lifestyle Hi-Rider Aspheric Fit flat, vs steep like other aspherics. Fit as lid attachment. It behaves like a translating lens. It is a multi-aspheric back surface multifocal with a progressive addition design. There are 2 kinds: o Low add and high add. o Diagnostic set has a single aspheric surface. 10 lenses made of the SGP II material. The EQ values range from 7.3-8.2mm and have 9.0 and 9.5 OADs. The 9.5 is better to ensure lid attachment. o High add has the same back asphericity, but an additional front aspheric surface to increase the add. (A +2.50 add is still rare). Fitting o Determine the patient’s flattest corneal reading o Choose the EQ trial lens that is closest to this. o Allow the lens to settle. It should assume the superior position. 1/3 of the lens will be under the superior lid with you looking through the distance area during primary gaze. o The lens should look flat when looking at the FP (about 0.5D) o If this does not work, try another lens that is 0.1mm flatter. o You should not go more than 2 steps flatter before deciding that it doesn’t work. o Performa sphero-cylinder OR. Advantage o It will work or not. There are no ifs, ands, or buts. Disadvantage o You will get an ortho-K effect, therefore this needs to be the primary mode of eyewear. You cannot be a partial lens wearer with this. The corneal topography will change. Case Example o A 48 yo female RN with RGP monovision is not happy. This means that she either 1. loves bifocals or 2. will love monovision when you refit her. SO, whatever you do will help make the patient decide. o Refractions OD: -3.50 -0.75 x097 OS: -3.50 DS Add +1.75 20/20 o Ks: OD: 44.67 / 43.25 x180 Flat: 43.25 = 7.80 OS: 44.37 / 43.50 x180 Flat: 43.50 = 7.76 o Trials: 7.80/-3.50 OU o OR: OD: +0.25 _0.50 x090 OS: +0.50 DS o VA at 40cm: 20/25+2 – OU o FP: AT x 0.75D/ Lid Attachment – OU o F/U in 2 weeks and the patient complained of the CL dropping after each blink. This caused an unstable VA. A change to an EQ of 7.90 was made and the CL power change accordingly. o This is very common because it is seen in real situations. Poor candidates o Patients with poor lid tone o Pupils greater than 5mm in ambient lighting o Flat (<4100) and Steep (>45.00) corneas. It would not be able to tuck under the lid. Unilens RGP Aspheric Fit like your typical aspheric CL Patient selection o Good motivation and realistic expectations o Add up to 2.00D o Up to 2.50 WTR or 0.75ATR so the lens can center. o Current RGP wearer o Patients with habitual prescriptions. (Myopes better candidates) Fitting o The BC should be set 1.50D steeper than K o OAD BC OAD Less than or = 7.2 9.2 7.25-7.95 9.5 Greater than 8.0 9.8 A flatter BC requires an increased OAD to “stick.” o Fit centered, mid-peripheral alignment and slightly central pooling. If decentered, choose a steeper BC and look for improvement. o With aspheric lenses, do not call it AT or AC. Talk about pooling. o Evaluate: With each blink does it recenter? With each blink do you have adequate tear flow? OR Check NVA Compare CLP by OR to empirical CLP calculations o DxCL CLP + ORv = SRx + (-1.25) Anticipate more minus power, because it is fit steep on purpose. o Double check the near VA with the final Rx o With aspheric contacts, it is not rare to order increased add to even the +1.25. Blanchard Essentials Aspheric back surface Patient selection o Existing RGP wearer o Well motivated, reasonable expectations o Presbyopic patients requiring sharp distance and near o Adds up to +2.75 (2.50 more realistic) o Up to 2.50D WTR and 0.75D ATR o Avoid very steep (>47D) or very flat K (<40D) readings o Avoid puils in excess of 5.5mm Comes in 3 series: 1, 2, and 3 o Each has a different power profile. o Series 1 has a slower glide in power than series 3 which has a steeper and quicker glide in power. Series 1 is better for new presbyopes (+0.75 to +1.25 add), Series 2 (+1.25 to +1.75 add) and series 3 (+1.75 and up). o It is not unusual in these aspheric bifocals that you order a higher potential add power than what the patient needs. For example, patient needs +1.25 add, youll probably stick them in a series 2 lens, even though they are on the cusp of a series 1. o The company supplies a BC and OAD selection chart that the company recommends. Typically these fitting guidelines have been put together by many practitioners who have fit many of these lenses. Lens position and movement o The ideal fit will be superior central (upper lid attachment) with a NaFl pattern that demonstrates alignment along the flattest corneal meridian. o This lens is very similar to a lifestyle hi-rider. The lens position is not perfectly centered. It is more of a slight lid attachment fit. So it is an aspheric lens that behaves more like a simultaneous/translating hybrid. Evaluation o Perform OR with loose trial lenses to determine the final distance Rx. o Expect the final Rx to be -0.50 to -1.00D more than the existing CLRx. o Place the OR in a trial frame and evaluate the transition form distance to near. o If the OR leads to acceptable distance but stinky near, rethink the BC or series design. Disadvantages o The company is on the east coast, so there is a 2 week delivery time. o Pretty pricey. ($140/lens) Menicon SF-P Bifocals- Decentered target or crescent seg. Fluoroperm ST- Paragon Vision Science Solitaire- Tru-Form A segmented lens. The distance segment is cut above. It looks like an executive bifocal. The plus bottom portion acts like a carrier. It is like a tangent streak lens which has an executive ledge and is thicker on the bottom because of prism and truncatrion, so the tangent streak is more uncomfortable. Also, because it is thicker inferiorly, you get some physiologically breakdown of the inferior cornea. This is rarely seen with the solitaire lens. A prismatic reading lens with a monocentric distance seg cut on the top part of the lens using the same visual axis. Because it is bottom heavy, you do not need as much prism to stabilize it nor do you have to truncate it. This provides for better comfort. Usually 2D of prism is sufficient, regardless of the CLP. A good clinical tip is that you should always include 0.250.50D more prism that what the manufacturer recommends. Solitaire II has an intermediate corridor. The only issue with this is that centration is of utmost importance. Fitting o BC selection Very close to our fitting philosophy of K 0.75 (maybe 0.25-0.50 steeper) Corneal Cyl BC Spherical 0.25 flatter than K 0.25-0.75D On K 1.00D- 1.75D On K to 0.25 steeper than K 2.00D-2.25D 0.50D steeper than K o Optic Zone Size OZ is 83% of the horizontal diameter before truncation. Ex OAD 9.4 OZ 7.8 OAD 9.0 OZ 7.5 o Seg placement and amount of prism will be the toughest decisions. o The visual performance is superior as long as the seg is at the right location and is stable. Troubleshooting o Lens lags too long after blink Thin upper edge Increase prism Loosen lens, or order flatter BC Lower seg while increasing the diameter of the new lens. o Difficulty reading Patient not orienting head properly Lens too tight causing minimal movement, loosen lens or order flatter BC Not enough clearance for vertical displacement. High segment with smaller diameter. Lower lid does not support lens, truncate to produce more contact with lid. Order new lens with higher seg. o Patient has trouble at distance If lens is not at lower lid, then loosen, order flatter BC or lens with more prism. If lens positions properly, then seg is too high. Truncate or order lens with lower seg. If lens is large, reduce diameter, and/or truncate. o Patient experiences flare Larger OAD and/or OZ for larger viewing field. Lower seg to give larger viewing field. Truncate or re-order. Patient has large pupils. o Lens position too high Lens too tight, flatten Add more prism on new lens order. Diameter too small. If lens has truncation, order new lens without or reorder larger lens. o Presbylite Intermediate blended Like a progressive o Fitting Use diagnostic lenses Determine BC o o o o Evaluate stability Determine seg height Use a DxCL of an appropriate BC, find where the seg height sits. In straight ahead gaze, the top edge of the seg should ride at the lower edge of the pupil in ambient illumination. Some manufacturers say to go about 1/3 into the pupil, but most patients don’t like that. We are looking for good stability of the inferior seg and good recovery after blinking. Record amount of prism needed. Best Case Scenario Better with RGPs Normal eyelid position should be within 1mm of the limbus. If the lower lid is too high, it causes the segment to be in the way. If it is too low, it means that the lens will not be shoved up for near acuity. Average to small pupils are better. Too large means that the vision runs into the near segement. Low WTR toricity (less than 2D). We want to lens to ride a little low, so WTR allows us to do that. Rocking high means the seg is in the way. Greater than 2D decreases comfort. High tone lid. Patient wants or is already an RGP wearer. Lens Analysis BC- radiuscope, should be spherical (watch out for warp) CLP- use small aperture lensometer or blacken area of lens not being measured with a visavis marker. Prism- use lensometer. Needs to be in the BD position. Seg Ht- use 7x If truncated, measure from the ideal bottom. It is more ideal if rotated due to convergence. Advantage Crisp VA at both distance and near Disadvantage Unable to meet vocational or avocational needs for upgaze Cant do adds on top (no double D) Not good for those with flaccid lids. Don’t fit Monovision patients Those with a lot of N Loose lower lids Multifocal Soft CLs Translating Alternating Image Designs o None in soft lens design Simultaneous Image Designs o Types Concentric or annular segment Generally this works better in a soft lens modality, although it can work in RGPs. It is a bull’s eye design. Distance and near is seen at the same time in each eye. A common complaint is a 3D effect when looking at something flat. This makes sense because the near image is clear, then at the same time the distance image is hovering right there too so it is perceived as one object with the same one right above it. Make the patient aware of this. Ciba, AV, CV, and Unilens are some brands that offer this kind of lens. Unilens actually lets you choose a certain size for the center zone. A smaller near zone on the distance eye and a larger near zone for the near eye increases the success rate. Annular o Centrad (center-distance) o Reverse centrad (center-near) Aspheric Posterior o Behaves similar to PALs. o Soft and rigid o Posterior aspherics have a spherical front surface o Increased power in the periphery. Much variety. o Types Hydrocurve II (WJ)- CD Occassions (B&L)- CD CV Frequency 55 MF- CD and CN Sunsoft MF (Sunsoft)- CN Now FRP Sunsoft Additions. Anterior o Soft CL Types Unilens (Unilens)- CN Softsite (Unilens)- CN AberCon N, N250, D (World Optics, Inc.)CN o RGPs No add power added with these. The more plus power require, means that one can make both the front and the back aspheric. Start with back aspheric, and can add to the front if more plus required. Pupil size dependent. Diffractive Diffrax (RGP) or Hydron Echelon (OSI/American Hydron) Uses prism to create two images Seen more in Europe Modified monovision SV in one eye/ bifocal in the other Enhanced monovision 2 bifocal of overlapping distance correction o Brands AV Bifocal Simultaneous vision, concentric ring design (5 concentric rings) Power range +4.00 -6.00 in 4 add powers o The boxes are marked with 2 powers. The distance and add. BC 8.5, OAD 14.2 VT, inversion mark (123), UV block Often require increased minus. So thin that not so sensitive to inversion. Relatively good distance vision. Near is not so great. 