Experiences with a new procedure for the measurement of the ophthalmic artery pressure: ophthalmomanometry-Doppler.

Abstract

A novel, noninvasive method to determine simultaneously ophthalmic artery pressure (OAP) and flow direction, called ophthalmomanometry-Doppler, is presented. This technique uses a device consisting of a chamber with an apperture hermetically adaptable to the orbital borders. The chamber is equipped with a Doppler probe and an arrival pipe for compressed air connected to a manometer. The OAP measurement procedure consists of applying a pressure in the chamber while the Doppler probe detects periorbital Doppler signals. The systolic OAP corresponds to the Doppler signal disappearance during chamber pressure increase. Studies performed on normal subjects with direct recording of the internal carotid artery pressure (ICP) and indirect determination of the brachial artery pressure (BAP) demonstrated that OAP values assessed by the ophthalmomanometry-Doppler device were highly correlated with simultaneous ipsilateral intra-arterial systolic ICP measurements (r = 0.95, n = 10) and with simultaneous recordings of the BAP (r = 0.85, n = 40). The ophthalmic pressure index (OAP/ICP and OAP/BAP ratio, respectively) ranged from 0.60-0.77 with a mean (+/- SD) of 0.68 (+/- 0.04) in the 50 normal subjects. Preliminary clinical trials show diminished OAP/BAP ratios in patients with occlusive carotid disease ipsilateral to hemodynamically significant lesions. The values obtained on these normal subjects provide baseline data for further investigation of pathologic conditions. This new procedure is simple, convenient, rapid, and safe and provides reproducible information on both OAP and flow parameters, which are important indices in the evaluation of severe carotid artery disease.