Effects of papaverine on the retinal microcirculation.

Many pathological changes in the retina which give rise to visual deterioration are caused by circulatory disturbances. A number of vaso-active substances have been suggested for the treatment of these disorders in an attempt to increase the flow of blood through the eye. One such substance is papaverine which has been used in the management of acute occlusions of the central retinal artery (Varley, Holt-Wilson, and Watson, I968, Gombos, 1970) and in chronic ischaemic conditions of the choroid and retina, when it has been given by arterial, venous, oral, and retrobulbar routes. Little effort, however, has been made to investigate the action of papaverine on the retinal blood vessels, and, apart from observations by several authors on its dilating effects (Frayser and Hichkam, I965; de Rivas Cherif, I967; Zahn, i966), no quantitative assessment or analysis of the responsc of the retinal circulation to papaverine infusions has yet been reported. The present experiments were designed to measure the effect of both local and systemic administration of papaverine on the retinal blood flow, so that an appraisal of its possible value in the management of retinal vascular disease can be made.