2 week less Focus Progressives Highly concentrated add power in a compact central near zone. Large peripheral distance area 2 week disposable modality 8.6mm, 8.9mm BC OAD 14.0mm Vifilcon A, 55% +6.00 -10.00 in 0.25D steps Single progressive add; effective range up to +3.00 Packaging in 6-packs Initial lens power selection o SE + (Add/2) o Example SRx = -2.00 with a +1.50 add -1.25 o a chart is available for this to be easier. condensed 2mm aspheric add zone right in the middle of the lens. Since the add portion is small, distance area is larger. CV Frequency 55 MF Methalfilcon A, 55% water, FW lens BC 8.7, OAD 14.4 +4.00 -6.00 Add powers of +1.50, 2.00, 2.50 D lens (dominant), and a N lens (non-dominant eye) Modified monovision lens. Aspheric design o Fitting Use DxCLs for BC determination Lenses must center well. This is very important. Can go steeper to center better for RGPs and can sacrifice the fit a little for better centration. Allow the lens to settle at least 20-30 min. Perform trial frame or loose lens OR for BVA at 6m. Don’t use the phoropter. Make sure the patient is M+BVA Visual comfort more important than Vas. Test near VA with the same OR Who should I fit with ? o Motivated o Realistic expectations o “Spherical” subjective refractions Adaptation worse for toric bifocals o Hyperopia greater than 1.00D o Myopia greater than 2.00D o No risk to try (Greater profit margin) Best case scenario o Large pupils to cover as much optics as possible. o No critical vision tasks. o Accept contrast loss o Stable light environment o Lenses must center o Works best with soft lens design in general. Disposable Soft Multifocal CLs o Acuvue Bifocal Concentric design of 5 alternating zones of D/N “Pupil smart” because size independent 1 BC SRvEDS- adds in 0.50D steps Loose lens OR +/- 0.25/0.50. No phoropter. This creates an artificial environment Adjust D/N Rx as appropriate o B&L Aspheric Soflens MF 2 BC comes in high and low add o Ciba Progressives Aspheric center near Also daily disposable 1 BC ½ add + SRvEDS loose lens OK Efficient, comfort, handling o Cooper Frequency 55 MF Aspheric Centrad/reverse philosophy D and N lens 1 BC SrvEDS D lens: dominant/ N lens: non-dominant 3 adds: +1.50, 2.00, 2.50 Seven Deadly Sins of Bifocal CLs Pick the wrong patients o Don’t pick patients that are too meticulous about their vision, someone with varied tasks, or too much cyl. o Don’t be afraid to tell the patients that they are not good candidates. Omit trial lens fitting o See how they center, move, translate, recover, and perform. o Push max plus in the distance. Don’t overminus. o Determine what the reading distance for the patient is. Use that as the distance. o Don’t worry about 20/20. just make sure the patient has the vision to do everything that they need to do. Judge fit of the lens based on MOB alone Incorrect distance endpoint Over and under prescribing add power Not considering binocular performance Chasing perfection Aspherics Aspheric Uses o Reduce spherical aberration Decreases the CLC. For some, it therefore appears sharper or clearer. No change in OR cyl. o Improve fitting characteristics It contours to the eye. Easier A and R o Provide add effect for MF designs RGP Blanchard Essential RGP MF Boston Multivision Lifestyle GP MF Unilens SCL SV o Coopervision Frequency 55 Aspheric MF o Ciba Vision Focus Progressive Aspheric center add (~2mm) o Unilens 38 Front aspheric with near center Aspheric Design o Front surface aspheric Reduces spherical aberration Corrects residual astigmatism Additional add effects for MFs (a little) o Back surface aspheric Continuous across entire F2- contours the cornea. Aspheric periphery (center spherical)- like a heavy blend Provides an add effects (“Main”) Continuous cornea Advantages o Better corneal alignment Yeah, but you don’t want it too good (poor a and r) o Better centration On toric corneas (decreased centration with spherical corneas) o Decreased spherical aberrations o No junctions Increased blends, although nothing wrong with junctions o Decreased flare Increased OZ because increased blends o Increased comfort Only during adaptation. No long term effects o MF effect, especially with new presbyopes o K-cone and irregular corneal fittings Not good, because we don’t know the back curves, therefore we cannot modify in-office. Disadvantages o Difficult to fabricate/polish/reproduce Uses a CNC (computer numeric control) lathe Cuts well, but the problem comes with polishing. o Difficult to verify Use small aperture for CLP Increased aperture means increased plus power Tilt radiuscope to determine e value o Variable vision Induce residual astigmatism with decentration Smaller “spherical” OZ with aspheric periphery might get only 4mm center. o Lens decentration Means less VA due to increased plus power. How to fit o Front surface aspheric Less spherical aberrations means increased add effect Same base and peripheral curve fit (Normal fit) o Back surface aspheric Fit steeper (need edge lift) Higher the e, fit steeper e usually 0.4-0.6 for fit (ellipse)- fit 0.5D steeper e > 1 for kcones and add effect (hyperbola) 3-5D steeper with e = 1, get 2D add Marked Aspheric CLs- SV o Boston Equivalent (B&L)- back surface precut by Boston Biaspheric F2 (low e in BC/high e in periphery- repeatable) o Conforma E-Lens Spherical center with hyperbolic periphery o X-Cel Starlens Spherical center with aspheric periphery Marketed Aspheric CLs- Multifocal o Power from F2 asphericity o Blanchard Essential RGP Multifocal o Boston Multifocal o Lifestyle GP Multifocal o Unilens Marked Aspheric Soft CL o Single vision CV Frequency 55 Aspheric o Multifocal Ciba Vision Focus Progressive Aspheric center add (~2mm) Unilens 38 Front aspheric with near center Rules o 0.1mm steeper = low mod flattening (e) o 0.2-0.3mm steeper = mod high flattening o can only fit with aspheric trials (Large BC increments- 0.1mm) o consultation helpful. Follow fitting guide and learn from experience. Use only 1-2. o Front surface Center near o Back surface Center distance e values > 1.0 (hyperbolic) Low add powers Centration helpful o Multifocals May be considered simultaneous (majority) and translating design. Presbyopia CL will work if patient is: o Dependent on Srx o Motivated o Following instructions o Possess discretionary funds o Decreased corneal and lid sensitivity, due to lid lax o May have long history of CL wear. Wont work if o Decreased tear voume/quality due to hormones, meds, etc. o More medications that might dry eye o Fear of CL, anything touching eye if never worn before o Decrased importance of cosmesis o Medication interactions o Decreased pupil size. o Make sure that you establish realistic expectations Options o Distance CL with near overcorrection, like OTC readers Example 1 Patient Age 47- requires +1.50D add. SRv OD: -4.25 -0.50 x170 OS: -4.50DS CL Rx OD: -3.75 OS: -3.75 OR OD: +0.25 -0.50 x170 OS: plano DS FP OU: AA/DS/Avg/C o Prescribe near overcorrection +1.75 -0.50 x170 +1.50DS Specify near PD Specify on SRx for near use over the CL. Example 2 Patient age 42 requires +1.00D add SRv OD: +2.00 DS OS: +1.50DS CLRx (D) OD: +2.75 OS: +2.25 OR (D) OD: plano DS OS: +0.25 -0.50 x090 CLRx (N) OD: +3.75 OS: +3.25 OR (N) OD: -1.00 DS OS: -0.75 -0.50 x090 FP OU: AA/DS/Avg/C o Prescribe distance spectacle prescription of: OD: -1.00DS OS: -0.75 -0.50 x090 o Near CL with distance overcorrection. Good for those with a lot of nearwork. Resembles young myopes. o Monovision One eye is fit for distance, the other eye is fit for near. Simultaneous (distance and near) #1 presbyopic Cl option Only option for those with LASIK Success rate o 80-90% (most successful fitting modality) Adaptation rate o 15 min- 1 week depending on the patient. Average about 3 days. Advantages Can use same fitting philosophies and lens materials. Can use same lens replacement schedule Less expensive than BF Don’t fit Patients who do mostly near or mostly distance work Patients with reduced VA in one eye (amblyopes) Fitting Selection of near eye o Dominant eye for distance (most prevalent philosophy) if most distance tasks are utilized. o Vice versa if the dominant eye for near if do mostly near work. o Near lens for placement of vocational (typing) or avocational (car mirror) needs o If one eye has good unaided distance vision, fit other eye for near. o If one eye has good unaided near vision, fit other eye for distance. o For RGPs, fit both eyes because there needs to be the same sensation. Near Stereoacuity Stereo is only needed with very detailed near work. No monovision. Koetting (1970) found 94% of monovision patients had normal stereopsis when age matched. Christie and Sarver (1971) found little or no loss of stereopsis with adds of <1.00D. Blake, et al (1980) reported that a “suppressed” eye may contribute to stereopsis. McGill and Erickson (1988) reported reduction in stereoacuity with monovision. This is a function of the add. Increased add means decreased stereo. Distance Stereoacuity Back (1987) found that monovision wearers exhibited a significant loss in distance steresoacuity when compares to soft bifocal CL wearers. Rouse et al (1988) found that static stereo deficient subjects can use dynamically changing disparities to make depth judgements. Binocularity Loshin, Loshin, and Comer (1982) found that for adds up to +1.50, binocular summation in contrast sensitivity function was lost for middle frequency and high frequency (fine detail). It was retained for low frequency. But, all binocular summation was lost with adds greater than +2.00D. Peripheral Vision McLendon et al (1968) tested VFs using a 3mm target. They found that there was a decrease in the VF of 0.2 degrees for the eye corrected for near as compared to the field of the eye corrected for distance. But, there was an iveral increase of ~5 degrees for CL correction as compared to spectacle correction. o With monovision, 2-5 degrees are lost Lit, Stern, and Edrington (1991) found that adds <2.00D had little or no effect on the binocular view. Subjects demonstrated ~ a 2-5 degree field compression with adds >2.00D o Note that motion detection in the peripheral retina is least affected by blur. Legal Concerns Harris and Classe (1988) o Altermatives need to be explained o Limitations should be presented o Have patient sign an informed consent o Need to instruct the patient of adaptation. o Caution against driving or operating heavy machinery during adaptation to monovision. Nakagawa (2000) o National Transportation Safety Board (NTSB) determined that the probable cause of Delta aircrash on 10-19-1996 was due to inability of pilot to overcome misperception of airplane’s position relative to the runway due to monovision. Slutsky, Wang, Edrington (2000) o Pilot’s landing ability not related to distance stereo. o Bifocal CL Alternating Analogous to SRx bifocals. 