Outflow Resistance and Adrenergic Mechanisms

Abstract

Early studies dealing with the effects of stimulation and extirpation of the cervical sympathetic nervous system on the intraocular pressure were concerned mainly with the vascular circulation and the intraocular volumetric effects resulting therefrom. The intraocular pressure alterations frequently included a component related to changes in orbital smooth muscle tone. These studies are summarized in the papers of Greaves and Perkins¹and Davson and Matchett.² The first study of the effects of the sympathetic nervous system on aqueous flow appears to have been made in rabbits by Linnér and Prijot.³They observed that preganglionic cervical sympathectomy had no effect upon intraocular pressure, inflow, or resistance to outflow as measured tonographically; that excision of the superior cervical ganglion had a marked pressure lowering effect 24 hours following operation, after which the intraocular pressure was restored; that constant pressure perfusion of enucleated eyes taken from the side ganglionectomized 24