Pearls Manager: Andrew Tatham
The corneal wedge method is helpful for identifying Schwalbe’s line, a collagen condensation of the Descemet’s membrane. The trabecular meshwork extends posteriorly from Schwalbe’s line to the scleral spur. Angle closure is present if the trabecular meshwork is not seen over 180 degrees or more. Gonioscopy should be performed in a dark room, taking care to avoid light shining across the pupil. To differentiate appositional from synechial closure, indentation or dynamic gonioscopy is essential. In appositional angle closure the angle can be opened when gentle pressure is applied using a small diameter gonioscopy lens on the centre of the cornea.
EGS Guidelines, 4th edition, Page 39.
Reference: Smith SD, Singh K, Lin SC, et al. Evaluation of the anterior chamber angle in glaucoma: a report by the American Academy of Ophthalmology. Ophthalmology 2013;120(10):1985-97.