BACKGROUND: Although initial patient response to timolol maleate in Gelrite (Timoptic XE) has been generally favorable in clinical settings, anecdotal reports of blurred vision warrant further investigation comparing the tolerability of this new formulation with that of timolol maleate in conventional solution. METHODS: A prospective, double-masked, randomized, cross-over study was performed using 28 normal volunteers who had no evidence of ocular disease, including glaucoma. Mean subject age was 32.5 years. Subjects were randomized to receive one drop in each eye of either timolol maleate in solution (TS) 0.5 percent or timolol maleate in Gelrite (TXE) 0.5 percent. Subjects rated each medication, using a visual analog scale, at the following time intervals: prior to drug instillation, immediately following instillation, 1 min, and at 15 min, 30 min, 1 hour, 2 hours, and 4 hours. RESULTS: Wilcoxon Matched Paris Test showed statistically significant differences at 1 minute for tearing (p = 0.003), blurred vision (p = 0.001) and drug acceptance (p = 0.028) in favor of TS. At 15 minutes and thereafter, however, none of the differences between groups was significant. Visual acuities were unaffected by either TS or TXE. CONCLUSIONS: These data suggest that TXE may impair visual function more than TS, but these effects are briefly and transitory. TXE appears to be a clinically acceptable drug delivery vehicle for use during the young glaucoma patient's waking hours.
