Toxic/nutritional optic neuropathy typically presents with ____________ pallor.

• A. Global pallor
• B. Temporal pallor
• C. Frontal pallor
• D. Nasal pallor

Answer: (B)

Toxic and nutritional optic neuropathies preferentially injure the central retinal fibers that form the papillomacular bundle. These small, mitochondria-rich fibers are most vulnerable, so early damage affects central vision and the nerve fibers delivering that region. On the optic disc, this manifests as pallor greatest toward the temporal side because the papillomacular bundle runs along the temporal aspect of the optic nerve head. So the classic finding is temporal pallor. As the disease progresses, pallor can become more generalized, but the initial and characteristic pattern is temporal. Global pallor would suggest widespread optic atrophy from other causes, not the focal involvement typical of these neuropathies.