Gonioscopy is a clinical technique used to examine the drainage angle between the cornea and iris, where aqueous humour leaves the eye. It is fundamental in diagnosing and classifying glaucoma.
Technique
A special contact lens with mirrors or prisms is placed on the anaesthetised cornea while viewed at the slit lamp. This overcomes internal reflection and allows direct visualisation of angle structures such as the trabecular meshwork and ciliary body band.
- Provides information on whether the angle is open, narrow, or closed
- Helps identify peripheral anterior synechiae or angle recession
- Can reveal pigment, neovascularisation, or foreign material
- Requires skill and appropriate patient positioning
Clinical Role
Findings from gonioscopy guide management of open- and angle-closure glaucomas, influence choice of laser or surgical procedures, and help interpret intraocular pressure measurements. It is also important after trauma and in developmental anomalies.
- Performed periodically in patients at risk of angle change
- Findings are often recorded using standard grading systems
- Essential before laser iridotomy or angle-based glaucoma surgery
- Complements imaging from anterior segment OCT or ultrasound
