RETINAL BLOOD-FLOW AFTER SUPERIOR CERVICAL GANGLIONECTOMY - A LASER-DOPPLER STUDY IN THE CYNOMOLGUS MONKEY

There is a conflicting literature regarding the possible presence of a drenergic innervation of the retinal circulation. The effect of a hist ologically confirmed left superior cervical ganglionectomy on the tota l retinal blood how in eight anaesthetised female cynomolgus monkeys w as determined. Near total unilateral ocular sympathetic denervation wa s confirmed by ipsilateral miosis, supersensitivity of pupillary dilat ation to topical phenylephrine and pupillary hyporesponsiveness to top ical hydroxyamphetamine. Retinal vein diameters were measured from mon ochromatic photographs, maximum red cell velocities (V-max) were measu red with a helium-neon laser, using a bidirectional laser Doppler velo cimeter technique, and the total retinal blood how in each eye was det ermined by summation of measurements of flow in individual retinal vei ns. Mean (SEM) total retinal blood flow was 32.93 (1.49) and 30.41 (1. 86) mu l/min in the eight sympathectomised and normal eyes respectivel y; the 9% (5%) difference was not statistically significant. Our study suggests that pharmacologically confirmed sympathetic denervation has little if any effect on resting total retinal blood flow.