## **Core Concept**
Secondary angle closure glaucoma occurs due to conditions that cause the iris to block the drainage angle of the eye, leading to increased intraocular pressure. This can happen through various mechanisms such as pupillary block, plateau iris, or conditions that cause forward displacement of the iris.

## **Why the Correct Answer is Right**
The correct answer, , is a cause of secondary angle closure glaucoma because it leads to pupillary block. In pupillary block, the blockage of the flow of aqueous humor from the posterior chamber to the anterior chamber occurs due to a closed or partially closed pupil. This leads to the iris being pushed forward, which in turn blocks the trabecular meshwork and results in increased intraocular pressure.

## **Why Each Wrong Option is Incorrect**
* **Option A:** is not a well-known cause of secondary angle closure glaucoma.
* **Option B:** does not directly cause secondary angle closure glaucoma through a commonly recognized mechanism.
* **Option D:** might not directly cause angle closure; it could relate to other types of glaucoma or ocular conditions.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is to recognize that conditions causing pupillary block, such as posterior synechiae or a narrow anterior chamber, can lead to secondary angle closure glaucoma. Always consider the mechanism of angle closure when evaluating patients with glaucoma.

## **Correct Answer:** .