Leber Hereditary Optic Neuropathy (LHON)

Leber hereditary optic neuropathy is an inherited condition that causes sudden, painless loss of central vision due to damage of the optic nerve, usually in young adults.

Common symptoms

Rapid blurring or loss of central vision in one eye, followed weeks or months later by similar loss in the other eye, often with poor colour vision.

Description

LHON is caused by changes in mitochondrial DNA, passed down through the maternal line. These changes affect how the cells of the optic nerve produce energy, leading to their breakdown.

The condition most often appears in men in their teens, twenties, or thirties. Vision loss is typically painless and starts in one eye, with the second eye usually affected within a few months. Although peripheral vision is generally preserved, central vision is often severely reduced.

There is currently no reliable cure, but some medicines and emerging gene therapies are being studied, and some people experience partial recovery over time. Avoiding smoking and heavy alcohol use is strongly recommended for anyone known to carry an LHON mutation.