Different conditions affecting ONH are illustrated in this chapter. They include epidemic dropsy, cerebral metachromatic leukodystrophy, Gyrate atrophy, Traumatic optic atrophy, Atrophy with vasculitis, Retinitis pigmentosa, Primary optic atrophy, congenital and acquired Toxoplasma, optic pit, Coloboma, Disc pallor in vascular occlusion, atherosclerosis, AION.