Development and aging of the eye in mice with inherited optic nerve aplasia: histopathological studies.

We have examined the morphological development of optic nerve aplasia in a subpopulation (10-20%) of anophthalmic mice (Strain ZRDCT -AN) that develop microphthalmia. During embryonic stages the optic fissure in microphthalmic mutants did not involute into the optic stalk. Even in the absence of a proper fissure, early differentiation of the various retinal elements was not disturbed. Subsequently, however, the optic nerve fibers failed to exit from the eye in their appropriate position. Secondary changes in the retina, probably resulting from a failure of optic axons to reach their central targets, were near total loss of ganglion cells and variable attenuation of the other nuclear and plexiform layers. Retinal rosettes were also commonly present.