**Question:** Iris pearls are pathognomonic for

A. Pseudoexfoliation syndrome
B. Primary open angle glaucoma
C. Descemet's membrane detachment
D. Primary angle closure glaucoma

**Core Concept:**
Iris pearls, also known as pseudoexfoliation (PEX) material, are characteristic extracellular lamellar deposits found in the anterior segment of the eye. They are composed of alpha-synuclein and are associated with the condition called pseudoexfoliation syndrome (PEX). This condition involves the accumulation of extracellular material in various tissues throughout the body, including the eyes.

**Why the Correct Answer is Right:**
Iris pearls are pathognomonic for pseudoexfoliation syndrome because they directly correlate with the presence of PEX material in the eye. This material is deposited on the lens, cornea, and ciliary body, leading to various ocular complications.

**Why Each Wrong Option is Incorrect:**
A. Pseudoexfoliation syndrome is characterized by iris pearls, not Descemet's membrane detachment. Descemet's membrane detachment is a separate entity involving detachment of the inner layer of the cornea.

B. Pseudoexfoliation syndrome is characterized by iris pearls, not Primary open angle glaucoma (POAG). POAG is a type of glaucoma, while pseudoexfoliation syndrome is a broader condition involving the accumulation of extracellular material in various tissues.

C. Iris pearls are not associated with Descemet's membrane detachment. As mentioned earlier, Descemet's membrane detachment is a different ocular condition.

D. Pseudoexfoliation syndrome is characterized by iris pearls, not Primary angle closure glaucoma (PACG). PACG involves the narrowing of the angle between the cornea and sclera, leading to increased intraocular pressure and damage to the optic nerve.

**Clinical Pearl:** Pseudoexfoliation syndrome is a systemic condition associated with aging and often coexists with other conditions like hypertension, cardiac diseases, and Alzheimer's disease. It is essential for medical students and physicians to recognize this condition as it can lead to various ocular complications and systemic implications.

**Correct Answer: D. Primary angle closure glaucoma**

Iris pearls, or pseudoexfoliation material, are typically seen in patients with pseudoexfoliation syndrome, which is characterized by the accumulation of extracellular material in various tissues, including the eye. These pearl-like structures on the iris are indicative of the presence of pseudoexfoliation syndrome. This syndrome can lead to various ocular complications and should be recognized by healthcare professionals to prevent blindness and visual impairment.