Effects of peribulbar anesthesia on ocular blood flow in patients undergoing cataract surgery

PURPOSE: The effects of extraconal, peribulbar anesthesia on ocular blood f low may be caused by concomitant elevations in intraocular pressure or dire ct pharmacologic alteration of vascular tone. We quantified the effect on o cular circulation with a new technique for assessment of ocular hemodynamic s, METHODS: In a prospective study, ocular hemodynamics were measured before a nd 1 and 5 minutes after peribulbar anesthesia in 22 eyes with age-related cataract. Measurements included fundus pulsation amplitude with a laser int erferometric method assessing the pulsatile choroidal blood flow and mean b lood flow velocity as well as resistive index in the ophthalmic and central retinal artery with Doppler sonography. Systemic blood pressure and pulse were monitored throughout the period of ocular hemodynamic measurements. RESULTS: Fundus pulsation amplitude decreased significantly after peribulba r anesthesia (after 1 minute and 5 minutes: -13% and -8%; P < .001). In the central retinal artery, mean blood flow velocity dropped (-15%; P < .001) and resistive index increased (+3%; P = .02) 1 minute after peribulbar anes thesia compared with baseline. There were no changes in ophthalmic artery h emodynamics. Intraocular pressure was elevated 1 minute after peribulbar an esthesia (+29%; P = .003) but reached baseline values after 5 minutes. CONCLUSION: Pulsatile choroidal blood flow and retinal blood flow velocitie s were reduced after peribulbar anesthesia. These reductions were still pre sent 5 minutes after peribulbar anesthesia, when intraocular pressure had r eturned to baseline values. This supports the theory of drug-induced vasoco nstriction after peribulbar anesthesia. A loss of vision may be a risk of p eribulbar anesthesia in patients who have compromised ocular blood flow bef ore surgery. (Am J Ophthalmol 1999;127:645-649. (C) 1999 by Elsevier Scienc e Inc. All rights reserved.).