A 64-year-old man comes to the emergency department due to painless loss of vision in the right eye. The patient's symptoms started suddenly several hours ago and have persisted. He has had no trauma or any similar episode in the past. He has a history of coronary artery disease, atrial fibrillation, and type 2 diabetes mellitus. Blood pressure is 144/86 mm Hg and pulse is 92/min. Cardiovascular examination reveals irregularly irregular rhythm with no murmurs, no peripheral edema, and slightly diminished pedal pulses in both feet symmetrically. Visual acuity in the right eye is hand motion only and normal in the left eye. Funduscopic examination of the right eye is shown in the image below. Which of the following is the most likely cause of this patient's loss of vision?

Question

A 64-year-old man comes to the emergency department due to painless loss of vision in the right eye.  The patient's symptoms started suddenly several hours ago and have persisted.  He has had no trauma or any similar episode in the past.  He has a history of coronary artery disease, atrial fibrillation, and type 2 diabetes mellitus.  Blood pressure is 144/86 mm Hg and pulse is 92/min.  Cardiovascular examination reveals irregularly irregular rhythm with no murmurs, no peripheral edema, and slightly diminished pedal pulses in both feet symmetrically.  Visual acuity in the right eye is hand motion only and normal in the left eye.  Funduscopic examination of the right eye is shown in the image below.  Which of the following is the most likely cause of this patient's loss of vision?

Quizplus · Accepted Answer

11ec160b_3b16_969a_9249_af1af8719af9_MD0001_00 Acute and painless monocular vision loss is characteristic of central retinal artery occlusion (CRAO). The vision loss includes the entire visual field and is often permanent. Funduscopic findings include a pale retina (due to ischemia and edema) and a cherry-red macula (the fovea and foveola are thin and have a separate blood supply from the choroid artery; the red choroid is easily visible underneath). The central retinal artery is a branch of the ophthalmic artery, which arises from the internal carotid artery. Athero- and thromboembolism are the most common causes of CRAO. Predisposing conditions include atrial fibrillation and carotid artery stenosis. CRAO may also be caused by vasculitic diseases (eg, giant cell arteritis). (Choice A) Amaurosis fugax is a painless, transient, monocular vision loss caused by a small embolus to the ophthalmic artery. It usually does not last more than a few seconds. (Choice B) Diabetic retinopathy manifests with blurry vision, black spots, floaters, and decreased peripheral vision. Acute visual loss may occur in the setting of a complication such as vitreous hemorrhage, but this patient does not have evidence of neovascularization or hemorrhage. (Choice C) Large pituitary adenomas may compress the central part of the optic chiasm, causing bitemporal hemianopia. (Choice E) The lower division of the geniculocalcarine tract (Meyer loop), which carries impulses from the lower retina, passes through the temporal lobe. Temporal lobe infarcts involving the Meyer loop cause contralateral upper quadrantanopsia ("pie in the sky" visual defect). Educational objective: Central retinal artery occlusion presents with sudden, painless, and permanent monocular blindness. Funduscopic examination reveals a pale retina and a "cherry-red" macula. __________ References: A review of central retinal artery occlusion: clinical presentation and management. (http://www.ncbi.nlm.nih.gov/pubmed/23470793)

A 64-Year-Old Man Comes to the Emergency Department Due to Painless