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. Author manuscript; available in PMC: 2016 Sep 1.
Published in final edited form as: Am J Ophthalmol. 2015 Jun 17;160(3):506–515.e1. doi: 10.1016/j.ajo.2015.06.002

Figure 2.

Figure 2

An illustration of trabecular-iris space area (TISA750), angle opening distance (AOD750), and iris thickness (IT750) measured at 750 μm from the scleral spur. TISA750 was defined as the trapezoidal area with the following boundaries: anteriorly, a perpendicular line between the inner corneoscleral wall and the iris surface at 750 μm anterior to the scleral spur; posteriorly, a line perpendicular to the inner corneoscleral wall extending from the scleral spur to the iris surface; superiorly, the inner corneoscleral wall; and inferiorly, the iris surface. AOD750 was defined as the length of the line extending from the anterior iris to the corneal endothelium, perpendicular to the line drawn along the trabecular meshwork at 750 μm anterior to the scleral spur. For iris thickness, a circle centered at the scleral spur was drawn with a radius of 750 μm, and the point of intersection between the circle and the anterior surface of the iris was identified. The shortest distance from this point to the posterior surface of the iris was calculated as IT750.