2 segs with 2 powers. Lens has a small segment (3mm) and needs to translate. With large pupils, one can have simultaneous vision. Simultaneous See distance and near at the same time (analogous to progressives). Can also get an intermediate. Produces ghost images and brain chooses which to see. Decreased VA a little. RGP Concentric or Annular BF CL o Can use regular fitting philosophy assuming that the lens centers well. Can fit up to 6D steeper. o Central zone should be smaller than pupil. Usually 3mm or less. Some are larger if utilizing both designs. o Usually fit as a simultaneous design. Can be fit as an alternating design. o If designed as an alternating bifocal Need more movement (translation) Need larger central zone so there is no simultaneous vision. o Concentric or Annular Segment Good Not dependent on translation Bad ~50% light available at each viewing distance, reducing VA Sxs of glare, haze, haloes, ghost images because we see 2 images at once. Dependent on pupil size. Monovision: fit one with centrad, other with reverse centrad. If you use the same, the VA is usually not as good. Aspheric MF CL o F1 or F2 can be aspheric. Majority are F2. Made via blending various radii of curvatures. There is an add effect by adjusting the tear lens. o High eccentricity = high add. There is a gradual increase in plus towards the edge. This gives an intermediate vision as well. o Simultaneous or Alternating? Dependent on eccentricity of lens Pupil size dependent o Usually fit steep centrally: can be lid-attached (i.e. Hi-Rider). This is to center the lens and get an add effect. o Lens analysis BC- tilt radiuscope Looks like warp if youre not on the center No distinct zones are seen. CLP- Schiener’s disc Pinhole it or use a smaller aperture. Shift sideways to read add. Eccentricity Add Effect 0 (circle) None 0.1-0.9 (ellipse) Small (+1.00) 1.0 (parabola) Medium (+2.00) >1.0 (hyperbola) Large (+3.00) Note that the add effect is not the same on every patient due to the varying e values. o Good Not as dependent on translation Intermediate vision, more like “natural” vision. Early presbyopes o Bad Add effect often not sufficient (decreased VA at near) Limited add capabilities based on parabolic/hyperbolic manufacturing. Spectacle blur due to edema. Add dependent upon pupil size Critical near vision needs, “swim” Fused Crescent BF o These all contain a seg. o Fused crescent Add has higher n o Prism ballasted Usually 1-3D Add 0.10mm to ct for each 1pd. Selectively thin area you desire to position under upper temporal portion of the eyelid (watermelon seed effect) Truncation may help stabilization rotation. It also drops the lens. o o o o o o SCL Lower limbus should be tangent to lower lid (+/-0.1mm) Segment Lens must catch on lower lid in downgaze Alternating Design In theorey Does BF drop fast enough so patient can see distance quickly? Don’t want to see both at the same time. Lens Analysis BC- radiuscope, should be spherical (watch out for warp) CLP- use small aperture lensometer or blacken area of lens not being measured with a visavis marker. Prism- use lensimeter. Needs to be in a BD position Seg Height- use 7x. if truncated, be sure to measure for the “ideal” bottom. More ideal if rotated due to convergence. Advantage Crisp VA at both distance and near Disadvantage Unable to meet vocation or avocational needs for upgaze Cant do adds on top (no double D) Not good for those with flaccid lids. Don’t fit With monovision patients Those with a lot of near tasks Loose lower lids. Translating Alternating Image Designs o None in SCL design Simultaneous Image Designs o Concentric or annular segments Acuvue BF Concentric design on 5 alternating zones of distance and near. Pupil smart, because size independent 1 BC SRv EDS- adds in 0.50D steps Loose lens OR +/- 0.25D. Do not use the phoropter. It creates a false environment Adjust D/N Rx as appropriate. o Aspheric B&L 2BC Comes in high and low adds Ciba Progressives Also daily disposable 1BC ½ Add + SRv EDS loose lens alright. Efficient, comfort, handling Cooper Frequency 55 MF 1BC SRv EDS D lens: dominant in center N lens: non-dominant in center Centrad/reverse philosophy In 3 adds: +1.50, +2.00, +2.50. o Diffractive i.e. Diffrax or Hydron Eschelon. Uses prism to create 2 images Used more in Europe Who should I fit? o Patients with Motivation Realistic expectations “Spherical” SRs Adaptation is pretty bad for toric bifocals Hyperopia greater than 1.00D Myopia greater then 2.00D. o Modified/ Enhanced Monovision Modified- 1 SV CL and 1 Bifocal Enhanced- can overlap Rxs. Distance/intermediate and Intermediate/Near. o All options are available with either RGPs or SCL The problem with the SCL and translating designs is that it is not available because it is too large to translate. Clinical Myopia Control Methods of Treating Myopia Spectacles CL o SCL o RGP Surgery Myopia Control Bifocals Pharmaceutical Agents (Atropine) CL (RGPs) o The Possible Influence of CL on Myopia (Stone)- 1976 London Refracting Hospital, n = 150 (120 after 4 years) 80 patients in CL (8.5-16.5yo) increased -0.50D 40 patients in SRx (6.5-16yo) increased -1.75D o Refractive Stability of CL Wearers (Brungardt and Brungardt)- 1980 13-30yo; 12-42mo. 74% no change while wearing CLs. When cornea flattens other components change inversely so that refractive error usually remains unchanged. They infer that a like sample of SR patients would show no change. o Attempts to Reduce the Rate of Increase of Myopia in Young People (Goss)- 1982 Criticism CLs used at older age = myopia stabilization CLs tend to over correct the required minus power so that myopia could increase before a measured drop in VA with lenses Corneal flattening induced by CLs decreased refractive D of the eye. None of the many different theories have been shown to be consistently effective in reducing the rate of increasing myopia. o Variation of Refractive Error During the First Year of CL Wear (Hovding)- 1983 SCL wearers demonstrated an increase in myopia o Is Myopia to be Controlled by Wearing CL? (Kemmetmuller)- 1987 Law of functional adaptation 20,673 CLs 72.05% no change in refractive error. 25,639 SRs 24.01% no change in refractive error. o The Role of Bifocal and CL in Myopia Control (Grosvenor and Goss)1988 Silicone Acrylate Lenses on 9-13yo after one year 58 CL increased in myopia by -0.06D 10 part time wearers increased by -0.60D 24 controls increased by -0.43D o Use of Silicone Acrylate CL for the Control of Myopia: Results after 2 years of Lens Wear (Grosvenor, Perrigin, Perrigin, and Quintero)- 1989 After 2 years of CL wear o o o o o o o o 100 children (8-13yo), after 2 years, n = 60. 58 full time increase in myopia -0.28 +/-0.60D 7 part time increase in myopia -0.93 +/-0.54D 31 SR increase in myopia -0.80+/-0.77D Only half of the mean stabilization of myopia is due to corneal flattening. Silicone Acrylate CL for myopia Control: 3-Year Results (Perrigin, et al.)- 1990 n = 56 CLs Increase in myopia 0.48 +/- 0.70D SR increase in myopia 1.53 +/- 0.81D Corneal flattening accounts for < ½ of power change Long Term effects of hydrophilic CL on myopia (Andres)- 1990 SCLs have no affect on myopia progression although other reports describe phenomenon of “myopic creep.” This is not validated. Use of CL in Progressive Myopia (Shapiro, Kivaev, Kazakevich) n = 535 385 RGP wearers no change in 73.4% 150 SR wearers no change in 10.8% RGP CL for Myopia Control: Effects of Discontinuation of Lens Wear (Perrigin, Perrigin, Quintero)- 1991 Effect of RGPs on myopia progression is diminished if lens wear is discontinued, however it is still less than if SR only was worn. Do RGP Lenses Control Myopia Progression? (Grosvenor)- 1991 Is a diffence of 1.00D worth it? A 3-year Study on the Effect of RGPP CL on Myopic Children (Khoo, Chong, Rajan)- 1999 There was a decrease in the progress of myopia in children wearing the lenses compared to children wearing spectacles. For effectiveness, lenses needed to be worn about 8 hours a day. n = 105 (10-12yo with >1D myopia and <3D cyl) RGP: 1.26D decrease in myopia, K flattened 0.45D, axial lengthened 0.66mm. SR: 2.34D increase in myopia, K flattened 0.21D, axial lengthened 0.93mm. Correction of Myopia Evaluation Trial (COMET) (Gwiazda, et al)- 2003 A randomized clinical trial of PALs vs. SV on the progression of myopia in children Use of PALs slowed the progression of myopia by a small amount during the first year of study compared to the SV group. Increase of myopia of -1.28 +/- 0.06D in the PAL groupand -1.48D +/- 0.06D in the SV group. The 3 year progression difference was 0.20 +/- 0.08D between the 2 groups. CL and Myopia Progression Study (CLAMP) (Walline) No current published data Large dropout rate; 80% success (8-11yo) o Prenzipine Study (PIR) (FDA) This is studying pharmaceutical intervention. Pirenzipine is put out by Novartis as an ulcer medication. It is a H1 selective muscarinic antagonist, causing decreased accommodation and no dilation. Glaucoma medications and enzymes are also being studied. They think that glaucoma medications would decrease IOP, and would decrease axial elongation. Enzymes tighten and prevent tissue expansion. o Singapore and Taiwan Myopia Progression Study (Leung and Brown)1999 Progression of myopia in Hong Kong Chinese schoolchildren is slowed by wearing PALs. Mean increase in myopia, over 2 years, for SV group (n=32) was 1.23D, those wearing +1.50 add (n=22) was -0.76D, those wearing a +2.00 add (n=14) was -0.66D. o Conclusions Only Baldwin’s paper says that there is no change. Walline- 2001 Commented on all studies No control group in any and subject loss Only 2 studies looked at axial length (Baldwin and Khoo) What about dropouts? What about age (>16yo)- CL were utilized at any age where myopia stabilizes. CL overcorrect minus power, therefore myopia could increase before a measured drop in VA with lenses. Increase in myopia late in life usually due to change in axial length, not the cornea. Studies with bifocals not as strong as CL. Orthokeratology What is is? o This is a programmed replacement of lenses/ part time wear to reshape the cornea with the intention of decreasing refractive error. o This drops the e value back to 0, creating an oblate cornea o Squeezes the epithelium centrally with peripheral swelling. Background o Early Chinese applied small bags of sand on eyelids overnight changes of the cornea occur with CL wear. o Bates Method- Palming o Causative Factors Lens-cornea bearing relationships Lens diameter Center thickness Mass Position (***)- most causative Duration of wear Lid tension Role of blink o Other Considerations (little predictive values) Tensile strength of the cornea Ocular rigidity IOP A very low IOP does not hold the shape of the cornea. An increased IOP means a decreased success with OK) Individual tissue response. o Jessen was the first to do OK with the suggestion that the BC should be changed so that the LL compensated in power for the refractive error. This is basically the premise of the Ortho Focus technique. Research o Bottom Line Variability; corneal flattening didn’t agree with BC flatness. The flatter the fit, the greater the variability. Position of the lens is important (centration) Induced WTR astigmatism OK is an individualized process. It is best done at night o Fitting Philosophies (All are successful to some degree) Jessen Method (62) Plo lens, tear lens corrects myopia i.e. a 1D myope would be fit 1D flat. Tabb Method Slight ACT fit with an aspheric periphery. Some flattening is still obtained. Gates Method (71) 1.50 flat Nolan Method (72) 1-1.50 steep Fontana Method (72) Central bearing of 6.0mm, one piece lathe cut bifocal. 