The effects of topical tropicamide and systemic medetomidine, followed by atipamezole reversal, on pupil size and intraocular pressure in normal dogs

Twenty normal Golden Retrievers being screeened for eye, hip and elbow dise ases were given tropicamide topically and medetomidine systemically. Medeto midine effects were later reversed with systemic atipamezole. Pupil size an d intraocular pressure changes were determined. Pupil size increased signif icantly following tropicamide administration and continued to increase slig htly but significantly after medetomidine injection. It was unclear whether the slight increase in pupil size following medetomidine administration wa s due to continued effect of tropicamide or due to the medetomidine itself. Atipamezole did not influence pupil size. Intraocular pressure (IOP) was n ot affected by these drugs. Ophthalmic screening examination for inherited disease following tropicamide administration is equally feasible prior to s edation with medetomidine and after reversal with atipamezole, but not duri ng the period of sedation.