An elderly patient complains of recurrent episodes of amaurosis fugax. This is attributable to microembolization of which of the following?
**Core Concept**
Amaurosis fugax refers to a temporary loss of vision in one eye due to transient ischemia, often caused by microembolization of the retinal artery. This condition is a harbinger of larger strokes and requires prompt evaluation.
**Why the Correct Answer is Right**
The retinal artery supplies blood to the retina, and microembolization of this artery leads to ischemia of the retina, resulting in amaurosis fugax. The retinal artery branches off from the ophthalmic artery, which in turn arises from the internal carotid artery. The microemboli that cause amaurosis fugax can originate from atherosclerotic plaques in the carotid arteries or other sources. The transient nature of the vision loss is due to the temporary blockage of the retinal artery, which allows for spontaneous resolution once the embolus passes.
**Why Each Wrong Option is Incorrect**
**Option A:** The facial artery primarily supplies blood to the face and does not directly contribute to the retinal circulation.
**Option C:** The occipital artery supplies blood to the scalp and posterior aspect of the ear, but not the retina.
**Option D:** The posterior auricular artery primarily supplies blood to the posterior aspect of the ear and does not contribute to the retinal circulation.
**Clinical Pearl / High-Yield Fact**
Amaurosis fugax is a warning sign for larger strokes and requires prompt evaluation and treatment to prevent more severe consequences. It is essential to investigate the cause of amaurosis fugax, including carotid artery disease and other sources of emboli, to prevent further ischemic events.
**✓ Correct Answer: B. Retinal artery**