Effect of Topical Levobunolol on Retinal, Optic Nerve Head, and Choroidal Circulation in Normal Volunteers

Abstract Purpose: Using three different techniques of ocular blood flow measurement, we evaluated the effects of topical levobunolol on retinal, optic nerve head, and choroidal circulation. Methods: Twenty normal volunteers received one drop of levobunolol in one eye and one drop of placebo in the fellow eye. Retinal venous blood flow was measured using multiple scattering laser velocimetry. Retinal capillary blood flow and optic nerve head blood flow were measured by Heidelberg Retina Flowmeter ® . Pulsatile ocular blood flow was measured by ocular blood flow tonography. Changes in blood pressure, heart rate, retinal venous blood flow, retinal capillary blood flow, optic nerve head blood flow, intraocular pressure and pulsatile ocular blood flow were detected from measurements taken at baseline and at 90 to 120 minutes following the instillation. Results: Intraocular pressure decreased significantly in both eyes. Retinal capillary blood flow increased significantly in both eyes. Optic nerve head blood flow increased significantly in treated eyes but remained unchanged in placebo eyes. There were no significant changes in retinal venous blood flow or pulsatile ocular blood flow in either eyes. Conclusion: Our results suggest that one administration of levobunolol may increase the retinal and optic nerve circulation but does not decrease the choroidal circulation.