Retinal Artery Occlusive Disease

Retinal arterial occlusion includes ophthalmic artery occlusion (OAO), central retinal artery occlusion (CRAO), branch retinal arteriolar occlusion (BRAO), from proximal to distal. These can occur with or without retinal ischemia and may be permanent or transient. There are 4 subtypes of CRAO: non-arteritic CRAO (67%), non-arteritic CRAO with cilioretinal artery sparing (14%), transient non-arteritic CRAO (16%), and arteritic CRAO (4%). Non-arteritic retinal arterial occlusions can be embolic (ipsilateral internal carotid artery, heart, aortic arch, or from iatrogenic causes) or non-embolic (thrombophilias, vasculitides, or chronic systemic autoimmune disease, etc.). The most common cause of arteritic retinal artery occlusions is from giant cell arteritis (GCA), which primarily affects medium and large sized arteries. Transient non-arteritic retinal artery occlusions may be due to migrating embolus, transient drops in perfusion pressure, or transient rises in intraocular pressure. CRAO has variable presentation with partial to complete loss of the visual field. Most patients with non-arteritic CRAO have counting fingers vision or worse. Visual acuity varies more widely if cilioretinal artery sparing is present or if it is transient. Arteritic CRAO usually results in 20/200 vision or worse. A cherry-red spot in the macula is found in 90% of patients with CRAO. Other findings include retinal whitening, optic disc pallor, arterial attenuation, optic disc edema, etc. BRAO is often thought to stand for branch retinal artery occlusion, but this is a misnomer as the smaller vessels past the first branching in the retina are arterioles. BRAO usually presents with partial visual field loss, often described as a superior or inferior shade. Patients typically have 20/40 vision or better, but this can be variable depending on the distribution of the affected branch. Retinal whitening in the distribution of the occluded vessel is present 90% of the time. Emboli and retinal vein attenuation can also be observed. OAO usually presents with complete loss of vision (no light perception). Examination will reveal diffuse retinal whitening, absence of cherry red spot, and other fundus findings similar to CRAO. Spectral domain OCT and fluorescein angiography are procedures that can be helpful in diagnosing retinal arterial occlusions. It is important to investigate the underlying cause of the occlusion. Depending on the type of occlusion, MRI, blood testing, carotid imaging, and a heart echocardiogram may be important in the workup of underlying disease. Prompt tissue plasminogen activator (tPA) can be used in cases of non-arteritic retinal artery occlusion. Arteritic retinal artery occlusions require prompt IV corticosteroids. Anti-VEGF therapy or pan-retinal photocoagulation are used to treat secondary neovascularization. Secondary prevention of retinal artery occlusive disease involves managing modifiable vascular risk factors.