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CORNEA/EXTERNAL DISEASE New Noninvasive Method of Assessing the Tear Film Uses Corneal Topography Graphic data greatly facilitate consultations with patients. BY CONNI BERGMANN KOURY, EXECUTIVE EDITOR E ye care practitioners increasingly recognize the importance of identifying and treating underlying problems with the tear film to ensure optimal visual acuity and visual outcomes for surgical patients. In the setting of premium cataract surgery with advanced-technology IOLs, the health of the ocular surface is paramount. Most established methods of examining the tear film are based on the observation of induced tear film reflections. These include determining the height of the tear meniscus, assessing interference phenomena, and observing noninvasive tear film breakup time (TBUT). A limitation of these examinations is their subjective nature.1 In 2007, the Report of the Diagnostic Methodology Subcommittee of the International Dry Eye WorkShop2 provided recommendations for the standardization of methods to examine the tear film and report data in clinical studies of dry eye disorders to improve their comparability. The article indicated that objective methods of analysis might supplement the currently standard tests for examining the precorneal tear film.3 To this end, some manufacturers have begun using imaging technology specifically to obtain dry eye measurements. NONINVASIVE ASSESSMENT The Oculus Keratograph (Oculus, Inc., Lynnwood, WA) has scanning software that can noninvasively assess the tear film, providing both qualitative and quantitative assessments. The test is reportedly quick and relatively comfortable for the patient. 36 ADVANCED OCULAR CARE MAY/JUNE 2011 “The data are produced in an image showing the areas of tear film instability or dry spots.” —Paul Karpecki, OD The Keratograph 4 topographer measures up to 22,000 points using 22 Placido rings and has a true builtin keratometer, according to the product information. Changes in the projected Placido rings (edge shift of the rings) show where the tear film is breaking up (quality of the tear film) within a certain number of seconds of a blink. The data are produced in an image showing the areas of tear film instability or dry spots, said Paul Karpecki, OD, in an interview with Advanced Ocular Care. Dr. Karpecki is clinical director of corneal services at Koffler Vision Center in Lexington, Kentucky. The device also noninvasively measures the height of the tear meniscus (quantity of the tear film). Normative data suggest that the height in a normal eye is greater than 0.2 mm, Dr. Karpecki said. That measurement combined with the noninvasive tear breakup scan can point to dry eye syndrome. Physicians can use the color representation of the tear film’s status to facilitate the consultation and better educate patients, according to Sheri Rowen, MD. She is the founder and medical director of the Eye & Cosmetic Surgery Center at Mercy Medical Center and the Rowen CORNEA/EXTERNAL DISEASE “A picture is worth a thousand words, and the graphic can confirm for patients that their dry eye is a real condition.” —Sheri Rowen, MD Laser Vision & Cosmetic Center in Baltimore. “A picture is worth a thousand words, and the graphic can confirm for patients that their dry eye is a real condition,” she said in an interview with Advanced Ocular Care. “The examination is reproducible by clinical staff, and follow-up testing can confirm the patient’s progress or setbacks with treatment.” The software is also networkable and compatible with electronic medical records. CLINICAL EXPERIENCE When to Use the Keratograph In her clinical practice, Dr. Rowen employs the Keratograph 4 when she encounters a patient who has dry eyes. “Often, my staff will pick up corneal staining, which they are instructed to look for prior to administering drops,” she said. “They will use a fluorescein strip with balanced salt solution and first check the cornea and draw any staining patterns. If they see staining, they will also use a lissamine strip. Then, they would perform the examination using the Keratograph 4 examination, and that way, baseline TBUT is established.” Dr. Karpecki recommends using the device to assess all patients who present with dry eye symptoms when initially taking their history. Both Drs. Karpecki and Rowen employ the technology to examine patients with a history of ocular surface disease and those who are considering any surgical procedure. Dr. Rowen said that, in her practice, these patients are measured with the keratograph every 3 to 6 months to evaluate the effectiveness of treatment. “We see if the TBUT correlates with an improvement in the corneal surface and the patient’s symptoms,” she said. Counseling Patients The data and images obtained with the machine are highly effective for counseling patients, according to Dr. Rowen. “They have something to see, and they know red colors are bad for them,” she said. “They seem to accept treatment regimens more easily and adhere to them with better compliance. The test also helps to pinpoint surface issues preoperatively, so patients might understand a lessthan-perfect outcome if it is due to their tear film.” Dr. Karpecki added that the ability to show patients their images and discuss the height of their tears (tear meniscus) or the rate at which or area where their tear film breaks up is instrumental in gaining their confidence. “It definitely helps to explain the condition in a way they can understand based on images from the Keratograph 4,” he said. “It increases patients’ compliance with the recommended treatment/management knowing that we will compare the images after treatment.” Learning Curve The learning curve associated with the device is not daunting, according to Dr. Rowen. She added that it provides a quantitative measurement of how much the tear film breaks up and when, making the interpretation of the data much easier. Dr. Karpecki agreed. “The dry eye evaluation is relatively self-explanatory, given eye care professionals’ existing knowledge of the tear meniscus height and TBUT,” he said. The only limiting factor is that it can sometimes be difficult for dry eye patients to hold their eyes open for long. “We still can identify their early TBUT, however,” Dr. Rowen noted. CONCLUSION According to Dr. Karpecki, new diagnostic modalities such as imaging technology and other sensitive topography systems can greatly increase the accuracy of dry eye diagnosis. “Because the ocular surface is key to accurate refractions and successful outcomes after cataract and refractive surgery, more accurate early diagnoses of dry eye syndrome will lead to prompt treatment and happier patients,” he said. “I have found [a] very significant correlation among the Keratograph 4, corneal staining, and TBUT, so the device has helped me to better manage these patients,” Dr. Rowen said. ■ Paul Karpecki, OD, is a member of the speakers’ bureau for Oculus, Inc., but acknowledged no financial interest in the product mentioned herein. Dr. Karpecki may be reached at [email protected]. Sheri Rowen, MD, is an assistant clinical professor of ophthalmology at the University of Maryland. She acknowledged no financial interest in the product or company mentioned herein. Dr. Rowen may be reached at (410) 332-9500 or (410) 821-5333; [email protected]. 1. Lemp MA,Marquardt R.The Dry Eye.A Comprehensive Guide. Berlin,Germany:Springer-Verlag;1992. 2. Methodologies to diagnose and monitor dry eye disease:report of the Diagnostic Methodology Subcommittee of the International Dry Eye WorkShop (2007). Ocul Surf. 2007;5(2):108-152. 3. Sickenberger W.Klassifikation von Spaltlampenbefunden.Großostheim: Bezug über Ciba Vision Vertriebs GmbH;2001. MAY/JUNE 2011 ADVANCED OCULAR CARE 37