The Effect of 0.5% Timolol Maleate on the Ocular Perfusion of Ocular Hypertensive Patients by Scanning Laser Flowmetry

ABSTRACT

To understand the effect of 0.5% timolol maleate on the ocular perfusion of the optic disc and macula in ocular hypertensive patients, we enrolled 10 males and 15 females without any systemic or ocular disease, except intraocular pressure higher than 20 mmHg. Their average age was 33 ± 13 y/o (range 14-45). Under the randomized, double-masked design, one drop of 0.5% timolol maleate was given in one eye, and placebo in the fellow eye. Heart rate, blood pressure, intraocular pressure, and ocular perfusion were measured at baseline, and then 30 minutes and 2 hours after treatment. Ocular perfusion was measured by Heidelberg Retina Flowmeter (Heidelberg Engineering GmbH, Heidelberg, Germany). We used 10 degree measurement field and 10×10 pixels measurement frame. Four areas were measured, i.e., temporal upper, temporal lower, and nasal parts of the optic disc, and macula. In comparison to the baseline, the treated eyes had a slight reduction of blood flow, volume, and velocity 30 minutes after treatment, but these parameters came back close to the baseline value at 2 hours after treatment. Similar changes were also noted in the control eyes. The results showed that a single drop of 0.5% timolol had minimal effects on the retinal and macular circulation within 2 hours after treatment.