What characterizes closed angled glaucoma?

Closed angle glaucoma, also known as angle-closure glaucoma, is characterized by a blockage that occurs in the drainage canals of the eye due to a narrowing or closure of the angle between the cornea and the iris. This angle is crucial because it is where the aqueous humor (the fluid in the eye) drains out. When this angle is too narrow, it can become completely blocked, leading to a rapid increase in intraocular pressure. This condition can cause severe symptoms, including headaches, nausea, and vision disturbances, and requires immediate treatment to prevent permanent damage to the optic nerve.

In contrast, the other options describe different aspects of eye conditions. The slow clogging of drainage canals is more indicative of open-angle glaucoma, which progresses gradually. A wide angle between the cornea and iris would suggest normal drainage function and would not lead to the acute pressure problems seen in closed angle glaucoma. The reduction of eye pressure is not a characteristic of closed angle glaucoma and generally refers to the outcome of successful treatment rather than the condition itself.