The mechanism of disc pallor in experimental optic atrophy. A fluorescein angiographic study
R. L. Radius and D. R. Anderson
Ascending optic atrophy was produced in 13 eyes of owl monkeys
(Aotestrivirgatus) by retinal photocoagulation. Color fundus photography
and fluorescein angiography were used to study and document the evolution
of nerve head abnormalities. The optic nerve heads were also studied
histopathologically. Except in certain instances of early transient
(relative) filling defects, normal disc fluorescent patterns were
preserved, despite clinically apparent optic nerve head pallor. Sectorial
defects did not persist into the later phases of the angiogram. These
findings may suggest a reduced blood flow, but neither angiographic nor
histopathologic studies detected a reduced vascularity in the atrophic
optic nerve. Pallor of the optic nerve head seems to result from
alterations in the tissue reflectance and translucency following axonal
loss and glial reorganization rather than from a decreased microvascular
bed.
