EyeWorld India March 2019 Issue

EWAP SECONDARY FEATURE 25 March 2019 Managing ocular surface issues caused by vision-preserving glaucoma drops by Liz Hillman EyeWorld Senior Staff Writer AT A GLANCE • The effect of glaucoma drops on the ocular surface depends on a patient’s drop regimen, exposure, native dry eye status, presence of preservatives, and more. • Addressing ocular surface issues associated with glaucoma medications can make the patient more comfortable but can also reduce the chance of vision-threatening ocular surface disease. • At some point, surgical glaucoma therapy, such as microinvasive glaucoma surgery (MIGS) options, can help reduce a patient’s drop load and improve the ocular surface. Drops that help protect the optic nerve can be toxic to the ocular surface; experts discuss how to handle this situation “F riends don’t let friends be on four glaucoma medications,” said Steve Sarkisian, MD, glaucoma fellowship director, Dean McGee Eye Institute, and clinical professor, University of Oklahoma College of Medicine, Oklahoma City. Part of this, he continued, is because compliance is “abysmal” for patients on complicated pharmaceutical regimens and also because “the daily assault on the ocular surface by these medications will definitely catch up to you and the patient.” Patients who have this level of topical poly-pharmacy have what Dr. Sarkisian calls “the look.” Their eyes are bloodshot, the lids are crusty, and there is the vacuous stare caused by atrophy of the periorbital fat pads. “It’s not just the cornea, it’s the whole ocular surface, it’s the conjunctival, it’s the sclera, it’s the eye lids,” Dr. Sarkisian said. Dry eye and ocular surface disease is multifactorial, said Marjan Farid, MD, associate clinical professor, Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, but there is a strong correlation with the number of glaucoma drops and years of exposure. All glaucoma drops, said Ali Djalilian, MD, professor of ophthalmology, University of Illinois College of Medicine, Chicago, will have some effect on the ocular surface; whether it’s significant enough for the patient to notice varies. In addition to the number of drops they’re on and for how long, age and preexisting dry eye are all factors that influence the effect of these medications on the ocular surface. What’s more, different drops can have different effects. Brimonidine, Dr. Djalilian said, seems to have the most allergic reactions on the surface. Prostaglandins, on the other hand, seem to be more inflammation inducing and associated with higher rates of meibomian gland dysfunction. Beta blockers are detrimental to the surface as well, though the effect is harder to describe, he continued. “Each is bad in its own way,” Dr. Djalilian said. What most drops have in common is preservatives, which almost always have a negative effect on the ocular surface. Frequently, this preservative is benzalkonium chloride, the negative ocular surface effects from which have been well documented. 1 Preservative-free glaucoma drops do exist— timolol, dorzolamide/timolol, and tafluprost—but Dr. Sarkisian said these options are limited. Dr. Djalilian said preservatives are almost always in generic versions of drops, and most patients, he added, are on generics. Long exposure to preservatives and other agents in glaucoma drops can result in a slow loss of limbal stem cell function, Dr. Farid said. In glaucoma patients who are referred to her for ocular surface disease, Dr. Farid said she will look at their limbal architecture. “The epithelium often looks very beat up and irregular. The epithelium can develop a whorled pattern keratopathy, which is an indication that the limbal stem cells are not working well. It’s beyond your dry eye punctate spots; there is more of a coarse punctate keratitis associated with loss of limbal architecture,” she said. These patients will also often exhibit significant conjunctival hyperemia and/or chronic follicular conjunctivitis, Dr. Farid said, which are “signs that the ocular surface is really in distress.” Dr. Djalilian mentioned cicatricial conjunctivitis as well. “[Limbal stem cell deficiency and cicatricial conjunctivitis] are two blinding conditions that cannot be treated easily once they get to advanced stages,” he said. How to tell whether a patient’s ocular surface issues are a result of their medical glaucoma therapy, Dr. Djalilian explained, can involve taking them off that drop and watching the effect. “My first choice is to try to change their drops around and get them on a regimen that’s gentler on the surface and lets them keep their pressure controlled,” Dr. Djalilian said, emphasizing that any change of glaucoma medication has to be done in consultation with the glaucoma specialist. “Obviously glaucoma takes precedence, except there are some situations where the surface disease can be vision threatening. In those cases, I will push the glaucoma specialist to make the change because this patient is going to go blind because of surface disease if we don’t do anything for them.” Toxic ocular surface disease brought on by glaucoma medication. Source: Marjan Farid, MD Continued on page 26