Effect of beta-blocker eyedrops on corneal epithelial barrier function

To investigate the long-term effect of a topically applied beta-blocker on human corneal epithelium, the corneal epithelial barrier function and the s uperficial cell area of the corneal epithelium were evaluated. Seventeen no rmal healthy volunteers (without medication), 7 cataract patients (treated with pyrenoxine eyedrops) and 7 glaucoma or ocular hypertension patients (t reated with 0.5% timolol maleate) were assigned to this study. The eye-drop s had been used on a daily basis for at least 3 months. In the evaluation o f corneal epithelial barrier function, fluorescein uptake was measured usin g a slit-lamp fluorophotometer after application of 3 mu l of 0.5% fluoresc ein for 10 min. In the evaluation of the superficial cell area, the central corneal epithelium was measured by tandem scanning confocal microscopy (TS CM). The healthy control and timolol groups were compared. Corneal fluoresc ein uptake in the healthy control, pyrenoxine and timolol groups was 20.3 /- 3.2, 21.5 +/- 4.0 and 76.2 +/- 30.0 ng/ml (mean +/- standard error), res pectively. There was a significantly higher fluorescein uptake in the timol ol group compared to the pyrenoxine group (p = 0.0088) and the healthy cont rol group (p = 0.0055). TSCM showed no significant difference in the superf icial cell areas of the corneal epithelium between the healthy control and timolol groups. beta-Blocker eyedrops decreased the corneal epithelial barr ier function. Their application was not accompanied by any biomicroscopic c hange in the superficial cell area. Copyright (C) 2000 S. Karger AG, Basel.