1.00D flatter in the paracentral zone. Freeman Method (74) 0.50-1.00 flat Zift Method (76) On K- 1.00D flat Shed Method Tangent touch on the flattest K (usually 0.50 flat) May-Grant Method (MGM) (77) 0.50D progressively flatter until +0.50 CLP conventional tricurve RGP with BC fit slightly flat (0.501.00D AT) Jenkin Method Slightly steep fit Paige Method (81) Plus Lens Increment (PLI) fit BC such that CLP will be +0.75D. Harris-Stoyan Method (92) 1.00-1.50D flat, SCr is steeper than BC Mountford Method (97) Driem Method (97) Wave-theorey Method o Modern OK Corneal Refractive Therapy (CRT) (00) Similar to Jessen method, use of sigmoid reverse curve and landing zone to maximize effect. This was the first approved overnight use. Terminology o Reverse Zone Depth (RZD) Depth of the secondary curve Affects sagittal height 550 microns (steep) to 450 microns (shallow) means that there is a decreased sag, meaning that it is flatter. If the RZD is too deep and lifts the treatment zone, it is called bridging. o Loading Zone Angle (LZA) Alignment curve Want even alignment. Toe down- too close Heel down- can lift lens Tangent- ideal. Paragon CRT (01) Reverse Geometry Flat BC Steep secondary curve Indicated to improve lens centration Use when calculated secondary curve is steeper than the BC Good fit minimizes areas of excessive bearing or pooling. Seen in both RGPs and SCLs (B&L SL66/ FlexLens) First generation- Accelerated o Topographical changes Next generation- Advanced- dual tear reservoir, compensated aspheric dual surface o For OK and post-sx. Orthofocus BC fit flat enough so that the TL compensates the power of the refractive error. Corneoplasty This is used in conjunction with OK. Vitrease (Hyaluronic acid), an enzyme, is injected into the stroma with reversing drops so that the shape is held. It has a proposed longer duration of the OK effect during the retainer phase. Terminology o BC o Secondary Curve; reverse curve, reverse zone depth o Third Curve; alignment curve, return zone, landing zone o Fourth Curve; edge lift Fitting o Patient selection Motivation (min VA requirement vs. “tired of glasses”) Patients expectations- realistic? Time frame: ~30 days to hold/maintain stability. o Patient Education Time commitment- maybe >1 CL to mold K. A lot of chair time. RTC: 1 day, 1 week, 2 weeks, 1, 2, 6, 9 mo, 1 year. Financial Commitment- expensive. No guarantees, no refunds. OK is very difficult to predict. o Preliminary Testing Thorough case history to include information discussed above. Establish baseline Unaided VA Corneal measurements (keratometry and topography) Refraction (objective and subjective) o Diagnostic CL Fitting CRT Take flat Ks, flatten by magnitude of refractive error and add extra 0.50D fudge factor so that the CL does not pinch the K. o i.e. Ks 45.00 @ 180, 46.00 @ 090. Rx = -3.50. Flat = 45.00 7.50 -3.50 x 0.2 = 0.70. Add to flat K. 7.5 + 0.7 = 8.20. Add +0.1 for correction = 8.30. For emmetropia, all corrected for +0.50 sph Tables available. o Flat K mm o Rx sphere mm o Add 1 and 2 o Add 1mm. Conventional Lens Design (Tricurve) A lens that is progressively flatter. The SCr is flatter than the BC Determine optimum fit (AA, MBA) Order BC 0.50-1.00 flatter than optimum fit Use mid to high Dk lens material Greater center thickness to facilitate OK effect. Possibility that this induces cyl? Accelerated Lens Design (Reverse Geometry) Multiple curves. OZ 6-7mm, SCr = 2nd OZ. Decreased centration, increased K distortion, steeper secondary curves, fit 2D flatter than flat K, steepend secondary curve to fit flatter (and increase OAD) Secondary curve is ~3D steeper than BC Diagnostic fitting is imperative o Select lens that is 1.50-2.00D flatter than flat K o Appropriate lens fit will have central bearing area of 4-5mm, mid-peripheral pooling (2-3mm wide band) and lens movement of 1-2mm. o Lens centration is important. This method is faster than standard OK. o 1-3mo (vs. Standard: 9-16mo) Advanced Lens Design (4 Zone Lenses) This changes the cornea from prolate to oblate. Secondary curve is steeper than BC or use of sigmoid curve (2-12D steep) Integration of topography and computerized calculations o Lens BC similar to Jessen method of BC selection o SC determined based on eccentricity measurements and/or HVID o Fit looks similar to Accelerated design, centration is important. Fudges to give a hyperopic shift to increase time without SRx. Dual Tear Resevoir Use angles and curves to create an elevation. For advanced myopia. o Changing Lenses Normally use 1 Changing 0.1mm is equivalent to a flattening of 0.5D. Secondary curve shallow makes fit shallow and drops it closer to K by 21 microns. o o o o o Changing BC alters only by 7 microns Chaning LZA changes it by 12 microns. Dispensing and Follow-up Dispensing is no different than any other RGP lens. Wear schedule Gradual increase in wear time if no previous lens wear The longer the wear time, the greater the effect o Overnight The risks are the same as any RGP overnight wear. o Day wear Test at Follow-up Aided VA OR (Should be plano to +0.50) Fit assessment Unaided VA Corneal measurement (keratometry, topography) Refraction (objective and subjective) Corneal health assessment As refractive changes occur lens changes are necessary Old: change 0.25-0.50 flatter CRT: modify RZD/ LZA Retainer Lens Wear Now, basically wear the same lens throughout, or the last lens fit. Retainer lens selection Retainer lens wear schedule. Comfort level of doctor and patient. Modern OrthoK Aka PCM (Precision Corneal Molding), CKR (Controlled KeratoReformation), or CRT (Corneal Refractive Theraphy). Accelerated OK Reverse geometry lenses Topographical changes Advanced OK Dual tear reservoir reverse geometry lenses Overnight applications Driemlens Terminology Base curve Secondary curve; reverswe curve, reverse zone depth Third curve; alignment cuyrve, return zone, landing zone Fourth curve; edge lift Corneoplasty Intrastromal injection of an enzyme orthoK lens wear proposed longer duration of orthok effect during retainer phase (3 mo). o Benefits of Topography Selects good candidates. No irregular Ks. Follows change with time. Central islands Bridging with poor fitting OK RGPs Steep fitting response. Causes: Large OAD, too deep RZD, landing zone too high Smiley Face Flat fitting response Inferior paracentral arcuate distortion (IPAD) Decenters. Due to: decreased OAD, RZD too shallow, LZA too flat. Bull’s Eye: Ideal Centered concentric area of flattening Ring of midperipheral pooling Want uniform corneal power over visual axis Need 10 microns TL between CL and K Keratoconus Definition o Keratoconus is a progressive, noninflammatory ectasia (bulging) resulting in thinning, protrusion, and distortion of the central cornea. It occurs a little inferior, but can be located anywhere. o Results in irregular astigmatism o Bilateral and asymmetric Average 4D 1.5-2 line difference (3D in Rx) o women = men Patient Education o Not going blind o No LASIK o Don’t rub eyes o Have a family Diagnostic Signs o Fleischer’s Ring o Vogt’s Straie o Corneal scarring o Shows up well with DFE. Look at the red reflex. o See bulging with optic section of SLE. Onset/Course o At puberty or later Stabilizes in 3rd/4th decade? o The average self-reported age of diagnosis in the CLEK Survey (n=1579) was 27.3 +/- 9.5 years o Theory that the younger the age of onset, the more progressed the disease becomes. o Penetrating keratoplasty is indicated when the patient can no longer tolerate contact lenses or the BCVA is reduced (generally due to corneal scarring). Even with success, there can be a period of time before the final VA is achieved. More than half still require CL to overcome residual astigmatism or myopia. o 5% of patients (73 eyes of 63 patients) who enrolled in the CLEK study with no corneal transplant have undergone PK in one or both eyes in 4 years. o The severity of the condition and the treatment method depends on how steep the cornea is, the visual performance, the duration of the disease, the condition of the fellow eye, and how bad the clinical signs in an eye are at presentation. Incidence and Prevalence o Average annual incidence of 2:100,000 (Kennedy, et al.) o Prevalence rate of 54.5:100,000 (Kennedy et al.) o Prevalence rate of 370:100,000 (Hofstetter) o 56% male in CLEK study (n=1209 kcone patients) Etiology o Hereditary 13.5% of CLEK patients had a family history of kcone suspect AD inheritance pattern with variable penetrance of the gene. o Endocrine o Collagen Increase in stromal intercellular substance and a decrease in total collagen, accompanied by an increase of structural glycoprotein component. o Eye Rubbing 48% of CLEK patients reported rubbing both eyes vigorously and 2% reported rubbing only one eye vigorously. (3.2% unsure) could this possibly release an enzyme in the stroma causing thinning? The kcone corneas have decreased levels of enzyme inhibitors and increased enzyme activities that can degrade the various extracellular matrices within the corneas. This imbalance results in stromal thinning and Bowman’s membrane breaks seen in kcone corneas. o Apoptosis It is caused by chronic epithelial cell damage from eye rubbing and CL wear, increased levels of LAR and decreased levels of TIMP-I. o Oxidative damage Within the kcone corneas, there is an accumulation of reactive oxygen species that results in deposits of cytotoxic byproducts (MDA and peroxynitrates) that can damage the corneal tissues. The cells that are only partially damaged by oxidative stress undergo the process of wound healing. This increase in wound healing causes local areas of fibrosis and scarring close to the Bowman’s layer of the cornea. o Previous rigid CL wear Associated Diseases o Atopic disease, such as hay fever, allergy, asthma, or eczema 52.9% of the CLEK patients had hay fever or allergies, 14.9% had asthma, and 8.4% had atopic dermatitis. 10-20% of the general population of atopic disease o No patients at baseline in the CLEK study reported a history of Down Syndrome, Marfan Syndrome, focal dermal hypoplasia, Ehlers-Danlos syndrome, infantile tapetoretinal degeneration, oculodentodigital syndrome, osteogenesis imperfecta, or Rieger’s anomaly Symptoms o Decreased vision and/or visual distortion at distance and near o Monocular diplopia (or multiple images or ghosting of images) o Frequent spectacle changes without much improvement Signs o Retinoscopy Irregular reflex with accompanying scissors motion o Manifest Refraction High amount of astigmatism Often oblique astigmatism (or ATR) Often high myopia (although many are hyperopic) Poor endpoints and repeatability 58% of eyes in the CLEK study had >20/40 VA through manifest refraction. 