A CLINICAL-STUDY OF PERIPAPILLARY CRESCENTS OF THE OPTIC DISC IN CHRONIC EXPERIMENTAL GLAUCOMA IN MONKEY EYES

Objective: We produced chronic experimental glaucoma in 41 monkey eyes and assessed the long-term effects of elevated intraocular pressure o n the presence of, and changes in, peripapillary crescents. Methods: T hree readers independently plotted peripapillary crescent size and loc ation using stereo fundus photographs before and after chronic elevati on of intraocular pressure in 41 monkey eyes. Results: Crescents were found in a majority of normal eyes. After chronically elevated intraoc ular 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 becam e 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 cresce nts are often present in normal monkey eyes but that they do not often undergo dramatic changes in size with chronic intraocular pressure el evation. The presence of a crescent was not significantly associated w ith the development of optic disc cup enlargement in the experimental monkey eye.