Gonioscopes

A gonioscope is a specialized ophthalmic instrument used primarily in slit-lamp biomicroscopy to examine the anterior chamber angle of the eye. The anterior chamber angle is the junction between the cornea and iris, where aqueous humor drains through the trabecular meshwork into the Schlemm’s canal. Gonioscopy is essential for diagnosing and monitoring glaucoma and other angle-related ocular conditions.

Gonioscopes come in various designs, including direct and indirect types. Direct gonioscopes are attached to the slit lamp and provide a magnified, oblique view of the angle. They often feature a wide-angle lens or a mirror to enhance visualization. Indirect gonioscopes, such as the Goldmann three-mirror gonioscope, offer a broader field of view and are useful for assessing peripheral angles. Some models incorporate a panfundus attachment for simultaneous examination of the optic nerve.

The procedure involves applying a topical anesthetic to the eye and positioning the gonioscope at a 45-degree angle to the cornea. The examiner uses a slit lamp to illuminate the angle while observing through the gonioscope. Proper technique is critical to avoid corneal abrasions or discomfort. Gonioscopy helps identify structural abnormalities, such as narrow angles, angle recession, or neovascularization, which may influence treatment decisions.

Gonioscopes are indispensable in clinical practice, particularly in glaucoma care, where angle assessment guides surgical interventions like trabeculectomy or laser peripheral iridotomy. Advances in technology have led to digital gonioscopy systems, improving image capture and diagnostic accuracy. Regular training ensures accurate and consistent use of the instrument.