EyeWorld Asia-Pacific June 2015 Issue

57 EWAP PHARMACEUTICALS June 2015 BAK-induced epithelial keratitis is highlighted using uorescein staining. Source (all): Jeffrey A. Kammer, MD by Maxine Lipner EyeWorld Senior Contributing Writer Scanning the glaucoma field Considering how medications impact the surface I t is an all too common issue for glaucoma patients: ocular surface problems. While approximately 15–20% of elderly patients have some type of ocular surface disease, for those with glaucoma the incidence rises to about 40– 50%, according to Jeffrey A. Kammer, MD , associate professor of ophthalmology, Vanderbilt University, Nashville, Tenn. “Unfortunately, we’re so geared toward watching the pressure, checking the visual field, and looking at their OCT or for any optic nerve head changes that we sometimes overlook these problems that patients almost always discuss,” Dr. Kammer said. Patients often refer to symptoms such as foreign body sensation, redness, blurred or fluctuating vision, and scratchiness, he said. Irritation issues Glaucoma patients even without medication have been found to have a higher rate of ocular surface disease and dry eye, Dr. Kammer noted, adding that the pressure-lowering drops can exacerbate the problem. “Glaucoma medications can have both short-term and long- term effects on the ocular surface,” he said. In the short term, he finds, medications can disrupt the tear film. From a long-term perspective, they can affect the goblet cells, cause fibrosis, and disrupt the epithelium, he said. Parag Parekh, MD , Laurel Eye Clinic, Brookville, Pa., also finds that surface issues are a problem for many patients. “I put patients on a drop and typically I have them back 1 month later to see how they’re making out,” he said. In addition to considering whether the drop lowered the patient’s pressure, he looks into just how well the medication is being tolerated. “Some people have a reaction right away and some are OK the first few weeks, and then another month or two goes by and they have a reaction to it,” he said. There are multiple factors involved here, Dr. Parekh said. The vehicle that the medication is in often has BAK (benzalkonium chloride). “That substance hitting the surface of the eye again and again for days, weeks, months, and years on end can cause irritation to the surface of the eye,” he explained. Also, the medication itself can potentially cause dry eye and irritation, he said. Dr. Kammer agreed that not just the preservatives but also the medications themselves can be a factor. “Prostaglandins, because they can be pro-inflammatory, can certainly be more harsh on an eye that has a compromised ocular surface to begin with,” he said. “But to be fair, any of the medications have the potential of aggravating clinical dry eye syndrome.” With any glaucoma patient who has underlying dry eye or ocular surface disease, Dr. Kammer recommended aggressively treating patients from the start with lid hygiene, as well as use of flax seed oil, doxycycline, artificial tears, and Restasis (cyclosporine, Allergan, Irvine, Calif.). “We should get them into the best situation before throwing on all of our other medications, which will exacerbate their disease,” Dr. Kammer said. “We should treat them aggressively from the get- go so that they’re better able to tolerate these medications once we institute treatment.” Avoiding BAK Dr. Kammer tries to take the medications themselves into consideration. This often means focusing on the preservatives used. “Certainly the most common preservative that’s used today is BAK and this is a detergent, so it can have a significant negative effect,” Dr. Kammer explained. “Just like it disrupts the bacterial cells or viral cells or fungal cells, it can also disrupt the cells on the ocular surface.” This has been seen on a molecular level during in vitro studies and has often been seen clinically as well, he said. That has led to the rise of continued on page 58 Signi cant corneal irritation (epithelial irregularity) can be visualized using direct illumination through the slit lamp