ABO Ophthalmology Complete Practice Exam 2025

Open-angle glaucoma is characterized by a wide anterior chamber angle with a gradual increase in intraocular pressure (IOP). This condition typically develops slowly over time, often without noticeable symptoms in the early stages. The drainage angle remains open, allowing for a wide anterior chamber angle, but the trabecular meshwork, which facilitates outflow of aqueous humor, gradually becomes less effective. This reduced outflow leads to an increase in IOP.

The gradual nature of this process is significant because it allows for damage to the optic nerve to occur without the immediate symptoms that are seen in other types of glaucoma, such as angle-closure glaucoma, which presents with acute IOP spikes and symptoms. In open-angle glaucoma, patients may only notice visual changes after significant damage has occurred, making regular eye exams critical for early detection.

This distinguishes open-angle glaucoma from other types, such as angle-closure glaucoma, which is characterized by a sudden increase in IOP and a narrowing of the anterior chamber angle, leading to acute symptoms. In addition, while loss of peripheral vision is a symptom of open-angle glaucoma, it is not specific enough to define the condition on its own, as other forms of glaucoma can also lead to peripheral vision loss.