EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/82503
74 EW CORNEA September 2012 Device focus New devices for ocular surface disease by Michelle Dalton EyeWorld Contributing Writer An example of how to probe the inferior lid meibomian gland Source: Steven L. Maskin, M.D. From inflammatory mark- ers to plugged meibomian glands, newer tests are helping clinicians diagnose ocular surface disease issues less invasively Editors' note: This article discusses diagnostic tests that have not yet been approved in the U.S. W ithin the past 5 years, researchers have di- rected a considerable amount of time to understanding ocular surface disorders (OSD) and how to better diagnose and treat those dis- orders. "It's a really exciting time for dry eye," said Christopher E. Starr, M.D., assistant professor of ophthal- mology; director, Refractive Surgery Service; and director, Cornea, Cataract, and Refractive Surgery Fellowship, Weill Cornell Medical College, New York. "We now have a firm understanding of the underly- ing etiology, and we know inflam- mation plays an important role in ocular surface disorders." Exactly, said Parag A. Majmu- dar, M.D., associate professor of ophthalmology, Rush University Medical Center, Chicago, and in private practice, Chicago Cornea Consultants. "Clinicians in general are more aware of the issue of dry eye, and technology and pharmacol- ogy are advancing our knowledge base quickly," he said. "We've got a greater understanding of visual out- comes post-surgery and how the surface affects that. We're doing so much premium surgery, we want to be able to provide the best outcomes for our patients, and that's all com- ing back to the roots of OSD." After treating dry eye for more than 20 years, Steven L. Maskin, M.D., founder, Focus on Females Education Foundation, and Dry Eye and Cornea Treatment Center, Tampa, Fla., said he's thrilled about the attention now being directed to MGD, "the most common cause of dry eye and the most challenging to treat." The past 5 years have created "a transformation in our ability to con- trol MGD and dry eye," Dr. Maskin said. "The meibomian glands are a barometer of not just the health of the ocular surface but systemic dis- eases, too." These include allergies, sleep deprivation, autoimmune disorders, and even upper respiratory infections. Dry eye tools "While other specialties have had objective, non-invasive tools to diagnose various conditions, we in the dry eye realm haven't," Dr. Starr said. "The Dry Eye WorkShop report in 2007 changed the definition of dry eye to include both inflamma- tion and hyperosmolarity of the tear film." As a result, clinicians are be- ginning to concentrate on the true pathogenesis of OSD and are appro- priately tailoring their interventions at treating the disease rather than simply the symptoms with artificial tears and lubricants, Dr. Starr said. Dr. Majmudar said a recent study he was involved with found the incidence of routine dry eye in patients scheduled to undergo cataract surgery was around 66%. "It's a huge issue; a lot of sur- gery causes temporary dry eye, but this older population is at a higher risk simply because dry eye tends to be more prevalent in older people, post-menopausal women in particu- lar," he said. While there's "no way" to look at a patient and determine the tear osmolarity, TearLab's Osmolarity System (TearLab, San Diego) "quickly and easily determines the osmolarity content," he said. Much like intraocular pressure in glaucoma, a patient's osmolarity may fluctuate throughout the day, so it's imperative to take more than one reading, Dr. Starr added. "It's a good way to stratify patients based on the results," Dr. Majmudar said, adding he has little firsthand experience with the device. "Tear osmolarity can be useful if you're not certain if the patient has dry eye," Dr. Maskin said. "Its use is more limited once the diagnosis is confirmed because it doesn't guide you toward which type of dry eye [aqueous-deficient or evaporative] the patient has." In general, an osmolarity read- ing of 308 mOsms/L or higher indi- cates the presence of dry eye. And that in and of itself is invaluable in helping with patient compliance, Dr. Starr said. "Patients with other medical conditions tend to be highly vested The Maskin Meibomian Gland Expressor Source: Rhein Medical in their 'numbers'—blood sugar and hemoglobin A1c, blood pressure, cholesterol, etc. … tear osmolarity has become another important number," he said, and people want their numbers to fall back into a "normal" range while being treated. (Ironically, Schirmer's tests also use numbers that are easy to under- stand, but they never caught on with patients or doctors in this same manner, Dr. Starr said.) InflammaDry (Rapid Pathogen Screening [RPS], Sarasota, Fla.) evaluates a specific inflammatory marker—matrix metalloproteinase-9 (MMP-9)—known to be elevated in people with dry eye. "InflammaDry is promising be- cause it can help us diagnose before someone becomes symptomatic. Studies have shown earlier diagnosis and treatment is an important factor in preventing progression," Dr. Majmudar said. The device is cur- rently in clinical trials in the U.S., but has been granted the CE mark. Meibomian gland Obstructed meibomian glands are a leading cause of evaporative dry eye, and the Maskin Probes (Rhein Medical, St. Petersburg, Fla.) can establish and provide physical proof of patency; once those glands are cleared, "it's our task to protect the gland and its functional state," Dr. Maskin said. His Maskin Meibum Expressor (Rhein Medical) includes diamond knurling with double rollers to rapidly express the stagnant oils after probing.