Which type of glaucoma is caused by a narrow angle that blocks outflow when the pupil is dilated?

Closed-angle glaucoma occurs when the drainage canals of the eye become blocked due to the iris being pushed or pulled forward and narrowing the angle between the iris and the cornea. This situation particularly arises when the pupil dilates, as it can further exacerbate the angle closure, leading to increased intraocular pressure. It is characterized by sudden onset symptoms, including severe eye pain, headache, nausea, and blurred vision. Understanding this mechanism is crucial, as it highlights the significance of the angle between the iris and cornea in managing intraocular pressure and preventing optic nerve damage.

Open-angle glaucoma, in contrast, usually has a more gradual onset and is not primarily related to the angle at which the drainage occurs. Primary glaucoma refers to conditions that occur spontaneously without underlying causes, while secondary glaucoma arises due to another disease or condition affecting the eye, such as inflammation or trauma. These are distinct from closed-angle glaucoma, which is specifically related to the anatomical angle of the eye being compromised.