Abstract
Involvement of the optic nerve is almost invariable in patients with multiple sclerosis but acute optic neuritis occurs in less than half of the cases. Latent and chronic optic neuritis are the commonest manifestations. Investigation o f patients with normal visual acuity often reveals evidence of disease and is useful in diagnosis. A clinical classification of optic neuritis is presented. The pathological findings are reviewed and retinal histology is illustrated. Correlation of clinical findings with electrophysiological and psychophysical testing is discussed.