A clinical study of peripapillary crescents of the optic disc in chronic experimental glaucoma in monkey eyes
R. J. Derick, L. R. Pasquale, M. E. Pease and H. A. Quigley
Glaucoma Service, Wilmer Ophthalmological Institute, Johns Hopkins University School of Medicine, Baltimore, Md.
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.
