An infant present with bilateral white pupillary reflex. On slit lamp examination a zone of opacity is observed around the fetal nucleus with spoke like radial opacities. The most likely diagnosis is –
**Core Concept**
The question is testing the student's knowledge of congenital cataracts, specifically the characteristic appearance of a cataractous lens on slit lamp examination. The condition described is a typical presentation of congenital cataracts, which are opacifications of the lens that are present at birth.
**Why the Correct Answer is Right**
The described appearance of a zone of opacity around the fetal nucleus with spoke-like radial opacities is a classic finding in congenital cataracts, particularly in the type known as "snowflake" cataract or "zonular" cataract. This type of cataract is thought to be caused by the abnormal development of the lens fibers, leading to the formation of radial opacities that extend from the fetal nucleus to the lens periphery. The presence of these characteristic opacities is a key diagnostic feature of congenital cataracts.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not describe the characteristic appearance of congenital cataracts. The described features are not consistent with a posterior polar cataract, which typically presents as a central opacity in the posterior part of the lens.
**Option B:** This option is incorrect because it does not match the description of congenital cataracts. A cortical cataract typically presents as a spoke-like opacity in the lens cortex, but it does not have the characteristic zone of opacity around the fetal nucleus.
**Option C:** This option is incorrect because it does not accurately describe the appearance of congenital cataracts. A lamellar cataract typically presents as a distinct opacity in the lens lamellae, but it does not have the characteristic radial opacities described in the question.
**Clinical Pearl / High-Yield Fact**
The presence of congenital cataracts can lead to amblyopia (lazy eye) if left untreated. Early diagnosis and treatment are crucial to prevent long-term visual impairment.
**Correct Answer: C. Congenital cataract**