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EW FEATURE 62 Glaucoma and the cataract patient • February 2017 AT A GLANCE • Patients often have the most issues tolerating medications with preservatives, so a preservative-free option might be best for patients with ocular surface problems. • Selective laser trabeculoplasty or a MIGS procedure may be good options for these patients. • Using topography and other tests can help the surgeon ensure accuracy in these potentially challenging cases. by Ellen Stodola EyeWorld Senior Staff Writer patients with mild to moderate glau- coma that I may offer to patients who are poorly tolerating drops and who are appropriate candidates," she said. Eliminating or decreasing the drop burden on patients with OSD is critical, she said. "I always start with selective laser trabeculoplasty (SLT) but also consider glaucoma surgeries (particularly MIGS), as the addition of further drops usually exacerbates the OSD problem," Dr. Wallace added. can be irritating. Many drops are irritating that have nothing to do with preservatives, he added. For example, dorzolamide is only solu- ble at a pH of 5.6, Dr. Realini said, which is like lemon juice, so it will sting when you put it into the eye. Glaucoma management in patients with OSD Dr. Wallace recommends laser tra- beculoplasty at an early stage to all patients with OSD. "With the rise of microinvasive glaucoma surgeries, we have more surgical options for cells, and a dropout of the meibo- mian glands," he said. "Glaucoma is another disease that becomes more common with advanced age, so it is not surprising that there is a high comorbidity rate between these two processes." When patients suffer from OSD, any medication that they place in their eye can cause discomfort, Dr. Kammer said. The patients also have the most difficulty tolerating drops that contain preservatives, particu- larly benzalkonium chloride (BAK), which is a quaternary ammonium compound whose antimicrobial activity stems from its ability to disrupt cell membranes, thereby po- tentiating the cell death process, he said. "Multiple studies have reported on the deleterious effects that BAK has on conjunctival epithelium, corneal epithelium and the corneal stroma," Dr. Kammer said. "It can also elicit a significant pro-inflam- matory response on the ocular sur- face, which can further exacerbate the health of the ocular surface." The more BAK that you use, the more ocular surface toxicity will de- velop, he said. This is seen in many glaucoma patients who use multiple glaucoma drops that contain BAK. "Fortunately, studies have found that reducing the BAK load can have a beneficial effect on the health of the ocular surface and tolerance of topical glaucoma medications," he said. Preservative-free eye drops are the best tolerated, Dr. Wallace said, although even these are not free of side effects for people with ocular surface disease. The majority of the time, all glaucoma medications cause a form of dry eye, Dr. Weissman said, espe- cially if you add multiple medica- tions. She added that brimonidine seems to have more of a reaction than other medications. Dr. Weissman agreed that pre- servative-free glaucoma medications are better tolerated. However, they're more difficult for patients because they usually need to be refrigerated and often come in vials that can be hard to open for some. Many therapeutic choices made are contributory to patients' symp- toms, Dr. Realini said, and almost any drop has something in it that Experts discuss how ocular surface disease may be a factor when choosing a treatment plan in glaucoma patients T reating the ocular surface is extremely important, but for those patients with both ocular surface problems and glaucoma, it becomes even more important to consider how the ocular surface may be impacted by glaucoma medications and surgery. Dana Wallace, MD, Thomas Eye Group, Sandy Springs, Georgia; Heather Weissman, MD, Atlanta Ophthalmology Associates, Atlanta; Jeffrey Kammer, MD, Vanderbilt Eye Institute, Nashville, Tennessee; and Tony Realini, MD, associate professor of ophthalmology, West Virginia University, Morgantown, West Virginia, discussed approach- es to glaucoma management in patients with ocular surface disease (OSD). Glaucoma medications First, Dr. Kammer said, physicians must acknowledge that ocular sur- face disease is a real problem in glau- coma patients. "In the United States, it is estimated that roughly 15% of all individuals over the age of 65 have some form of OSD," he said. It's also important to be aware of the population. "Many of our glaucoma patients are elderly, so they are at a higher risk of dry eyes to begin with, secondary to decreased age-related tear secretion, a decrease in goblet Treating ocular surface problems in glaucoma patients Ocular surface disease and glaucoma may occur together and can be a real problem for patients. In these patients, it's important to carefully choose medications and a surgical plan. Source: Robert Fechtner, MD

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