Optic atrophy refers to degeneration of the optic nerve resulting in vision loss and changes in the appearance of the optic disc. It can be primary, secondary, consecutive, or glaucomatous. Primary optic atrophy is caused by lesions along the visual pathway and results in a chalky white disc. Secondary optic atrophy follows optic nerve swelling and has a dirty grey-white appearance. Consecutive optic atrophy is caused by retinal or choroidal disease and leaves a waxy pallor. Glaucomatous optic atrophy is characterized by deep cupping of the disc. Diagnosis involves imaging and visual field testing while treatment focuses on the underlying cause.