Eyeworld

EW GLAUCOMA 87 From BAK to generics, obstacles to consider F or patients with glaucoma it can be a double whammy—in addition to dealing with the sight- threatening condition, many also suffer from ocular surface disease (OSD). In a recent review published in the May issue of Cur- rent Eye Research, investigators found that OSD affects a sizeable number of patients. About 42% of all ocular hypertension and glaucoma patients were afflicted with OSD, and in 36% of cases this was severe, according to lead investigator William Stewart, M.D., founder, Pharmaceutical Re- search Network, Cheyenne, Wyo. In addition to pointing out the high prevalence of ocular surface disease and the severity of it in these patients, the study highlighted the role of the preservative benzalko- nium chloride (BAK). "Something that has come out in the literature that is interesting and makes sense is that the more medicines a patient is on, the more common and the more severe the OSD is," Dr. Stewart said. "That makes sense because generally they're getting more preservative." He pointed out that several studies conducted by Christophe Baudouin, M.D., Ph.D., professor and chair of ophthalmology, Quinze-Vingts National Ophthal- mology Hospital, Paris, showed that BAK could have a direct toxic or in- flammatory effect on the surface of the eye. "It's sort of a destructive ef- fect that causes all of the irritation and the surface signs," Dr. Stewart said. "If the patient also has dry eye, allergies, or some other inflamma- tory condition, it likely adds to that and makes it worse." Dr. Stewart hopes that the study heightens awareness of the problem. "If you're ten patients behind and the glaucoma patient comes in and his pressure is OK, there's a tendency to think, 'I can get caught up here because the patient can be in and out quickly,'" he said. Given all the medications that may be involved, he urged practitioners to keep in mind that many of these patients may also have ocular surface prob- lems, and if they are suspicious that the dry eye is drug-related, they should do what they can to switch patients to a BAK-free alternative. Clinical perspective Robert Fechtner, M.D., director, glaucoma division, University of Medicine & Dentistry of New Jersey, Newark, said that these study results are consistent with what he finds in practice. "Many patients do fine on their first eye drop and it's not until they get to their second or third that the signs and symptoms of ocular surface disease become evident," he said. He agreed that some patients may unfortunately have a sensitivity to BAK. "The moderate view on this is that BAK has been in eye drops a long time and certainly a number of patients can tolerate it," Dr. Fechtner said. "But in our current era at least half of our patients are on more than one eye drop and we should be aware that the medication itself, as well as the preservative, may influence their ocular surface disease." Louis B. Cantor, M.D., profes- sor and chairman, Indiana Univer- sity School of Medicine, Indianapolis, finds that there are some symptomatic ocular surface patients whose condition is made worse by glaucoma therapy. Then there's another group with a mild, asymptomatic condition that can be tipped over into full-blown ocular surface disease by glaucoma medica- tion. "All they needed was that one more insult to make the house of cards fall and then they became February 2011 October 2011 by Maxine Lipner Senior EyeWorld Contributing Editor Navigating ocular surface disease in glaucoma continued on page 88 Dry eye in glaucoma patients is an all too common phenomenon Source: Robert Fechtner, M.D. 84-88 Glaucoma_EW October 2011-DL2_Layout 1 9/29/11 4:10 PM Page 87

• Cover