Professional and Linguistic Assessments Board (PLAB) Practice Exam

What describes sudden painless loss of vision following a "black curtain" effect that temporarily goes away?

1. Glaucoma attack

2. Amaurosis fugax

3. Central retinal vein occlusion

4. Retinal tear

The correct answer is: Amaurosis fugax

The situation described refers to a temporary loss of vision that presents with a "black curtain" effect, which is characteristic of amaurosis fugax. This condition is often due to a transient ischemic attack (TIA) affecting the optic nerve or retina. The "black curtain" effect describes the sensation of a shadow or a blockage in vision that can often resolve quickly, classically indicating a temporary issue with blood flow or an obstruction. In contrast, the other options present different ocular pathologies. Glaucoma typically results in gradual vision loss and may be associated with pain, rather than an abrupt, painless loss. Central retinal vein occlusion commonly leads to sudden vision loss but is often accompanied by other signs, such as significant visual field deficits or swelling of the optic nerve. A retinal tear can lead to vision problems and may include a curtain-like shadow as well, but it usually does not resolve on its own, and often progresses to retinal detachment if not addressed. Thus, the defining characteristics of amaurosis fugax, particularly the transient nature of the visual disturbance and the temporary loss of vision, align perfectly with the scenario presented.