All of the following anatomical changes will predispose to primary-angle-closure glaucoma except:
**Core Concept**
Primary-angle-closure glaucoma (PACG) occurs when the drainage angle of the eye is blocked, causing a sudden increase in intraocular pressure. The anatomical changes that predispose to PACG include a shallow anterior chamber, a small corneal diameter, and a prominent iris.
**Why the Correct Answer is Right**
The correct answer is related to the anatomical changes that are not associated with primary-angle-closure glaucoma. The most common anatomical changes that predispose to PACG are a shallow anterior chamber, a small corneal diameter, and a prominent iris. A shallow anterior chamber is the most significant risk factor, as it reduces the space between the iris and the cornea, increasing the likelihood of angle closure. A small corneal diameter can also contribute to PACG by reducing the overall size of the eye and increasing the pressure on the drainage angle. A prominent iris can also cause angle closure by pushing the iris against the cornea.
**Why Each Wrong Option is Incorrect**
* **Option A:** A small corneal diameter is a risk factor for primary-angle-closure glaucoma, as it reduces the overall size of the eye and increases the pressure on the drainage angle.
* **Option B:** A prominent iris is a risk factor for primary-angle-closure glaucoma, as it can push the iris against the cornea and cause angle closure.
* **Option D:** A shallow anterior chamber is a risk factor for primary-angle-closure glaucoma, as it reduces the space between the iris and the cornea, increasing the likelihood of angle closure.
**Clinical Pearl / High-Yield Fact**
In patients with primary-angle-closure glaucoma, the intraocular pressure can increase rapidly, causing damage to the optic nerve and potentially leading to blindness. Early recognition and treatment of PACG are crucial to prevent vision loss.
**Correct Answer:** D.