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.
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.
Crescents were found ina 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).
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.
Derick RJ, Pasquale LR, Pease ME, Quigley HA. A Clinical Study of Peripapillary Crescents of the Optic Disc in Chronic Experimental Glaucoma in Monkey Eyes. Arch Ophthalmol. 1994;112(6):846–850. doi:10.1001/archopht.1994.01090180146049