Effects of Topical 2% Dorzolamide(Trusopt(R)) in Q-switched Nd:YAG Laser Induced Glaucoma Rabbits

Hong, Seung Jin; Yoo, Kyung Won; Rho, Sae Heun

Abstract

The purpose of this study is to evaluate the effects of 2% dorzolamide(Trusopt(R)) on the ocular blood flow and retinal microcirculation. To creat an experimental glaucoma model in rabbits and to study the effects of elevated intraocular pressure(IOP), ocular blood flow, retinal effects of elevated intraocular pressure(IOp), ocular blood flow, retinal microcirculation on rabbits eyes, we treated trabecular meshwork of 6 adult pigmented rabbits with Q-switched Nd;YAG laser. And then we investigated the IOP lowering effect, ocular blood flow, and the microcirculation on retina of 2% dorzolamide(Trusopt(R)) in experimental glaucoma model. The IOP, ocular blood flow and the microcirculation were measured with applanation pneumotonography(Alcon, Texas), pneumotonometric probe linked to Langham ocular blood foow system(OBF, Blue mountain) and Heidelberg Retina Flowmeter(HRF). During sustained IOP elevation, 2% dorzolamide(Trusopt(R)) was instilled in one eye and normal saline in the fellow eye. The IOP and ocular blood flow were measured 1, 2, 4 and 8 hours after instillation. The retinal microcirculation was measured 2 and 8 hours after instillation. The retinal microcirculation was measured 2 and 8 hours after instillation at 200micrometer apart from the superior optic disc margin. There were statistically significant reductions in IOP in both 2% dorzolamide(Trusopt(R)) and normal saline-treated eyes(P<0.05). Maximal reduction of IOP was observed 2 hours after single-drop of 2% dorzolamide(Trusopt(R)), with significant reduction of IOP up to 4 hours duration(P<0.05) There was no statistically significant incrsment in ocular blood for even though incrsment was observed 2 hours after single-drop of 2% dorzolamide(Trusopt). There were no change in volume, flow and velocity of blood flow in the peripapillary retina after single-drop of 2% dorzolamide(Trusopt(R))(P>0/1). From the above results, we concluded that 2% dorzolamide(Trusopt(R)) reduced the IOP but did not alter ocular blood flow and peripapillary retinal microcirculation.