Effect of topical dorzolamide on tissue circulation in the rabbit optic nerve head.

PURPOSE To examine the effect of 1% topical dorzolamide on tissue circulation in the optic nerve head (ONH) of Dutch rabbits. METHODS A laser speckle tissue circulation analyzer was used. One eye of each rabbit received 1% topical dorzolamide twice daily for 20 days, and the fellow eye received the vehicle in a masked, randomized manner. Intraocular pressure (IOP) was measured every 5 days. The normalized blur (NB) value, a quantitative index of tissue blood flow velocity in the ONH, was measured before treatment and 2 hours after the last instillation on the 20th day. RESULTS The IOP was lowered by about 2 mm Hg only in the dorzolamide-treated eyes (P < .01). The NB value showed no significant change in either dorzolamide-treated or vehicle-treated eyes. CONCLUSIONS Long-term topical dorzolamide does not affect the ONH tissue circulation in dorzolamide- and vehicle-treated eyes of Dutch rabbits.