INCREASE OF RETINAL NERVE-FIBER LAYER THICKNESS IN OCULAR HYPERTENSIVES WITH TIMOLOL THERAPY

Purpose: The purpose of this study was to determine whether timolol dr ops compared to placebo drops had a significant effect on retinal nerv e fiber layer thickness in ocular hypertensives. Methods: Thirty-seven ocular hypertensives were randomly assigned to receive placebo or 0.5 % timolol drops to both eyes for 18 to 24 months in a double masked cl inical trial. Measurements of ocular pressure and pho to graphs of ret inal nerve fiber layer using stereophoto grammetric techniques were ma de at about 3 month intervals for 18 to 24 months of follow-up. Result s: None of the subjects developed visual field loss when tested with t he Goldmann perimeter by kinetic and static means at six month interva ls. Subjects treated with timolol had a significant decrease in ocular pressure and developed a significant increase in retinal nerve fiber layer thickness compared to subjects treated with placebo. Multivariat e analyses indicated that the increase of retinal nerve layer thicknes s was not associated either with the ocular pressure on treatment or t he decrease in ocular pressure on treatment. Conclusion: Timolol treat ment was associated with an increase of retinal nerve fiber layer thic kness. The effect of timolol appears to be related to mechanisms other than the decrease in ocular pressure.