Question

Bilateral inferior dislocation of the lens (ectopia lentis) is characteristically seen in which condition?

• A. Marfan's syndrome
• B. Homocystinuria
• C. Weil-Marchesani syndrome
• D. Trauma

Hint:

Direction matters: down and in is metabolic, up and out is connective tissue.

Answer 1

The Correct Option is B

Step 1: Ectopia lentis means displacement of the crystalline lens from its normal position. When the lens lies completely outside the patellar fossa it is luxated (dislocated); when partially displaced but still within the lens space it is subluxated. The direction of displacement points to the cause.

Step 2: In homocystinuria the lens typically dislocates downward and inward (inferonasal), and the involvement is classically bilateral and symmetric. This makes bilateral inferior dislocation the hallmark of homocystinuria.

Step 3: In Marfan's syndrome the lens dislocates upward and outward (superotemporal), the opposite direction, so option a is wrong. In Weil-Marchesani syndrome the lens is small and spherical (microspherophakia) and usually dislocates anteriorly, so option c is wrong. Trauma causes unilateral, irregular displacement rather than a symmetric bilateral inferior pattern, so option d is wrong.

Step 4: Hence the answer is homocystinuria.