Sustained perimacular vascular and visual response to topical beta blockers in normal human eyes

Abstract

Purpose: To assess visual and circulatory responses to treatment with topical beta adrenergic antagonists. Design: Institutional prospective randomized clinical trial in normal adults. Methods: Twenty adults (36 (mean) ± 8 (S.D.) years) underwent repeated baseline perimetry (Humphrey 30-2), contrast sensitivity (Vector Vision), perimacular microcirculatory studies (Oculix blue-field entoptic simulator), intraocular pressure (IOP), heart rate (HR), and blood pressure (BP) testing. Subjects commenced either timolol 0.5% or betaxolol 0.5% twice daily on day 1, were retested on days 3 and 35, discontinued treatment for 21 days, whereupon repeated tests were performed. Treatment responses were compared by paired t-test. Results: Timolol-treated eyes showed improvement in contrast sensitivity ( P=0.03) and pericentral perimetric thresholds ( P=0.01), but corresponding increases among betaxolol-treated eyes were significantly higher ( P=0.03 and 0.04, respectively, relative to timolol-treated eyes). Leukocyte velocity increased with both drugs, each with post-withdrawal carryover ( P≤0.03). Significant IOP reduction (∼2.5 mmHg) occurred in both groups, BP fell 2.8 mmHg among betaxolol-treated subjects ( P=0.02), and HR was 2 bpm slower among timolol-treated subjects ( P=0.03), but all reverted to baseline values after washout. Conclusions: Both treatment groups demonstrated significant changes in visual function and perimacular hemodynamics, sustained after the terminal 3-week washout period.