New dry eye test assays marker of inflammation

Chicago-A new test for identifying ocular surface inflammation by detecting matrix metalloproteinase-9 (MMP-9) in the tears is an excellent tool to help clinicians diagnose dry eye disease in patients who do not demonstrate the classic clinical findings of this ocular surface condition, said Stephen C. Kaufman, MD, PhD.

MMP-9 is a nonspecific inflammatory mediator that is expressed by stressed epithelial cells, and it has been shown to be elevated in dry eye disease, explained Dr. Kaufman, Lyon Professor of Ophthalmology, University of Minnesota, Minneapolis. As first reported by Dohlman and colleagues in 1969, MMPs are important contributors to ocular surface destruction, corneal ulceration, and perforation.

The test (InflammaDry Detector, Rapid Pathogen Screening), which is not yet available in the United States, is currently on the market in Canada and Europe. It uses an individually packaged, disposable device that is touched to the surface of the eye to collect a tear sample. The results are available in just 10 minutes, and the test is easy to interpret. A positive result occurs when the concentration of MMP-9 in the sample is ≥40 ng/ml and appears as a red line in the test window. Studies evaluating the performance of the test show that it demonstrated specificity of 92% and sensitivity of 87%, Dr. Kaufman said.

“In addition to being quick and easy, this test is relatively inexpensive compared with other new diagnostic tools for dry eye disease,” he said. “The results provide useful information for clinical management by indicating patients who should respond well to anti-inflammatory treatment with topical corticosteroids, topical cyclosporine, or oral doxycycline.”

The test can also be used in follow-up to determine whether anti-inflammatory treatment is effective, he added.

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