Practical tips you can use now - ocular surface changes and dry eye in glaucoma management

November 11, 2007

Ocular surface disease (OSD) is a common complaint in glaucoma practices because of the high prevalence of both conditions in elderly patients and the pattern of medication usage among glaucoma patients. However, addressing OSD while not eroding gains made in treating the glaucoma is a challenge that must be addressed by strategies other than increasing the frequency of dosing with artificial tears or recommending tears with greater viscosity. To adequately manage OSD requires detective work, appropriate intervention, and chair time, said Donald L. Budenz, MD, MPH, professor of ophthalmology, epidemiology, and public health at the University of Miami Miller School of Medicine.

Ocular surface disease (OSD) is a common complaint in glaucoma practices because of the highprevalence of both conditions in elderly patients and the pattern of medication usage among glaucomapatients. However, addressing OSD while not eroding gains made in treating the glaucoma is achallenge that must be addressed by strategies other than increasing the frequency of dosing withartificial tears or recommending tears with greater viscosity. To adequately manage OSD requiresdetective work, appropriate intervention, and chair time, said Donald L. Budenz, MD, MPH, professorof ophthalmology, epidemiology, and public health at the University of Miami Miller School ofMedicine.

Dr. Budenz estimated that about half of glaucoma patients also have OSD. Older age is a factor inthis high prevalence, but daily, long-term use of one or more glaucoma medications containingbenzalkonium chloride (BAK) has a cumulative, negative effect. Clinicians should prescribe non-BAKformulations when possible and consider early laser or surgical therapy for glaucoma patients whoalso have OSD. However, this should only be an option in the presence of indications such as moderateto severe glaucoma, progression at controlled IOP, intolerance to medical therapy, or documentednoncompliance.

Dr. Budenz was one of a panel of experts who spoke during a continuing medical education symposiumheld Sunday evening at the Contemporary Arts Center. The program chairman and moderator was Robert D.Fechtner, MD, director, glaucoma division, Institute of Ophthalmology and Visual Science, New JerseyMedical School, University of Medicine and Dentistry of New Jersey, Newark.

Ocular surface disease may be an underappreciated problem in the glaucoma population because so muchtime and effort has been directed toward lowering IOP at any cost, suggested Terrence P. O'Brien, MD.Chronic dry eye, also known as dysfunctional tear syndrome, encompasses decreased tear volume,abnormalities of tear film composition, and the presence of molecular factors that do not support ahealthy ocular surface. It has many underlying causes and is also influenced by environmentalfactors.

Clinicians can use diagnostic tools such as tear film break-up time, injection, rose Bengal staining,lissamine green staining, fluorescein staining, blink rate, fluorophotometry, and osmolarity, inaddition to the patient's description of symptoms, to verify cases of dysfunctional tear syndrome,said Dr. O'Brien, who is professor of ophthalmology and Charlotte Breyer Rodgers Distinguished Chairat the Bascom Palmer Eye Institute, University of Miami Miller School of Medicine.

Lissamine green is supplanting the other stains as the first choice of many ophthalmologists, Dr.O'Brien said. "This is a vital stain that picks up disease earlier in the course. This is a veryvaluable tool."

Evaluation of glaucoma patients for signs and symptoms of DTS should also include checking for lidmargin disease and meibomian gland dysfunction; foamy tears are a hallmark of the lattercondition.

The need to control IOP typically supercedes that of managing patients' ocular surface complaints,despite the fact that many glaucoma patients also experience OSD, according to Clark Springs, MD,assistant professor of ophthalmology, cornea, cataract, and refractive surgery at Indiana UniversitySchool of Medicine, Indianapolis. Doctors rarely switch controlled patients.

Glaucoma patients are at particular risk of developing OSD because they tend to be at an age wheretear secretion is decreased and take multiple topical and systemic medications. However, many ofthese patients feel that their dry eye complaints are dismissed and may "shop" for a more sympatheticdoctor as they seek relief of symptoms that have a significant impact on their quality of life, Dr.Springs noted. Even when clinicians recognize the symptoms of OSD, they may under appreciate the factthat the very topical medicines that they have prescribed, which are preserved with BAK, arecontributing to the patients' problems.

BAK use is most problematic when patients are using multiple medications with this preservative orbeing treated for chronic ophthalmic diseases, such as glaucoma, with medications containing BAK. Headded that a high concentration of BAK causes dose-dependent cell death and that longer duration ofexposure leads to increased corneal epithelial cell lysis.

Medications with BAK have a negative impact on ocular surface health, cellular physiology, and tearbreak-up time, and when possible the best practice for ophthalmologists is to avoid using them, Dr.Springs said. Several glaucoma medications containing non-BAK preservatives are now available.

Preservatives are found in almost all IOP-lowering medications. However, more agents with nopreservatives or a preservative other than BAK are entering the market, said Richard A. Lewis, MD, aconsultant in glaucoma who maintains a private practice in Sacramento, CA. To date, there is only oneprostaglandin analog with a non-BAK preservative, travoprost ophthalmic solution 0.004% (Travatan Z,Alcon Laboratories). A recent study showed that travoprost with and without BAK was equally effectiveand that there was no change in hyperemia or iris pigmentation with or without BAK.

Dr. Lewis advised clincians to treat glaucoma early and aggressively but at the same time to takeinto account the long-term implications of the treatments they prescribe on the ocularsurface.

Ronald L. Gross, MD, offered several suggestions for clinicians to begin using immediately withpatients who could be at risk for IOP and glaucoma. In every patient, the clinician should not onlycheck IOP but also look at the optic nerve and visual field. Since OSD is common, the clinicianshould also listen to the patient's description of symptoms, look for signs, and ask about drop use.If both glaucoma and OSD are present, the objectives should be to lower IOP while minimizing theimpact on the ocular surface, preferably by using a BAK-free medication.

He also advised clinicians to prioritize therapy based on severity. For example, if glaucoma issevere and OSD is minimal, the target should be lowered IOP. But if glaucoma is minimal and OSD issevere, treating the ocular surface is more important. If both conditions are mild to moderate, whichis the most likely scenario, use a prostaglandin analog to lower the IOP and BAK-free drops to treatthe OSD.

Finally, Dr. Gross recommended that the clinician set reasonable expectations for him or herself andfor the patient. "In patients who don't have that much in the way of signs and symptoms, what you'rereally doing is investing in their future and your future. Their future in that they won't besymptomatic with their disease and your future in that you won't have to mess with their ocularsurface in the future, which is the best outcome you could possibly have," he said.

Dr. Gross is professor of ophthalmology and Clifton R. McMichael chair in ophthalmology at theCullen Eye Institute, Baylor College of Medicine, Houston.

This continuing medical education activity was jointly sponsored by the New York Eye and EarInfirmary and cme², a wholly owned subsidiary of Advanstar Communications Inc., publisher ofOphthalmology Times, and was supported through an unrestricted educational grant fromAlcon.

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