EyeWorld Asia-Pacific March 2017 Issue

EWAP SECONDARY FEATURE 27 March 2017 and there are several strategies to do this. First, Dr. Kammer said to reduce the total number of drops. “This can be achieved by preferentially prescribing glaucoma drops that can be dosed once daily (like beta blockers and prostaglandin analogs),” he said. The use of fixed-combination preparations can also be increased. “There is strong clinical data that suggests that fixed combination glaucoma drops have a better safety profile and tolerability compared to when the medications are used separately,” he said. Dr. Kammer stressed the need for early use SLT, which can produce a drop in IOP that is comparable to pharmacologic treatment while avoiding the preservative-induced toxicity to the ocular surface. “I also consider using oral carbonic anhydrase inhibitors (CAIs) in selected individuals,” he said. “This is a bit controversial because oral CAIs have been documented to occasionally exacerbate dry eyes, particularly in the elderly, whose body water content is lower compared to younger individuals.” However, for younger patients, those with significant sensitivity or intolerance to preservatives, and those who don’t have the dexterity to instill eye drops, this is a reasonable option, he said. “In many individuals, the benefits of a reduced BAK load outweigh the mild dehydration caused by the oral CAI.” Another option, Dr. Kammer said, is to use eye drops that are either preservative-free or utilize non-BAK preservatives. From a clinical perspective, the glaucoma medications that use less toxic preservatives are well tolerated and often result in an improvement in symptomatology, particularly if these patients have preexisting ocular surface issues, he said. Another way to minimize the BAK burden is to use a preservative-free formulation. “Due to the significant risk for contamination in multidose bottles, the only practical way to accomplish this is with the use of single-dose units,” Dr. Kammer said. “While the lack of any irritating preservative is a boon for patients, this option tends to be much more expensive, and some patients (particularly the elderly) have difficulty handling the small vials.” Many patients will be fine with preserved glaucoma medications. But a certain segment of the population benefits particularly from minimizing BAK exposure including those with a preexisting dry eye or ocular surface disease; a documented intolerance to preservatives; an existing multidrug treatment regimen; and treatment that is expected to last many years. Tests to perform Dr. Weissman said many of the tests used for dry eye disease are important for these patients as well, including tear break-up time, Schirmer’s test, topography looking at the corneal surface, and tear osmolarity. “The most important thing is adding one drop at a time,” she said. If the patient has a very high pressure, you may have to add more than one. By adding one at a time, you can see what the corneal surface does, Dr. Weissman said. If there is more dryness after one, switch to preservative-free, she suggested. It’s also important to make sure the patient is lubricating the eyes frequently with preservative-free artificial tears. Topography is important to have readily available to look for distortion on the corneal surface, Dr. Weissman said. Staining is also helpful to see if there’s keratopathy on the exam that can show how dry the eyes are. Dr. Weissman added that serum tears are a useful option. With these, the patient’s blood is drawn, spun down, and teardrops are formulated from the blood. They have an anti-inflammatory effect and can be helpful in patients with both glaucoma and severe dry eye, she said. Impact of OSD on astigmatism measurements There may be a concern that ocular surface problems can make astigmatism measurements less accurate in glaucoma patients. Dr. Wallace said that in order to get the best visual outcomes after cataract surgery, she brings the patient back in for IOL calculations on a separate preop visit where measurements are performed before any drops are placed in the eye. “We also may start a prescription medicine to treat the dry eye about a month before surgery,” she said. Dr. Weissman uses topography to help account for these potentially inaccurate measurements, as it helps her to evaluate the patient better. EWAP Editors’ note: Dr. Kammer has financial interests with Allergan (Dublin, Ireland). Dr. Realini has financial interests with Allergan, Bausch + Lomb (Bridgewater, New Jersey), and Alcon (Fort Worth, Texas). Dr. Wallace has financial interests with Allergan. Dr. Weissman has no financial interests related to her comments. Contact information Kammer: jeff.kammer@vanderbilt.edu Realini: hypotony@gmail.com Wallace: danajwallace@gmail.com Weissman: heather.m.weissman@gmail.com