A 65-year-old man comes to the emergency department due to sudden-onset painless vision loss in the right eye that began several hours ago. The patient says, "It was like a shade dropping over my eye." He had a similar episode 3 months ago that resolved spontaneously after several minutes. He has never seen flashing lights or floaters in his eyes. The patient's medical history includes hypertension and hyperlipidemia. Temperature is 37.1 C (98.8 F), blood pressure is 150/90 mm Hg, pulse is 72/min and regular, and respirations are 14/min. Visual acuity is 20/20 on the left and 20/200 on the right. Funduscopy findings of the right eye are shown below.
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Which of the following is the most likely cause of this patient's symptoms?
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This patient with acute painless monocular vision loss that persists for several hours likely has a central retinal artery occlusion (CRAO), which most commonly begins as an embolized plaque from the ipsilateral carotid artery; a cardioembolic source (eg, due to atrial fibrillation) is also possible. Most patients develop significant permanent visual deficits. Funduscopy can reveal a whitened retina (due to edema) and, in the macula, the central fovea appears red from underlying choroid (cherry red spot). Patients usually have a defect in the afferent pupil reflex.
CRAO is an ophthalmologic emergency, and attempts at recovering vision (eg, anterior chamber paracentesis, ocular massage, revascularization) should be considered. Workup also includes noninvasive imaging of the carotids to evaluate for stenosis. Atherosclerotic treatment (eg, aspirin, statin) and, in cases of cardioembolic phenomenon, long-term anticoagulation (eg, warfarin) are often initiated.
(Choice B) Patients with hypertensive retinopathy typically do not have acute vision loss. On funduscopy, there is focal spasm of arterioles, followed by progressive sclerosis and narrowing. Depending on the severity, arteriovenous nicking, copper or silver wiring, exudates, and/or hemorrhages may be present.
(Choice C) Patients with a detached retina typically have light flashes, floaters, or a curtain across their visual field (usually starting from the periphery rather than dropping vertically, as in this patient) that is not transient. Funduscopic findings can include a wrinkled or detached retina.
(Choice D) Painless, sudden (sometimes subacute) vision loss (or haze) can be seen in central retinal vein occlusion, likely from venous thrombosis. It can progress to an ischemic form that can be painful. Funduscopy usually reveals dilated and tortuous veins leading to scattered and diffuse hemorrhages ("blood and thunder"), disk swelling, and/or cotton wool spots.
(Choice E) Patients with vitreous hemorrhage (eg, due to retinal tear, vitreous detachment) have floaters. Diabetic retinopathy is a common cause. On funduscopy, a hemorrhage is usually seen, but it may also be difficult to visualize the fundus due to obscured details from hemorrhage.
Educational objective:
Central retinal artery occlusion is a monocular painless acute vision loss most commonly caused by an embolized atherosclerotic plaque from the ipsilateral carotid artery.