Peripapillary crescents and halos in normal-tension glaucoma and ocular hypertension.

In normal-tension glaucoma ("low-tension" glaucoma), 21 of 33 eyes (64%) had a peripapillary chorioscleral crescent or halo, compared with 13 of 38 eyes (34%) with ocular hypertension. The average area of bared choroid and sclera was greater in normal-tension glaucoma (5.8 arbitrary units of area) than in ocular hypertension (1.4 units). Myopic eyes were prevalent among the normal-tension glaucoma group. When eyes with more than 4 diopters (D) of myopia were excluded from the analysis, the difference in prevalence and size of chorioscleral crescents and halos remained. Thus, the presence of a crescent correlates with disc damage, but further work is needed to determine if the correlation represents peripapillary atrophy that accompanies glaucomatous nerve atrophy or represents a greater susceptibility of discs with preexisting peripapillary abnormality.