The configuration of peripapillary tissue in unilateral glaucoma
J. Nevarez, E. J. Rockwood and D. R. Anderson
Bascom Palmer Eye Institute, University of Miami School of Medicine, FL 33101.
We compared the peripapillary scleral and choroidal halos and crescents in
the two eyes of 42 patients with unilateral glaucoma. In most cases, the
edge of the three tissue layers (the retinal pigment epithelium [RPE], the
choroid, and the sclera) that encircle the optic nerve head of the
glaucomatous eye superimposed exactly on the mirror images of the edges in
the fellow nonglaucomatous eye. Although the size of the peripapillary
crescent or halo was the same in both eyes, it and the scleral rim were
often more conspicuous in the eye with glaucomatous damage because the
tissue edges were seen more easily through the reduced thickness of nerve
fiber layer tissue. There were nine exceptions. In five cases, the
peripapillary choroidal crescent (the area of choroid not covered by RPE)
was larger in the glaucomatous eye. In four eyes, however, the crescent was
larger in the nonglaucomatous eye, although the magnitude of the asymmetry
was less in these four cases. Thus, in late stages of optic nerve damage,
there was some RPE atrophy, but in most cases of glaucoma, the area of
bared choroid was the inherent anatomic configuration of the optic nerve
exit canal.
