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Comparison of short- and long-term effects of betaxolol and timolol on human retinal circulation
A Yoshida1, H Ogasawara, N Fujio
1Department of Ophthalmology, Asahikawa Medical University, Japan.
Purpose:
To determine the short- and long-term effects of betaxolol and timolol on human retinal circulation.
Methods:
In a double-masked, randomised, placebo-controlled study we evaluated the effects of both a one-drop application and a twice-daily 2-week application of either topical 0.5% betaxolol hydrochloride or topical 0.5% timolol maleate on the retinal circulation in 12 healthy volunteers. Laser Doppler velocimetry was used to detect changes in the retinal venous blood flow.
Results:
In both betaxolol- and timolol-treated eyes, intraocular pressure decreased significantly compared with baseline values after both 90 min and 2 weeks. In betaxolol-treated eyes, retinal blood flow did not change significantly after 90 min, but increased significantly (14 +/- 9%; p = 0.02) compared with baseline after 2 weeks. In timolol-treated eyes, retinal blood flow decreased significantly (18 +/- 5%: p = 0.04) compared with baseline after 90 min, and also decreased significantly (14 +/- 6%; p = 0.04) compared with baseline after 2 weeks.
Conclusions:
Retinal blood flow increases as a long-term effect of betaxolol and decreases as both a short- and long-term effects of timolol.