Leber’s hereditary optic neuropathy (LHON)

Leber hereditary optic neuropathy (LHON) is a hereditary condition causing severe bilateral vision loss with most progressing to a visual acuity of 6/60 (20/200) or worse. It is caused by mutations in the mitochondrial DNA which leads to axonal swelling in the acute stage, and axonal death in the latter stage.

The acute phase of LHON presents with acute, painless loss of central vision in one eye with the second eye typically becoming involved 6-8 weeks later. Clinical signs at presentation include optic disc hyperemia, vascular tortuosity, peripapillary telangiectatic vessels and swelling of the peripapillary RNFL. However, the fundus may appear normal in 20-40% of cases.

As the acute phase subsides (approximately 6 weeks), the disc hyperaemia, peripapillary telangiectasia and oedema resolve. Atrophy of the RNFL can subsequently follow, confined to the papillomacular bundle in most cases.

Visual field test may show central or centrocecal scotomas.

Man PYW, Turnbull DM, Chinnery PF (2002) Leber hereditary optic neuropathyJournal of Medical Genetics 39:162-169.

Meyerson, C., Van Stavern, G., & McClelland, C. (2015). Leber hereditary optic neuropathy: current perspectives. Clinical ophthalmology (Auckland, N.Z.), 9, 1165–1176.