Objective: We produced chronic experimental glaucoma in 41 monkey eyes and assessed the long-term effects of elevated intraocular pressure on the presence of, and changes in, peripapillary crescents.
Methods: Three readers independently plotted peripapillary crescent size and location using stereo fundus photographs before and after chronic elevation of intraocular pressure in 41 monkey eyes.
Results: Crescents were found in a majority of normal eyes. After chronically elevated intraocular pressure, new peripapillary crescents developed in only two eyes. Using planimetric analysis, crescent size was enlarged in five (22%) of the 23 eyes with preexisting crescents. Preexisting crescents became more apparent without change in size in a majority of eyes (reader A, 15 [68%] of 22 eyes; reader B, 17 [74%] of 23 eyes; and reader C, 13 [68%] of 19 eyes).
Conclusions: We conclude that peripapillary crescents are often present in normal monkey eyes but that they do not often undergo dramatic changes in size with chronic intraocular pressure elevation. The presence of a crescent was not significantly associated with the development of optic disc cup enlargement in the experimental monkey eye.