**Question:** Iris pearl is seen in –

A. Glaucoma
B. Cataract
C. Keratoplasty
D. Pterygium

**Core Concept:** Iris pearl is a term used to describe a condition where the iris bulges outwards, most commonly seen in patients with glaucoma.

**Why the Correct Answer is Right:** Iris pearl is associated with open-angle glaucoma, a type of glaucoma characterized by the gradual narrowing of the drainage angle between the cornea and the iris. This narrowing causes increased intraocular pressure, which leads to the bulging of the iris and the appearance of an iris pearl.

**Why Each Wrong Option is Incorrect:**

A. Cataract: Cataract is a clouding of the lens in the eye, distinct from iris pearl in terms of its cause (cataract is age-related) and the affected part (cataract affects the lens, not the iris).

B. Cataract: Similar to option A, cataract is unrelated to iris pearl due to its different causes and affected structures.

C. Keratoplasty: Keratoplasty is a surgical procedure to replace a damaged cornea; it does not involve the iris or result in an iris pearl.

D. Pterygium: Pterygium is a non-cancerous growth on the conjunctiva, the clear covering of the sclera (white part of the eye). Iris pearl is distinct from pterygium due to the difference in the affected structures and conditions.

**Clinical Pearl:** Iris pearl is a characteristic feature of open-angle glaucoma and should be recognized as a crucial sign in clinical practice to suspect and diagnose glaucoma early, enabling prompt treatment and preserving vision.

**Correct Answer:** D. Pterygium

Iris pearl is a term associated with glaucoma, particularly open-angle glaucoma. In contrast, pterygium is a non-cancerous growth on the conjunctiva and is unrelated to the iris or iris pearl.