The neuroretinal rim in descending optic atrophy.

We studied seven human eyes in which the changes of the neuroretinal rim areas following complete loss of all axons could be measured planimetrically. The mean diminution of the neuroretinal rim area was 40% (range from 26-72%). The optic nerve pathology causing the loss of axons was in the posterior portion of the nerve and the optic disc was therefore not directly disturbed by the injuries. It appears that less than half of the neuroretinal rim is occupied by nerve fibers.