**Core Concept**
Amaurosis fugax is a temporary loss of vision in one eye, often described as a curtain or shade falling over the eye. It is typically caused by a temporary reduction in blood flow to the retina, which can be due to various factors such as emboli, vasospasm, or other vascular events.

**Why the Correct Answer is Right**
Option B states that amaurosis fugax is a binocular lesion, which is incorrect because the condition typically affects only one eye at a time. Amaurosis fugax is characterized by transient, recurrent episodes of visual loss in one eye, often described as a curtain or shade falling over the affected eye. This condition is usually unilateral, which means it affects only one eye.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is correct in describing amaurosis fugax as transient, recurrent episodes of visual loss. The condition is typically characterized by brief episodes of visual loss that resolve spontaneously.
**Option C:** This option is correct in stating that embolus from the carotid artery is a common cause of amaurosis fugax. Emboli from the carotid artery can travel to the ophthalmic artery and cause temporary reduction in blood flow to the retina, leading to visual loss.
**Option D:** This option is correct in stating that ocular examination may be normal during an episode of amaurosis fugax. The condition is typically characterized by temporary visual loss, and the retina may appear normal on examination.

**Clinical Pearl / High-Yield Fact**
Amaurosis fugax is a symptom of a larger vascular event and should prompt further investigation into the underlying cause. Patients with amaurosis fugax are at increased risk of stroke and should be evaluated promptly for carotid artery disease.

**✓ Correct Answer: B. Binocular lesion. Amaurosis fugax is a unilateral condition.**