MECHANISMS MEDIATING THE POSTURAL EFFECT OF THE PULSATILE OCULAR BLOOD FLOW

Nicole Vachon

Abstract

An increase in the intraocular pressure (IOP) on assumption of the supine position is a well known phenomenon. More recently however, assumption of the supine position has been shown to be associated with a significant reduction in the pulsatile ocular blood flow (POBF). The physiological mechanism underlying this phenomenon has been suggested as being the change in posture itself and the accompanying decline in the heart rate. The purpose of the present study was to investigate the role of posture on ocular rigidity, duration of the cardiac cycle, and the POBF. Twenty-five healthy young adults, 20 to 35 years of age, served as subjects. Ocular rigidity was assessed by measuring the IOP before and during an IOP increase induced by a 10gm weight added to a probe of a Digilab pneumatonometer, and correlated with measures of the POBF derived with a Langham OBF system. Ocular rigidity and POBF were measured for the seated and supine positions, and the postural response calculated as the difference in the values obtained in the seated and supine positions. While the POBF (t=4.988, pRESIDUAL ASTIGMATISM WITH BITORIC RIGID GAS PERMEABLE CONTACT LENSES WITH SPHERICAL POWER EFFECT: A COMPARISON OF FOUR DIFFERENT DESIGNS

Details

Year: 1992

Program Number: Poster 24

Author Affiliation: n/a

Co-Authors: Angela Kothe

Co-Author Affiliation: n/a

Room: Great Hall