Effects of antiglaucoma drugs on the ocular surface in rabbits: a fixed-combination drug versus two concomitant drugs

Abstract

Purpose: We investigated the effects of a fixed-combination antiglaucoma drug and compared it with two concomitant antiglaucoma drugs on the ocular surface.

Methods: Twenty-four rabbits were randomized into four groups. Group 1 was administered timolol, group 2 travoprost, group 3 a travoprost/timolol fixed-combination solution, and group 4 timolol and travoprost. Conjunctival impression cytology specimens were collected at baseline and weeks 1, 3, and 6, and conjunctival biopsy specimens at week 6.

Results: The impression cytology study results were as follows: No statistically significant differences among group 1-3 at any time (p > 0.05); a statistically significant difference between groups 3 and 4 at week 6 (p = 0.003); a statistically significant difference between baseline and group 4 at week 6 (p = 0.008). Conjunctival biopsy specimens of group 1-3 showed no distortion of the conjunctival epithelial structures, but group 4 showed decreased layers of epithelial cells with fewer periodic acid-Schiff (PAS) (+) goblet cells.

Conclusions: A fixed-combination antiglaucoma drug is beneficial in reducing adverse ocular surface changes in long-term use. This is believed to be due to the smaller concentration of preservatives contained in the fixed-combination drug.