Gonioscopy

Viewing the drainage angle of the eye

Overview

Gonioscopy is an examination of the anterior chamber angle, where the iris meets the cornea and where the trabecular meshwork drains fluid from the eye. Because the angle cannot be seen directly due to total internal reflection, a special mirrored contact lens is placed on the numbed eye during a slit lamp examination. It is the standard way to classify glaucoma as open angle or angle closure, to identify eyes at risk of angle closure, and to find abnormalities such as new blood vessels, pigment, or injury related angle recession. It is a routine part of a comprehensive glaucoma assessment.