The histomorphometric study included 22 monkey eyes (Macaca mulatta) that had undergone a temporary experimental occlusion of the central retinal artery. On anteroposterior histological sections through the pupil and the central optic disc region, thicknesses of the cornea and lamina cribrosa were measured in the center, at the periphery, and between the center and the periphery. Additionally, the peripapillary scleral thickness was determined at the optic disc border within the optic nerve meninges and just outside the optic nerve meninges. For outlining the borders of the lamina cribrosa, care was taken to differentiate the anterior lamina cribrosa surface from overlying glial tissue and to delineate the posterior lamina cribrosa from the optic nerve. The reproducibility of the technique had been evaluated in a previous study in which 10 randomly selected histological optic disc sections were reevaluated 10 times.5 The coefficient of variation was 0.14.