discovering dry eye
News from the American Academy of Optometry Meeting
BY BARBARA CAFFERY, OD, MS, FAAO
The American Academy of Optometry meeting was held in San Diego in December, and a number of papers were presented on dry eye disease. As usual, many papers presented more questions than answers, but the questions are still very interesting.
Sjögren's and Staining
I presented an observational paper which reviewed two years of newly diagnosed Sjögren's syndrome patients and found that a substantial number of them had no corneal staining. These patients had no substantial differences in their conjunctival staining. My question: Are these non-stainers truly different? Perhaps I caught them on a particular day, and if I saw them one week later would they stain as the others. If they are different, how are they different: "stronger" corneal epithelial cells? Different inflammatory chemicals in the tear film? Different osmolarity of the tear film? I will continue to observe these patients and try to answer some of those questions.
Chalmers et al presented the work of several investigators who saw normal, dry eye and Sjögren's syndrome subjects after they had completed several questionnaires. Asking patients about their ocular surface symptoms is very important in dry eye diagnosis. Sensitivities for questions of frequency (sometimes to constant) and severity (moderately to extremely bothered) were in the high 80s and 90s on a scale of 100. Interestingly, after performing a number of dry eye tests, these clinicians would rate the patients' severity of dryness by symptoms more than signs. Those of us who deal with dry eye patients daily will likely agree with this clinical perspective.
Dry Eye Treatments
Treatments were also investigated. Tomlinson et al used artificial tears in hydrogel lens wearers in an attempt to improve vision but found no change in contrast sensitivity with the use of these drops. Lehman et al from Indiana University observed tear film break-up before and after artificial tear usage and found no improved stability or reduced symptoms with drop use.
Three different topical treatments for dry eye were reported at the meeting. Hyaluronic acid based drops were investigated by Berke et al. Dry eye subjects were asked to use the drops four times per day. After seven days, these subjects presented with reduced lissamine green staining and reduced symptoms of dryness. No controls were used. Researchers from Allergan presented results on Refresh Endura, its new emulsion-based dry eye treatment which contains polar oils that increase the lipid layer stability. This double-masked study showed that after 90 days, subjects reported improvement in symptoms, and clinicians noted fewer signs of dry eye disease. Finally, skin cream with and without testosterone was applied to the lids of 20 dry eye subjects in a study by Connors. Post-menopausal females benefited the most from the use of the cream. They had greatly reduced symptoms of dryness and could wear their contact lenses longer.
And so we continue to observe and ask the right questions regarding the tear film and dry eye disease. Diagnosis remains difficult but clearly requires asking the right questions. Treatments are in development which may finally make a difference in the quality of life of our dry eye patients.
Dr. Caffery has practiced optometry in Toronto, Canada, in a group setting dedicated to contact lens and tear film research since 1977.