Central retinal artery occlusion presents as sudden profound monocular visual loss. Visual acuity is usually reduced to counting fingers or worse, and visual field may be restricted to an island of vision in the temporal field. Ophthalmoscopy reveals pale swelling of the retina with a cherry-red spot at the fovea (eFigure 7–49). The retinal arteries are attenuated, and “box-car” segmentation of blood in the veins may be seen. Occasionally, emboli are seen in the central retinal artery or its branches. The retinal swelling subsides over a period of 4–6 weeks, leaving a pale optic disk with thinning of the inner retina on optical coherence tomography scans.
Acute central retinal artery occlusion with cherry-red spot (arrow) and preserved retina (arrowheads) adjacent to the optic disk due to cilioretinal artery supply. (From Esther Posner. Reproduced, with permission, from Riordan-Eva P, Augsburger JJ. Vaughan & Asbury’s General Ophthalmology, 19th ed. McGraw-Hill, 2018.)
Branch retinal artery occlusion may also present with sudden loss of vision if the fovea is involved, but more commonly sudden loss of a discrete area in the visual field in one eye is the presenting complaint. Fundus signs of retinal swelling and sometimes adjacent cotton-wool spots are limited to the area of retina supplied by the occluded artery (eFigure 7–50).
Fluorescein angiogram of branch retinal artery occlusion of right eye showing non-perfused superior temporal branch retina artery (outline arrow) and non-perfused retina (solid arrow). (Used, with permission, from S Kiss and Optos plc.)
Identify risk factors for cardiac source of emboli including arrhythmia, particularly atrial fibrillation, and cardiac valvular disease, and check the blood pressure. Nonocular clinical features of giant cell arteritis are age 50 years or older, headache, scalp tenderness, jaw claudication, general malaise, weight loss, symptoms of polymyalgia rheumatica, and tenderness, thickening, or absence of pulse of the superficial temporal arteries. Table 20–12 lists the clinical manifestations of vasculitis.
Giant cell arteritis should be considered in cases of central retinal artery occlusion without visible emboli. Erythrocyte sedimentation rate and C-reactive protein are usually elevated in giant cell arteritis but one or both may be normal (see Chapter 20). Consider screening for other types of vasculitis (see Table 20–11). Screen for diabetes mellitus and hyperlipidemia in all patients. Particularly in younger patients, consider testing for antiphospholipid antibodies, lupus anticoagulant, inherited thrombophilia, and elevated plasma homocysteine.
To identify carotid and cardiac sources of emboli, obtain duplex ultrasonography of the carotid arteries, ECG, and echocardiography with transesophageal studies, if necessary. When indicated, obtain CT or MR studies for internal carotid artery dissection.