Eyes & Vision

Optic Neuritis

Optic neuritis is inflammation of the optic nerve causing subacute visual loss, impaired colour vision, a relative afferent pupillary defect and often pain on eye movement; it needs urgent eye assessment and may be the first presentation of multiple sclerosis or antibody-mediated disease.

Definition

Optic neuritis is inflammation of the optic nerve causing optic-nerve dysfunction, usually with subacute visual loss, impaired colour vision, a relative afferent pupillary defect and often pain on eye movement. It may be associated with multiple sclerosis, NMOSD, MOG-antibody disease or another inflammatory, infectious, ischaemic, compressive or infiltrative disorder.

First principles

Optic nerve dysfunction produces a functional pattern

Inflammation or demyelination interrupts transmission from the retina to the visual cortex. The affected eye therefore has reduced acuity, colour desaturation and a visual-field defect; reduced afferent input produces a relative afferent pupillary defect when the other eye is better.

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