HISTOLOGY OF POSTERIOR SCLERAL FORAMEN IN NORMAL EYES - ITS POSSIBLE ROLE IN OPTIC-NERVE DAMAGE IN CHRONIC OPEN-ANGLE GLAUCOMA

We examined the histologic features of the posterior scleral foramen i n 27 enucleated eyes (16 during autopsy and 11 with choroidal malignan t melanoma). The histologic findings of the posterior scleral foramen were similar to those in previous reports. The shape of the scleral fo ramen was either cylindrical or truncated, the latter occurring when t he inner margin of, the sclera projected with a crest-like edge pressi ng into the optic nerve. This configuration was encountered more frequ ently in the upper and lower temporal aspects of the scleral foramen i n 10 eyes, while the nasal rim was free of such projection in all the eyes. We hypothesize that the effect of prolonged high intraocular pre ssure exerted on the axonal tissue against these crest-like edges of t he non-distensible scleral foramen might be the major factor in the et iology of early arcuate nerve fiber bundle defects in primary open-ang le glaucoma.