Diagnosing dry eye using a blue-free barrier filter

PURPOSE: To investigate the benefit of the blue-free barrier filter (BF filter) in diagnosing dry eye. DESIGN: Nonrandomized clinical comparison. METHODS: Fifty-three eyes with Sj?gren syndrome (n = 42) or keratoconjunctivitis sicca (n = 11) were enrolled. Fluorescein staining was performed in temporal and nasal conjunctiva, and staining was scored with (BF score) and without the filter (FL score) from 0 to 3. Rose bengal staining was also scored (RB score) similarly. RESULTS: With FL scores of 0, 1, or 2, the BF score was significantly higher: 0.85 +/- 0.37 (P =.031), 1.74 +/- 0.65 (P =.001), and 2.65 +/- 0.48 (P =.001), respectively; with a FL score of 3, the BF score was 3 at all sites. The BF score was superior to the FL score in 66.6% of cases when the FL score was 0 and 1 and in 65.2% when the FL score was 2, but not when the FL score was 3. When the RB score was 0, 1, or 2, the BF score was higher: 1.88 +/- 0.92, 1.78 +/- 0.79, and 2.57 +/- 0.50, respectively (P =.001 for all); when the RB score was 3, the BF score was 2.97 +/- 0.16. The BF score was superior to the RB score in 75.5% of cases when the RB score was 0 and 1 and in 57.8% when the FL score was 2, but not in cases with a RB score of 3. CONCLUSIONS: The BF filter detects damaged conjunctival epithelium stained with fluorescein. Using the filter was beneficial in mild-to-moderate cases, not in severe cases. The BF filter allows diagnosis of dry eye even at the initial stage that is undetectable by conventional observation.