88% had 20/40 or better with CLs. Average is about 20/25. Fudge more towards the minus. Patient ed that the rx can fluctuate. o Keratometry Steepening Axes not 90 degrees apart With >46D or large change, do topography. Distortion Does not clear with blinks More pathognomonic than steep Ks. Mean flat K was 49.49 +/- 6.01D in the CLEK study 18.3% of CLEK patients had K readings flatter than 45.00D o Biomicroscopy Thinning and protrusion of the cornea, usually inferior/central Up to 1/5th of normal corneal thickness. Thickening of the corneal nerves. Hydrops due to descemet’s membrane rupturing and aqueous flowing into the cornea. Reduced IOP? (False low) Vogt’s Straie Usually vertical, fine, white lines fanning around the base of the cornea. They are subepithelial fibrillary lines resulting from the outward bowing and thinning of the ecstatic cornea. Disappear with pressing on the eye. 65% of CLEK patients had striae in one or both eyes. Fleischer’s ring (full or partial) Formed from hemosiderin (iron) pigment deposited deep in the epithelium. As the ectasia progresses, the ring tends to become more densely pigmented, narrower, and may become complete. Broken down circle at base of cone. Seen better with DFE. 86% of CLEK patients had this ring in one or both eyes. Scarring- from condition (wound healing or eye rubbing) or poor fitting CLs 53% of CLEK had scarring in one or both eyes. Munson’s Sign Not diagnostic (only seen if very bad) Look down and lower lid distends. Instrumentation o SLE Detect corneal signs. o Handheld keratoscopes (Placido’s disks) Early kcone is characterized by a downward displacement of the horizontal axis of the Placido disk. o Computer-assisted videokeratoscopes The most sensitive device for confirming the diagnosis of keratoconus. This device generates color-coded maps and topographic indices. Keratoconus appears as an area of increased surface power surrounded by concentric zones of decreasing surface power. o Pachymetry This instrument can be used to help confirm the diagnosis of keratoconus but it cannot be used as the only method to make the diagnosis because of the large range and variation of pachymetry readings both centrally and paracentrally in the normal population. o Keratometer DDx o Keratoglobus, Pellucid Marginal Degeneration, Terrien’s Marginal Degeneration, Marginal Furrow Degeneration Management o Fit to enhance or improve vision, not to slow progression of keratoconus. o Eventually RGPs are the best. Transplants are the last resort. Contact Lens Options o The use of contacts “Ideal” RGP Keratoconus Fit o Sagittal height of BC to equal or slightly exceed the sagittal height of the cornea for the same chord diameter (not too steep/flat) o No excessive areas of tear/debris pooling underneath OZ o Good exchange of tears o Average PC. Keratometry o Readings are difficult, yet these are better than topography. o Extend range by utilizing a +1.25D spectacle trial lens and adding 9D to the drum reading. Add this on the patient’s side. Can also add +2.25. o Use steep K only as a starting point for selection of diagnostic CL. o Axes not necessarily 90 degrees apart. Fit by FP o Goal is slightest amount of apical clearance or feather “three-point” touch. This is the steepest flat fot. In general, get a slight AT. Always bearing on a slight raised area. o Goal is to minimize areas of mid-peripheral tear pooling and around base. Treat by decreasing the OZ Can lead to dimple veiling. o Goal is to obtain average PC Err on side of too much (max>min) Research o Korb, Finnemore, and Herman (82) n=7 One eye fit AT, the other AC x 1yr. Results: 4/7 flat developed scarring 0/7 steep had scarring. Problem: its an asymmetric disease, so cant compare, too many variables, n =7. o CLEK 12% fit AC 88% fit AT <45D 1.18D flat 45-52D 2.38 flat >52D 4.01 flat Average 2.86 flat, sd = 3.31 Conclusion: scarring is due to degree of flat fit. Lens Parameters o BC radius is determined by FP analysis o CLP is determined by overrefracting endpoint diagnostic CL and adding OR-EDS to power of diagnostic lens. o OAD is generally smaller than for cosmetic orders, for example, 8.6mm. o OZD is usually smaller, i.e. 5.5-7.0mm. Smaller OZ sizes used with steeper BCs. o SCr is flat relative to generally steep BCs. SCR should generally be ordered in the range of 8.00-8.50mm. o TCr/w is standard, i.e. 11.00mm/0.2mm. o ct is generally in the range of 0.10-0.13mm due to the high minus CLP encountered. For lesser minus orders, thickness should be increased due to the extra removal of edge material necessitated by the flatter SCr. o Material should be RGP. Currently we recommend FluoroPerm 30. Avoid lenses with UV inhibitors due to decreased ability to interpret FPs. o Blend (medium) junction between BC and SCr with a radius tool approximately half way between the BC and SCr. o Ex BC 6.50mm (51.92D) CLP -9.50D Heavy minus. No correlation between the CLP and SRx. Increased + TL. OAD 8.6 Smaller better OZ 6.5 Decreased for increased centration. To decrease flare/glare, go to 5.5. SCr 8.5 0.7 flatter than BC is way too tight. Judge with FP. TCr/w 11.0/0.2 standard Ct 0.14 Flexure not a concern. Fudge Thicker. Blend Medium need a good blend. Material Dk30 decreased Dk to help Modification. Specify no UV. Trouble-shooting o Decreased Wearing Time Problem Cause: Binding of peripheral curve system leading to decreased tear pumping Recommended Treatment “open up” PC system, i.e. flatten SCr or further blend. Note: laboratories oftentimes “correct” your order, therefore secondary curves you receive for your Kcones can be steeper than ordered. o Stippling Staining around the base of the cone Probable Cause: excessive midperipheral pooling of metabolic debris. Recommended treatment Decrease OZD o Coalesced, Abrasive Staining at Apex of Cone Probable cause: mechanical Recommended treatment: if AT, order steeper BC. Helpful Hints o Avoid toric designs unless peripheral fitting relationship indicates need. o Correct residual (oblique) cylinder with a spectacle overcorrection. o For 3-9 Staining Treat with copius lubricants Piggyback with disposable (-0.50 AV/ Ciba N&D) The night and days are more expensive and rip easier with RGPs. This is only a temporary solution. Worry only of the condition worsens or coalesces www.nkcf.org Pellucid Use SCL if VAs are still good (early) With RGPs, fit superior cornea (large OAD) o Will have a lot of AT (happy medium) o Inferior bulge, so the CL will ride low. Management o Soft Toric Too thick inferiorly- neo concerns o SoftPerm Good vision, good comfort, good centration, but poor physiology: center has a Dk of 13 and carrier has a Dk of 5. The center can also rub and irritate the cornea. o RGPs K-conus design- lens may position inferiorly Lid attachment- inferior edge lift may pop lens out Large OAD- good idea Covers the visual axis Good centration Good stability Dyna Intralimbal by Lens Dynamic o 11.2 OAD, 9.4 OZD, steep, standard, or flat PC system. No BC is indicated. o 3-9 staining problems o this is now available in reverse geometry design (2D, 3D, and 4D steeper than BC) o custom always possible Other large lenses o Jupiter (Innovations in Sight)- 15mm o Macrolens Einstein (C&H)- 15mm Fitting the Post-surgical Cornea Post-surgical indications o Penetrating Keratoplasty Graft Considerations Steep grafts Flat Grafts Tilted Grafts o Same as irregular cornea o Large OAD Proud o Sphere o Aspheric o Fit-like keratoconus Sunken/Plateau o Graft and host same size o Reverse geometry Eccentric o Same as irregular cornea o Large OAD High Cylinder o If irregular, fit sphere o If cyl is corneal and no corneal distortion is present, RX bitoric. Main considerations The size of the graft o Keep OAD within limits of the graft The tilt of the graft o Lens decentration and stability Lens Stability o Increase OAD (>12mm) Staining of grafted tissue o Careful observation/ unacceptable o Chronic staining into the cornea may be an early sign of graft rejections. Refer back to the corneal specialist. 1-3 mo post-op is highest risk. Watch for: pain, redness, blur, and increased light sensitivity. Sutures o Running, interrupted, or combination. o This is a preference of the surgeon o Watch for broken sutures. CL Fitting Up to 50% of post-PK patients will benefit from CL wear. Over 50% of post-PK patients have 4 or more D of astigmatism. Irregular astigmatism is common Fit 4-6mo post-sx. May RX soft if irregular astigmatism is minimal. Prefer silicone hydrogels, avoid toric SCL. o Post cataract surgery Aphakic lenses (RGP) Small centering lenses Large lid attachment lenses BC = avg to steep K for centration OZ depends on pupil size/shape. Because these can be very thick, there needs to be an increased Dk. IOL still the best route. Problems with RGPS o Ejection, because small and heavy o Displacement o Temporal ride. Falls down and out. Aphakic Lenses (SCL) Fit conventionally Medium water DW, high water EW Problems with SCL o Ejection o Displacement (<RGP) o Visual performance not optimized. No aphakic toric SCL available. o Post trauma RGPS DxCL BC = avg K of the good eye. FP analysis Optimally improves corneal distortions SCL Easier to fit Considerations for aphakia Look for vascularization. o With trauma, a vasoproliferative response can be stimulated. Prosthetic lens for cosmesis Piggyback improves cosmesis and enhanced optics. o Refractive surgery Radial Keratotomy Considerations o Number of incisions o Length of incisions, depth o Residual astigmatism o Corneal topography RGPs o Preferred lens choice o Indicated for irregular astigmatism o Topography useful o Pre-surgical data useful o Generally rx reverse geometry sphere Cornea is now oblate. o Sphere Use pre-RK Ks or slight clearance centrally (no bubbles) Align mid-peripherally Relatively steep PC system, but need sufficient edge lift Larger OAD to aid in centration and stability RGP Fitting o Conventional tricurve lens Want central AC Larger OAD and OZ BC align with transition between a flat central zone and steeper midperiphery o Reverse Geometry Lens May improve corneal physiology Conventional/larger OAD and smaller OZ Increases centration and alignment Flatter BC Peripheral curve system steeper than BC Average central values for initial BC Average peripheral values for PC Modify fit by evaluating central and peripheral FPs. o Lenticular Larger OADs Tripod bearing pattern Ideal somewhat feathery SCL o Fewer incisions (<8) o Shorter length of incisions (do not go to the limbus) o Residual astigmatism. MR vision needs to be acceptable and stable. o Silicone hydrogels o Problem with vascularization, especially with torics due to prism. Regular corneal topography. o Watch for “Edge Fluting” If fit on flat cornea, the lens sicks and the edge rides a bit. This is seen with thicker materials. It looks scallop-like. Photorefractive Keratectomy Use axial (useable OZ) and tangential (pt by pt power, not too useful) maps SCL o Conventional o Reverse geometry RGPs o Conventional (AC) o Aspheric o Reverse geometry o Considerations similar to post-PKP Laser Assisted In Situ Keratomileusis Same as post-PRK