Vascular resistance in primary open angle glaucoma

Abstract

Purpose: To explore any difference in vascular resistance between normal and glaucoma subjects using a continuous wave Doppler technique. Method: The Resistance Index, RI, was calculated in two orbital vessels of 20 glaucoma patients all of whom had pressures over 23 mmHg and 15 age matched normal subjects. The haemodynamic relationship between the supratrochlear and a vessel at the optic disc, presumed central retinal artery, is expressed as RIST/RICRA. Results: In 30 normal eyes the ratio was > 1 m, in 10 glaucoma patients it was > 1. In those glaucoma eyes which were < 1, 14 improved after treatment to > 1. The remaining 16 eyes which showed no change in the ratio were the eyes with moderate to severe field loss. Conclusion: An altered, increased, peripheral vascular resistance with reduced diastolic how in small orbital vessels has been demonstrated in glaucoma subjects. This was not altered by treatment in the more severely affected eyes.