1984 Volume 4 Issue 3 Pages 297-301
The effect of local-anesthetic stellate ganglion block(SGB) on human retinal blood flow was evaluated in 15 cases using a blue field entoptoscope and ophthalmodynamometer. No significant difference in the mean brachial artery pressure and intraocular pressure was noted between before and after SGB. However, the mean central retinal artery pressure rose by 8.0±4.5mm Hg after SGB. Despite no difference in the speed and number of flying corpuscles (FLC) between the left and right eyes before SGB, both the speed and number of FLC increased after SGB on the side of SGB treatment. On ophthalmodynamometric loading of force onto the eye-ball with a fixed gaze at the blue field entoptoscope, FLC showed no change in both speed and number initially but began to slow down in speed and almost simultaneously in number at a certain force level. Defining the value obtained by subtracting the intraocular pressure (converted from the force level) from the mean brachial artery pressure as a perfusion pressure, the post-SGB perfusion pressure at which FLC began to slow down in speed and number decreased by 8.0±4.1mm Hg from the pre-SGB level.
The above results suggest that SGB induces an increase in retinal blood flow and keep autoregulated retinal blood flow until a lower perfusion pressure. Such SGB-induced changes in retinal blood flow is considered to result from the decrease in the vascular resistance from the heart to the eye but mainly from the elevation of the perfusion pressure when viewed in terms of the ophthalmic artery.
