This document discusses different methods for measuring intraocular pressure including the Schiotz tonometer, Goldmann tonometer, Perkins tonometer, pulse air tonometer, Tono-Pen, and Tonopen. It also describes gonioscopy, the technique used to examine the anterior chamber angle. Normal intraocular pressure ranges from 12-22 mmHg and increased pressure can damage the optic nerve and lead to vision loss from glaucoma. Gonioscopy allows visualization of structures in the anterior chamber angle like the root of the iris, ciliary band, and scleral spur.