Figure 2.

(A) Sample image of a mid-horizontal section of a frozen eye with eye shape parameters overlaid. The center of the lens, defined as the intersection of the lens equator with the anterior and posterior poles, was used as the reference point for all measures. The three distances summed to calculate OLs were: anterior chamber depth (AC); crystalline lens thickness (Lens); and vitreous chamber depth (Vitreous). The PPZ was defined as the area including 0° to +18°, centered on the optic nerve head. The zone between 18° and 60° was defined as the peripheral retina. The two large white arrows indicate the approximate off-axis refraction positions. (B) The inset shows an enlargement of the PPZ zone. The dotted line illustrates the location of the traced surface to which OL measures were made.