SCL o Consider reverse geometry RGPs o Sphere first choice o Reverse geometry if indicated. Strategy for reverse geometry lens design for the post-surgical plateau cornea. o Diagnostic Lens Selection- using numerical topography data BC determination Average values over the OZ size o (7.23+7.23+7.21+7.16+6.96+6.95+7.33)/7 = 7.15mm or 47.25D Secondary Curve Average values from OZ to 2-3 mm away o (7.33+8.90+9.14)/3 = 8.46mm or 39.87D. Patient education o “you will not go blind form this condition” blindness equates to complete darkness adequate vision highly possible with specialty lenses o These patients Are usually scared Have had multiple surgeries/procedures Blame themselves for electing surgery Seen may doctors (OMDs and ODs) Have been told that there is nothing else that can be done or that they will go blind. o Do not promise results Therapeutic CL Reasons for Using o Protection of the corneal surface, where the lens serves analgesic, barrier, or structural support roles (“bandage” lens) Relief or reduction of pain associated with corneal epithelial defects or abnormalities. Facilitation and maintenance of corneal epithelial healing. Hydration or dehydration of the cornea Protection of the cornea from mechanical abuses Sealing of small corneal wounds and perforations by splinting the wound and thereby restoring the AC. o Aid in drug delivery to the ocular tissues by serving as a reservoir or soaking the CL in the meds o Improvement of vision for irregular topography. o Prosthesis for ocular disfigurement. Bandage Lenses o General Basic Fitting Principles OAD Usually large to completely cover the corneal epithelium (14.5-16.0mm). this allows less movement. Smaller lenses used when perilimbal bulbar conjunctiva is distorted, redundant, or irregular, such as a scarred fornix. Lens Thickness Usually minimal to promote oxygen delivery Thicker lenses are often used for post-surgical wound leaks as “scaffolding” for healing. This is the bringing of 2 edges of the wound together. It can also smooth the TL with an irregular cornea. Power To minimize thickness, power is usually plano with spectacles worn over the bandage lenses. If power is found to be necessary, consideration should be given to overall lens thickness. Water Content Very controversial area Some believe that high water is better for dry eyes because it acts as a fluid reservoir Others believe that low water is better for dry eyes due to less dehydration effects. Lens Movement Should have less movement than that for cosmetic fits Should not be too tight that they indent the sclera/vessels. Minimization of lens movement is believed to facilitate patient acceptance by decreasing lid sensation. WT DW preferable to avoid complications but sometimes not possible. EW necessary when specified by the particular disease entity. Complications Edema and hypoxia Neo GPC Sterile infiltrates Ulcers Examples Bausch and Lomb o B4 Plano, Plano T, O4 Plano Ciba o CSI Clarity FW CooperVision o Permalens Therapeutic United CL o UCL Bandage Lens these are all more expensive, so most use an off-label lens, such as AV Indications o Traumatic Corneal Abrasions Traditional treatment: CAP Alternative treatment: CAP with NSAIDs o Corneal Epithelial Abnormalities/ Persistent Epithelial Defects RCE Causes o Mechanical trauma o Corneal dystrophies: EBMD, Reis-Buckler, lattice, granular, and macular. Symptoms: pain, photophobia, lacrimation, and blepharospasm Use of a bandage CL o Reason to fit Reduce acute FBS/ pain Dehydration Promote healing/ re-epithelialization o What to fit High water content hydrogel Minimal movement to promote healing EW necessary for 2-3mo. TPAs o Hypertonic drops BID-TID to decrease corneal edema o Hypertonic ung hs if necessary o Broad spectrum antibiotic prophylactically. o Cycloplegic agent o Pain medication o Lubricating drops QID Persistent Epithelial Defects Numerous etiologies: bacterial, viral, fungal, chemical or thermal burns, neuroparalytic keratitis. o Ulcer/epithelial defects that wont heal. Herpes simplex o One of the most common causes of PED o Treated medically for a long period if time before bandage lenses are tried. o Use of a bandage CL Reason to fit Promotion of healing Drug reservoir for antivirlas Decreased discomfort What to fit High water lens worn EW until healing has occurred TPAs Bandage lens with concomitant use of an antiviral agent and corticosteroids. Bandage lenses with decrease the time of healing. Meesman’s Juvenile Dystrophy/ Salzmann’s Nodular Degeneration Reason to fit o Relefi from pain, irritation, photophobia o Improvement of vision What to fit o Low water, thin lens o DW schedule o Regular cosmetic fitting standards Mooren’s Ulcer Reason to fit o Relief from pain o Promote healing What to fit o Low to medium water content lenses TPAs o Corticosteroids in conjunction with lens if necessary Common/ Wet Filamentary Keratitis What is it? Secondary nonspecific diagnosis from primary precipitating clinical conditions which disrupt corneal integrity. Appearance: fine twisted threads of corneal epithelium attach at their base to the surrounding epithelium. Symptoms: FBS and pain, blepharospasm, and epiphora. Treatment goal: remove the filaments o Mechanical removal (1st) o ATs and ung qhs with no preservatives; punctual occlusion. o Use ocular acetylcysteine, a mucolytic agent with decreases the viscosity of mucus, making it easier to peel off. o Use of a bandage CL Reason to fit Mechanical protection Pain reduction Promotion of healing Stabilization of precorneal tear film Not to improve VA What to fit Low to medium water content lenses TPAs Wet condition often requires bandage lens with concomitant use of corticosteroid and atropine. May consider hypertonic gtts if cornea is edematous. ATs and ung Thygesons Superficial Keratitis Unknown etiology: viral etiology suspected Onset: 2nd and 3rd decade Appearance: oval or round grouped punctuate intraepithelial deposits composed of numerous dotlike or stellate opacities filled with filaments (15-20, but up to 50). Symptoms: FBS, burning, and tearing with popping at the surface. Use of a bandage CL o Reason to fit Relief from pain, photophobia, and FBS Promote epithelial healing Improvement of VA SLK o What to fit Low water, thin lens, DW schedule TPAs o Symptomatic relief through bandage lens with concomitant use of low-dose corticosteroids and lubricants. Unkown etiology; frequently associated with hyperthyroidism Chronic inflammation characterized by inflammation of the superior tarsal and superior bulbar conjunctiva More prevalent in females Symptoms: burning, pain, photophobia, blepharospasm, and FBS Use of a bandage CL o Reason to fit Relief from pain, photophobia o What to fit Low water, thin lens, DW schedule Large OAD (16mm) to protect the superior cornea. TPAs o 0.5% silver nitrate usually tried initially, but condition returns. o Pressure patching next to relieve initial discomfort, than bandage lens. o Chronic Edema Fuch’s endothelial dystrophy/ Bullous Keratopathy Most common cause of BK is cataract surgery Symptoms o Severe pain o Loss of vision Use of a bandage CL o Reason to fit Dehydration- draw out edema Pain reduction- protect exposed nerves Promote healing Improve vision Temporary measure while waiting for surgery o What to fit Thick high water content hydrogel Adequate movement Fuch’s may be DW or EW BK almost always EW TPAs o o o o Hypertonic gtts BID-QID Hypertonic ung hs Cycloplegic agent Steroid (to decrease inflammation) and prophylactic antibiotics. o Mechanical Irritations Entropian and trichiasis Reason to fit o Corneal protection o Pain reduction What to fit o Low water content hydrogels o Durable polymers o Frequent replacement program ideal o DW preferable, but EW possible if there are multiple lashes or if the entire lid is turned in TPAs o None necessary but ung hs is beneficial for DW patients. o Possibly epilation o Severe Drying and Erosive Conditions KCS/ Pemphigoid/ Sjogern Syndrome Ocular Pemphigoid o A bilateral, chronically progressive disorder which occurs in about 70% of people who suffer from ciccatricial pemphigoid, a systemic autoimmune disease which produces lesions of the skin and mucous membranes. o More common after age 60 and more common in women. o Ocular involvement is characterized by Progressive shrinkage of the conjunctiva due to the production of fibrous tissue at the level of the conjunctival basement membrane Loss of goblet cells Ciccatrization of lacrimal gland ducts and damage to the meibomian gland orifices. Symblepharon, keratoconjunctivitis sicca, entropian, trichiasis, and eventually keratizition of the conjunctiva and cornea. Ankyloblepharon (fusion of the lid margins) may also occur. o Reason to fit Hydration Protect the cornea Promote healing Pain reduction But, increased risk of CL related complications. o What to fit Thicker, larger diameter hydrogel lenses with low water content Scleral lenses o TPAs Aggressive preservative-free lubricating therapy hourly Anti-staphylococcal therapy for blepharitis may be combined with bandage lenses Immunosuppressive drugs and steroids. Surgical Considerations Post-penetrating/ Lamellar Keratoplasty o Reason to fit Mechanical protection from sutures Wound leaks Promote healing Visual enhancement o What to fit Thicker, medium water content hydrogels for wound leaks For PED, high water content is better RGPs for visual enhancement (irregular astigmatism) o TPAs May be combined with bandage lenses to enhance the therapeutic effect. Post-PRK o Reason to fit Relief from pain Promotion of healing o What to fit Thin, high water content hydrogel Minimal movement o TPAs Voltaren and/or steroids may be combined with lenses at surgeon’s discretion. Post-RK o Reason to fit Improve vision o What to fit RGPs Drug Delivery Hydrogel CLs should improve drug contact time and thereby increase and promote drug penetration into the cornea and anterior segment of the eye. Drug absorption and release were therefore also found to be dependent to a certain extent on the CL parameters. o Depends on water content. High water absorbs more of the drug and releases it faster. Examples o Pilo, CAIs, cystein HCl, acetylcystein, antibiotics, and corticosteroids. Collagen Lenses What are they? o Lenses made of procine or bovine collagen scleral strands. o Available in 12, 24, or 72 hour dissolution rates o Stored in a dry state o Do not contain powder, OAD = 14.5-16mm, BC = 9.0mm, ct = 0.150.19mm, Dk/L = 27; acts like a 63% water content hydrogel o Currently marketed for ocular surface protection following cataract and refractive surgery, PK, and traumatic epithelial defects. o Must be hydrated prior to application with drugs, saline, etc. o Fragile o Costly o Cons: discomfort and reduced VA (20/100-200) due to it dissolving. It dissolves fast and in chunks. Does not melt evenly. How are they applied? o Lenses are presoaked for approximately 5-10 minutes. May be soaked with antibiotics, steroids, or saline. o Anesthetic is applied. o The lens is placed onto the cornea or lower cul-de-sac using forceps. o The patient is asked to close their eyes and gentle pressure is applied. Indications for use o Short term corneal protection o Promote epithelial