This document discusses optic neuritis, papilledema, and optic atrophy. It defines each condition, describes their signs and symptoms, classification, etiology, investigations, treatment and prognosis. Optic neuritis is inflammation of the optic nerve that can be caused by demyelination, infection or autoimmunity. Papilledema is bilateral swelling of the optic disc due to increased intracranial pressure. Optic atrophy is degeneration of the optic nerve fibers leading to pallor of the optic disc. The document provides detailed information and images to help understand and differentiate between these three important optic nerve conditions.