Cilioretinal collateral circulation after occlusion of the central retinal artery

Two elderly patients were noted to have unilateral central retinal arterial narrowing with cilioretinal arterial collaterals supplying the bulk of the flow to the inner retina. One patient had excellent acuity and normal pupillary reactions; the other had marked impairment of vision and an afferent pupillary defect. Both patients were asymptomatic. We suggest that these patients had gradual or partial central retinal arterial occlusion which allowed the development of a collateral arterial supply from the ciliary system.