and stromal healing after surgery o Lubrication o Drug Fitting those with Irregular Topography Topography is the starting point, but must rely on FP analysis. The goal is to minimize areas of excessive clearance (bublles and staining) and harsh bearing. Monitor corneal stainging o Swirl pattern indicates that the lens is rubbing on the K in a circular motion. o Dimple veiling means that there is too much AC o 3-9 staining menas that there is too much edge lift. Goal: small area of bearing with central clearance. Border has feathery transition between touch and clearance. Post-traumatic corneal scar o Commonly associated with corneal lacerations or corfneoscleral lacerations o Topographical changes are dependent of the extent of the injury o Effect on vision is dependent on residual scarring and topographical changes. o Modes of correction Spectacles Not as good (does not correct irregular astigmatism) CL SCL molds to eye, meaning that it is worthless Hybrid- SCL/HCL mix- expensive and breaks. decreased O2 permeability. RGPs are the best. Prosthetic CL Goals o Improve cosmetic appearance of disfigured eyes o Reduce glare and photophobia o Eliminate diplopia o Provide optical correction o Provide occlusion in amblyopia therapy. Cornea o Conditions for which prosthetic lenses can be used Leukoma, microcornea, band keratopathy, and bullous keratopathy. o Artificial iris and/or artificial pupil depending on whether it is a seeing eye or non-seeing eye. Iris o Conditions Heterochromia, aniridia, albinism, diplopia secondary to iridectomy or polycoria, and coloboma Pupil o Amblyopia therapy o Leukocoria secondary to an inoperable cataract o Photoconvulsive epilepsy treatment Color Vision Deficiency Red-green color deficiency X-chrom lens/ Magenta/ Red lens o Soft vs. rigid Ethics Hybrid Contacts Technology 1977- Precision-Cosmet acquires rights to rigid-soft bonding technology 1985- Saturn II is the first commercially marketed hybrid lens. 1989- Sola-Barnes Hind purchases Saturn II technology and introduces new and improved design- the SoftPerm lens. 2001- California-based research group begins developing a high-Dk hybrid lens. The lenses to be developed have a higher Dk, are more durable, easier to fit, and include a full continuum of indications. 2005- SynergEyes receives FDA approval for SynergEyes A and SynergEyes KC. 2006- SynergEyes receives FDA approval for SynergEyes PS and SynergEyes Multifocal. SynergEyes www.synergeyes.com Contact Lens Designs o The RGP is great for optics, and the soft skirt also reduces movement, keeping the lens centered. o Material Paragon HDS 100 GP Center (Dk 100) HydrolEyes Surface Paflufocon D 27% Water Non Ionic Skirt (Group I) Hemiberfilcon Patented Hyperbond Junction o Engineered Design 14.5mm OAD 8.4mm rigid center 7.8mm optic zone Skirt thickness consistent across full power range. o Features and Benefits Gas permeable rigid center for optimal visual acuity. Maintains spherical shape over normal and irregularly-shaped corneas. Precise optics centered over visual axis to correct haloes, sensitivity to light, glare, and blurry vision. Soft skirt material is dimensionally stable and expansion-free for increased stability for consistent, predictable vision. o Trial Lens Marked with a laser o Types i.e. A7992 o A = A lens o 79 = 7.9 BC o 92 = 9.2 skirt SynergEyes A o Patient Candidates Naturally occurring ametropias Moderate to high myopes, hyperopes, and astigmats who desire the pristine vision of an RGP with the all day comfort and stability of a soft lens. o Up to 6D of cyl can be corrected. Any patient who has never achieved good vision with soft/soft toric lenses or who cannot tolerate the comfort of RGPs. Current GP wearers Teens and athletes CL dropouts Irregular Astigmatism Mild keratoconus or mildly oblate corneas. o Trial Kit 20 lenses: 10 BC- 7.1-8.0, 2 skirts each Can be used for multifocal fittings o Available Parameters BC SC Sphere Power 7.10-8.00 in 0.1mm steps 1.0mm, 1.3mm flatter than the BC +8.00 to -8.00 in 0.25D steps +8.50 to +20.00 in 0.50D steps -8.50 to -20.00 in 0.50D steps o Prescribing Empirical Calculator, available on the SynergEyes website Consulting Done via calling the consultation department (877-7332012) with the following information o Patient name or number o Keratometry o Manifest refraction o HVID This measurement can be obtained by utilizing various topographes. If this is not possible, a statistically based default value will be used. o Fitting Philosophy for Normal Corneas Choose the BC Never prescribe flatter than or “on” flat K. Prescribe lenses at least 0.3mm (1.5D) steeper than flat K. Changes in the BC radius will affect the resultant correction power of the lens while on the eye. Therefore, the power of the lens may require proportionate adjustment. Each 0.1mm of BC change requires 0.5D power adjustment. o This should follow the SAM/FAP rule. Ex. 7.6 -3.00 → 7.5 -3.50. Skirt curves 1.0mm flatter are recommended for low eccentricity values. The 1.3mm flatter skirt is recommended for high eccentricity values. HVID changes the sagittal depth on two patients with the same Ks. An increased HVID means an increased sagittal depth, therefore a steeper skirt is required, or a steeper BC. Evaluation of fluorescein High molecular fluorescein is optional for the initial fitting for normal corneas. o It is best to purchase the Fluorescein from Wilson Fluoresoft 0.35% ampules or Flurasafe. Place 1-2 drops high molecular fluorescein in the bowl of lens with saline before application. To apply the lens, have the patient look down into the lens and bring the lens up to contact the cornea. Inform the patient that the fluorescein might sting. Assure the patient that they will not feel that with their final lenses, but it is necessary to evaluate the fit. Allow the excess fluorescein to dissipate and observe the fluorescein pattern after 30 seconds of normal blinking. Subtleties of the fluorescein pattern become more apparent with time. Upon evaluation, there should be some apical vault. o Apical Clearance is the desirable pattern. Apical bearing may result in late-onset tightening. o Insufficient Apical Clearance o Excessive Apical Clearance The use of a Wratten filter may be helpful in viewing fluorescein patterns. Evaluation of movement Look at the edge of the soft skirt where it meets the sclera. There should be no compression of vessels on the sclera, and the lens should move with little pressure from the lower lid with a “push up” test. There should also be no “edge fluting.” Observe centration and movement in primary gaze. The lens should exhibit slight movement (0.25mm) with a normal blink. There should be a slight lag on up-gaze. Let stand for 30-45 min. The hybrid family of lenses has a tendency to tighten with increased wear time. If this lens is not fit steep, adherence is a definite problem that can lead to corneal edema and reduced wear time. Over-refraction Spherical With cyl >2.0D, try enhanced profile or go a little steeper. If there is any unusual residual astigmatism, perform a K reading over the center of the rigid lens. If over-refract is greater than 4.00D, adjust for vertex distance. Troubleshooting Tight fitting lens → Steepen BC Heavy bearing at junction → Steepen SC Insufficient apical clearance o Steepen BC by 0.1mm (Ex. 7.7 → 7.6mm) Excessive apical clearance o Flatten BC by 0.1mm (Ex. 7.6 → 7.7mm) Edge fluting o This is due to the skirt being too flat, so steepen the skirt curve radius Ex. 8.9 → 8.6 If already steep, go to a steeper BC. Scleral Impingment o Switch to flatter skirt curve radius No movement upon blink with insufficient apical clearance o Steepen BC by 0.1mm No movement upon blink with adequate apical clearance o Steepen skirt curve radius Tight lens seal-off o This is observed as a dark heavy touch ring of bearing at junction o Steepen the SCR Ex. Change SCR from 8.5 to 8.2mm o If already in the steep SCR, move to the next steeper BC/SCR combination. o Fitting Philosophy for Irregular Corneas Choose an appropriate SynergEyes lens design based on the corneal shape, not on the patient history or diagnosis. If uncertain of which design is most appropriate, begin with SynergEyes A. Many kertoconic or post-surgical eyes that are mildly prolate or oblate, respectively, can be fit with the SynergEyes A design. Have patients earn the complexity of the advanced designs. Empirical fitting using the SynergEyes A lens calculator or fitting 0.3mm steeper than flat K is NOT RECOMMENDED for irregular corneas. Only rely on fluorescein. The diagnostic set is essential to evaluate proper fit. The use of high molecular weight fluorescein is absolutely necessary. Select the initial diagnostic lens close to steep K. Attempt to vault over the irregular areas. Central clearance (or a “feather touch) is the goal. Touch between the back surface of the lens and front surface of the cornea should be minimized. Fluorescein pooling without bubbles is an acceptable fit. Persistent central bubble → switch to SynergEyes PS. Bubbles and touch → switch to SynergEyes KC PMD With PMD patients, start with SynergEyes A. If apical clearance is not achievable and if the touch is within the central 6mm of the lens, switch to SynergEyes KC. If touch is peripheral and within the RGP center of the lens. Switch to SynergEyes PS. SynergEyes KC o Introduction This is the first hybrid contact lens with FDA clearance, specifically designed for patients with keratoconus, post-LASIK ectasia and high eccentricity. It offers centration, comfort, and stable optics on a range of emerging, moderate, and globus cones. Because it is aspheric, a steeper BC is sometimes required. No orientational positioning in eyes with off-centered bulging/thinning is required. o Patient Candidates Ideal for central or symmetrical keratoconus. The problem comes with highly prolate corneas and touch. o This fluorescein pattern is contraindicated for SynergEyes KC. Emerging to moderate peripheral cones Emerging to advanced central cones Oval, nipple, and globus cones o Trials 24 lenses: 8 BC- 5.70-7.10, 3 skirts each. Powers range from -4.00D to -14.00D sphere power depending on the BC selection. o Available Parameters Diameter BC SC Sphere Power 14.5mm 5.70 to 7.10 in 0.2mm steps Steep, medium, flat Plano to -20.00 in 0.50D steps o Fitting Guide Finding the Cone The radius of the apex of the cone can be determined by moving the cursor in the Corneal Topography program screen directly over the center of the hottest spot on the cornea. If Corneal Topography is unavailable, an estimate of the radius of an inferior cone can be determined by keratometry with the eye in upward gaze. Determine the initial diagnostic lens BC by selecting the closest BC radius in relation to the keratoconus apex radius (Steep K). Ex. Keratoconus apex = 52.50D o Round to next steeper BC = 6.30 (53.50D) In the absence of topography, use steep K to determine the initial diagnostic lens BC. Start with the determined BC in the medium skirt curve option. Follow the fluorescin instillation instructions as directed with the SynergEyes A. When ideal fluorescein pattern is achieved, over-refract to determine the final lens power as instructed in the SynergEyes