Certified Ophthalmic Medical Technologist (COMT) Practice Exam

What pathology can lead to blockage of the trabecular meshwork in patients with proliferative diabetic retinopathy?

1. Glaucomatous optic nerve damage

2. Neovascularization of the iris

3. Posterior vitreous detachment

4. Retinal detachment

The correct answer is: Neovascularization of the iris

Neovascularization of the iris in patients with proliferative diabetic retinopathy can lead to blockage of the trabecular meshwork. In this condition, new and abnormal blood vessels grow on the surface of the iris and into the anterior chamber, often stemming from retinal ischemia. When these neovascular structures form, they can spread into the trabecular meshwork, obstructing the drainage of aqueous humor from the eye. This obstruction can increase intraocular pressure and potentially lead to neovascular glaucoma, a serious complication. In contrast, while glaucomatous optic nerve damage may occur as a result of high intraocular pressure, it does not directly cause blockage in the trabecular meshwork itself. Posterior vitreous detachment and retinal detachment also do not create a direct blockage of the trabecular meshwork; rather, they are separate ocular conditions that affect the retina and vitreous body, but do not impede aqueous outflow in the same manner as neovascularization. Thus, neovascularization of the iris is specifically linked to the obstruction of the trabecular meshwork in the setting of proliferative diabetic retinopathy.