Gonioscopy is indispensable for proper diagnosis and management of angle-closure glaucoma. Conventional methods of gonioscopy provide a static image of the configuration of the angle at the particular moment of examination. The extent of occlusion may be determined, but appositional closure cannot be accurately distinguished from synechial closure. This distinction is of considerable importance since an iridectomy is more likely to be successful where synechial closure is minimal.
In 1957 Shaffer proposed a method of operating room gonioscopy immediately after peripheral iridectomy in order to determine the degree of peripheral anterior synechia formation.1 It was based on the premise that appositional closure is reversible and largely eliminated by peripheral iridectomy, whereas synechial closure is irreversible. If most of the angle is found to have opened by virtue of the iridectomy, then the operation is terminated. If extensive adhesions are noted, the surgeon either converts the iridectomy to a filtering
FORBES M. Gonioscopy With Corneal IndentationA Method for Distinguishing Between Appositional Closure and Synechial Closure. Arch Ophthalmol. 1966;76(4):488-492. doi:10.1001/archopht.1966.03850010490005