A section. o Ideal SynergEyes KC Fit Optimum fit will demonstrate apical clearance over the central cornea/ corneal apex, with the steepest BC that is free of central air bubbles with greater than 2mm diameter. Smaller bubbles will typically dissipate. There should be little or no touch in rigid portion of lens. Landing occurs in the soft skirt. Paracentral alignment under soft skirt. Soft skirt free of scleral impingement and “edge fluting” Lens free to move on lid push-up o Additional Fitting Tips The steeper skirt curve radius will add sagittal depth to the lens, and lift the bearing point to produce a lighter landing This improves the comfort and prevents late onset tightening Many corneas with emerging or moderate keratoconus may be fit with the SynergEyes A lens design. SynergEyes KC is required with significant ectasia and high eccentricity. o Troubleshooting If bubbles are present, remove the lens and re-insert with solution in the bowl of the lens. Identify the shape and location of bubbles. If large central bubble is present, flatten the BC radius. If significant touch is observed, note the location of the touch area. If the area of touch is observed at the steepest area of the cornea, steepen the BC radius. SynergEyes PS If significant touch is observed peripherally at the rigid/soft junction, steepen the skirt curve radius. o Introduction First FDA-cleared hybrid contact lens specifically designed with reverse geometry for patients with oblate corneas resulting from refractive surgery, corneal trauma, or degenerative conditions, including penetrating keratoplasty and/or Intacts for keratoconus Offers centration, stability, comfort, and a high degree of visual success, even in most difficult cases. Reverse curve design specifically addresses the altered corneal shape resulting from refractive surgery. This already has an enhanced profile. Design over 3 reverse curve options for customized fitting on a variety of oblate corneas. o Advanced Lens Design Oblate posterior surface 6.5mm spherical posterior OZ 8BC offered, 7.6-9.0 in 0.2mm steps Secondary curve, “Lift” (steeper than BC) extends across skirt junction to 9.0mm Adjusting the lift allows fine tuning of the lens design to optimize fit. o Available Parameters BC SC Lift Sphere Power o Patient Candidates 7.60 to 9.00 in 0.2mm steps 8.3mm or 8.6mm L1 (flat), L2 (medium), L3 (steep) +2.00 to -6.00 in 0.25 steps Post-refractive surgery/ post-LASIK patients Post-RK Post-PRK PMD Degenerative corneal conditions or corneal trauma Post-PK and/or Intacts for keratoconus o Fit Select the initial BC Find the mean K of the central 6mm of the cornea. Using the SynergEyes PS Diagnostic set, select the nearest BC steeper than mean K. o E. 36.75/40.75 x035 = 38.75D = 8.71mm o Round to the next steeper BC = 8.6mm. Select the initial lift Begin with the selected BC in Lift “L2” (medium) Apply lens and evaluate the fluorescein pattern as with the SynergEyes A lens. With a successful fit, over-refract to determine the lens power. All diagnostic lenses are plano power. o Ideal SynergEyes PS Fit Apical clearance over central cornea. Optimum fit has little or no touch in the rigid zone of lens- total corneal clearance. Clearance free of bubbles over flattest corneal zone. Light touch at 9mm chord diameter Alignment under soft skirt Soft skirt free of scleral impingement or fluting Lens free to move on lid push-up. o Fluorescein Pattern Insufficient Lift Appropriate Lift o Tips for Achieving Success If bubbles are present, identify the shape and location. If the bubbles are round and located centrally, it is generally due to excessive lift. Flatten the BC. If the bubbles are arc-shaped and located neat the skirt junction, or if bubbles are seen both peripherally and centrally, decrease the lift. If excess touch is observed, note the location of touch area. If touch is central, steepen the BC. If the area of touch is more peripheral, increase the lift. o Additional Fitting Tips Changing the overall sagittal depth of the lens by changing either the BC or the lift allows for maximal customizing of the lens fit. Air bubbles beneath the RGP portion usually indicates a need for less sagittal depth. Areas of excessive touch within the RGP portion indicates a need for greater sagittal depth. If the 8.6mm skirt curve exhibits edge fluting, order the 8.3mm skirt curve. More highly oblate corneas, those with the greatest difference between the central Ks and the peripheral corneal curvature, are more likely to need the steeper Lift (L3). Mildly oblate corneas will likely benefit from the flatter lift (L1), or may even be fit with the SynergEyes A lens design. Post-surgical corneas with ectasia may experience better results with the SynergEyes A or KC designs, depending on the location and amount of ectasia. SynergEyes M o Near center annular bifocal design. o Available Parameters BC SC 7.10 to 8.00 in 0.1mm steps 1.0 (steep), 1.3 (flat) Sphere Power Add Power Add Segment Size +4.00D to -8.00D in 0.25 steps -8.50 to -9.00 in 0.50D steps +1.25, +1.75, +2.25 1.9mm, 2.2mm o Target Patients RGP MF/BF CL wearers Soft MF CL Wearers SV CL Wearers/ MV Patients Patients who wear BF or Progressive Spectacles Emerging Presbyopes o Fit Enter the patient’s flat K values into the window to the left of the SynergEyes Multifocal Slide Rule. The center window will display the appropriate BC and the right window will display the appropriate skirt curve. Turn the slide rule to the reverse side, and with Rx in minus cyl form, enter the patient’s sphere power into the window to the left. Order the lens power that appears in the right window. Determine the patient’s dominant eye, or eye preference for distance and near vision, and then choose segment size. For most patients, select the 1.9 segment for the dominant/distance eye and the 2.2 segments for the nondominant/ near eye. Patients with small pupils or greater demand for distance vision may prefer the 1.9 segments OU while patients with large pupils or a greater demand for near vision may prefer the 2.2 segments OU Determine the patient’s add power by using the chart below Age <50 50-57 >57 Dominant Eye Add +1.25 +1.75 +1.75 Non-Dominant Eye Add +1.25 +1.75 +2.25 Optional If you have a 20 lens set of trial lenses, insert the recommended lenses from the slide rule into tha patient’s eyes. o Over-refract for distance vision. o Use a trial frame with distance over-refraction to demonstrate distance in normal light. o Use hand-helds in either pl, -0.50D or +0.50D to demonstrate near vision. o Adjust parameters if necessary before ordering. o Tips o Note Order lenses It is important for patients to wear the SynergEyes MF lenses for 1-2 weeks to adapt to the new optical system and experience the lenses in their everyday environment. If patient is experiencing unacceptable distance vision Over-refract monocularly with handheld trial lenses and adjust the distance Rx accordingly. Confirm the add power with new distance Rx and reestablish patient’s preferred near focal range. If overrefraction fails to provide acceptable distance vision, o Perform sphero-cylinder over-refraction. o If cylinder is present in over-refraction, perform keratometry or topography over the lens. o If on-eye flexure is observed by over-keratometry or over-topography, order enhanced profile design. If you have confirmed the distance prescription, and you do not observe on-eye flexure, then consider decreasing the segment size on the non-dominant eye from 2.2mm to 1.9mm seg. If the patient is experiencing unacceptable near vision within preferred working distance: Evaluate and determine patient’s near focal range with dispensed lenses. Confirm appropriate distance vision prescription. Re-check near vision with any additional distance prescription adjustment. Use handheld lenses to achieve preferred near vision range and re-calculate patient’s ideal distance and near Rx. Reorder lenses with new parameters. If near vision is unachievable at any distance: Confirm lens centration over pupil. If decentered, consider steeper BC to improve centration. If well centered, consider increasing segment size on the dominant eye. Slight ghosting or reports of “3D” vision upon dispensing are typical effects of a functioning simultaneous vision system. After an adaptive period (typically 1-2 weeks of 8-10 hours of wear), this effect will usually resolve. Patients unable to adapt after 2 weeks may not be ideal candidates for simultaneous vision. Lens Insertion o Always wash and dry your hands using mild lanolin-free soap and a lintfree towel before handling the lenses. o To reduce the risk of switching your lenses, practice handling your lenses in the same order, i.e., always start with your right lens. o To begin, remove the SynergEyes contact lens from the case using the pad of your finger. o Rinse the lens with Optifree Express and inspect the lens for debris or nicks. o With the lens seated bowl-side up on the end of your index finger, pull down the lower lid with your middle finger. o With the other hand, reach over and hold the upper lid by placing the fingers at the bottom of the lashes. o While looking straight ahead in a mirror, place the lens gently on the center of the eye. o Rinse your contact lens case with tap water and air dry. Lens Removal o Make sure your fingers are clean and dry. o Pull down the lower lid of your eye with your middle finger. o Look straight ahead in a mirror or with your head tilted slightly forward o Keep the pads of the thumb and index finger together. o Grasp the lens at the 6 o’clock position. o Allow air underneath the edge and lift the lens away from the eye straight out. Caring for your SynergEyes lenses o 6-month replacement. Lenses are provided in 2-packs. o Solutions o Each day after you remove your lenses, you must digitally clean them prior to overnight storage for disinfection. o Put the lens bowl-side up in the palm of your hand, apply a few drops of Alcon’s Opti-Free Express solution and rub the rigid portion of the lens in a circular motion with the pad of your finger. Be sure to thoroughly digitally clean the entire lens and rinse well. Ignore the “no rub” instructions on some packages. o Rinse the lens while still in the palm of your hand with a steady stream of solution. This keeps the lens clean, clear and comfortable to wear. o Fill your lens case with Opti-Free Express fresh solution and place the lens in the well with the bowl-side up. Never “top-off” or use old solution. Supplemental use of a soft lens daily cleaner or enzyme cleaner may be beneficial. o If using Clear Care, you must use the specifically provided case with the neutralizing disc and soak the lenses a minimum of 6 hours before inserting again. Optisept/Ultracare is also OK. This is actually a little better since there is complete neutralization of the peroxide and there is a new tablet with each use that is coated with HPMC for increased comfort. o SynergEyes contact lenses should be replaced every 6 months. Contact lens cases should be replaced every 3 months. o Opti-Free Replenish is OK for diagnostic lenses, but not for daily use. o Upon follow-up examination, remove the lens and examine the cornea. Case Examples o