EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/119916
42 EW FEATURE February 2011 Dry eye/ocular surface April 2013 New formulations seek to protect ocular surface by Erin L. Boyle EyeWorld Senior Staff Writer AT A GLANCE • Approximately 40% of patients have some form of ocular surface disease. • Approximately 70-80% of senior patients, including those with cataract and glaucoma, are estimated to have ocular surface disease. • Half of the glaucoma patient population is on more than one medication, often preserved with benzalkonium chloride (BAK). • A stable tear film can be key to outcomes in ophthalmic surgery across subspecialties. Pharmaceuticals can impact the health of the eye, increasing toxicity exposure N ew pharmaceuticals and supplements for a variety of ocular conditions and diseases are less toxic and more ocular surface "friendly" formulations, which could assist in preserving the integrity of the ocular surface. "Vision starts with the ocular surface. Without a stable tear film, all of the improvements in technology and all the wonderful opportunities that we have for our patients, in refractive surgery, cataract surgery, and glaucoma, are jeopardized by damaging the ocular surface," said Eric D. Donnenfeld, MD, clinical professor of ophthalmology, New York University Medical Center, New York. "When treating any ocular disease, you need to start by looking at the ocular surface as one of the most important aspects of managing that disease. For this reason, ocular surface-friendly pharmaceuticals play an important role in all the disease processes that we manage," he said. Importance The ocular surface is often key to surgical outcomes and patient satis- faction. Toxicity can be a major issue with some ocular medications, especially over long-term use in chronic cases. "Patients are coming in with ocular surface disease … and if we don't have an ocular surface-friendly drug, then we may, while treating the problem, make their ocular surface problem worse. Ocular surface problems have an impact on quality of vision, but also quality of life," said Richard L. Lindstrom, MD, adjunct professor emeritus, University of Minnesota, Minneapolis. He outlined the important qualities for pharmaceuticals that are ocular surface "friendly." The first one is the vehicle for delivery, he said. "We would like to have a vehicle that would be similar to what we would utilize in an artificial tear, which is probably the most ocular surface-friendly drop that we have. The vehicle is important," he said. The next quality is the use of preservatives; the following quality is toxicity levels. "There are medicines themselves that are toxic, for instance, mitomycin-C. Besides the vehicle and the preservatives, the medicine itself would ideally be nontoxic to be ocular surface friendly," he said. An additional quality is effectiveness because the stakes are high: The amount of patients with ocular surface disease is significant. "We looked at all the patients and estimated that about 40% of patients that come to eye doctors have some form of ocular surface disease," Dr. Lindstrom said. "When we look at our senior patients, particularly those with cataract and glaucoma, the incidence of ocular surface disease is probably in the 70-80% range." cally been preserved with benzalkonium chloride (BAK). BAK has been shown in studies to compromise the conjunctiva, he said. However, new formulations are examining preservative-free treatment. Zioptan (tafluprost), the preservative-free prostaglandin from Merck (Whitehouse Station, N.J.), has been on the market about a year, Dr. Lewis said. He said there are several ways of examining the topic. "Obviously we'd like to minimize the interaction of the drugs—a once-a-day drug would be better than a twice-a-day drug; even a drug without preservatives, the less contact you have or need to have, the better. As it applies to the drug itself, we'd like to avoid or minimize the amount of preservatives, and continued on page 44 A significant superficial punctate keratitis associated with generic ketorolac case demonstrates the need for more ocular-friendly drug formulations. Prostaglandin Glaucoma patients are especially susceptible to the results of extended pharmacological use because of the chronic nature of the disease, said Richard A. Lewis, MD, Sacramento, Calif. Half of the glaucoma patient population is on more than one medication, he said. The main class of drugs prescribed for glaucoma, prostaglandin analogues, has typi- Lissamine green image of superficial punctate keratitis following generic ketorolac. Source (all): Eric Donnenfeld, MD