A child presents with lid lag and an enlarged cornea with a diameter of 13mm. Examination of the eye reveals double contoured opacities concentric to the limbus. Which of the following is the most likely diagnosis –

**Core Concept**
The child's presentation, including lid lag and an enlarged cornea with double contoured opacities concentric to the limbus, suggests a condition affecting the cornea, leading to its enlargement. This is likely due to increased corneal curvature or a corneal abnormality.

**Why the Correct Answer is Right**
The described symptoms are characteristic of **Keratoconus**, a progressive thinning and conical protrusion of the cornea. This leads to increased corneal curvature, resulting in vision impairment. The double contoured opacities concentric to the limbus are known as **Vogt's striae**, which are often seen in keratoconus. The enlarged cornea with a diameter of 13mm is also consistent with this diagnosis.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not provided.
* **Option B:** This option is not provided.
* **Option C:** This option is not provided.
* **Option D:** This option is not provided.

**Clinical Pearl / High-Yield Fact**
Keratoconus is a bilateral condition, often presenting unilaterally initially. A family history of keratoconus may be present in up to 10% of cases.

**Correct Answer:** D. Keratoconus.

✓ Correct Answer: D. Congenital Glaucoma