Retinal Artery Occlusion and Acute Choroidal Ischemia

Abstract

Occlusions of the central retinal artery or of its branches are mostly due to an embolism of carotid or cardiac origin. In younger people, inflammatory diseases or thrombophilia may also be involved in rare cases. So far, no treatment has proved effective in restoring visual acuity after these occlusions. However, as the obstruction may be transient or incomplete, or because foveal irrigation may be spared, visual acuity may improve spontaneously in a few cases. A retinociliary artery may be spared by the occlusion, or on the contrary, may be the only artery occluded. An occlusion may also be combined with choroidal ischemia or acute ischemic optic neuropathy. These combinations are often seen in giant cell arteritis, a rare cause of central retinal artery occlusion. The role of the ophthalmologist is mainly to help diagnose the cause of the retinal artery occlusion, in an attempt to avoid subsequent embolism in the central nervous system and/or impairment of the fellow eye. Acute choroidal ischemia is rare, and is mainly diagnosed on fluorescein angiography. Sectorial choroidal ischemia, due to obstruction of the posterior ciliary arteries, may be combined with either acute ischemic optic neuropathy or central retinal artery occlusion, and is very characteristic of giant cell arteritis. Multifocal choroidal ischemia is due to obstruction of the choriocapillaris and causes exudative retinal detachment at the posterior pole. It is mainly seen in the toxemia of pregnancy.