Gonioscopie

Gonioscopie is a diagnostic ophthalmic procedure used to examine the anterior chamber angle of the eye, the region where the iris meets the cornea and through which aqueous humor drains. By visualizing the angle, clinicians can assess the openness of the angle and identify conditions such as angle-closure risk, pigment deposition, neovascularization, or peripheral anterior synechiae.

The examination is typically performed at a slit lamp with the patient seated. Topical anesthesia is used, and a gonioscopic lens placed directly on the cornea provides an optical view of the angle. Common lenses include the Goldmann three-mirror lens and the Sussman four-mirror lens, in conjunction with a coupling fluid or gel to maintain an optically clear contact. The clinician often performs a 360-degree inspection of the angle by rotating the lens and, if needed, uses indentation gonioscopy, applying gentle anterior pressure with the lens to open the angle and differentiate appositional from synechial closure.

Gonioscopy also relies on a standardized grading system to describe angle openness, with the Shaffer scale being the most widely used. Grades range from completely closed (low numbers) to wide open angles (higher numbers), providing a semi-quantitative assessment that guides diagnosis and management, particularly in glaucoma care.

Indications for gonioscopy include evaluation of suspected angle-closure glaucoma, assessment of pigmented or neovascular changes in the angle, monitoring of certain systemic or local conditions affecting the angle, and preoperative planning for glaucoma or cataract surgery. It is often supplemented by non-contact imaging methods such as anterior segment optical coherence tomography or ultrasound biomicroscopy for a more comprehensive assessment.

Complications are uncommon but may include corneal abrasion, infection, or discomfort; proper sterile technique and gentle handling minimize risks.