Leber hereditary optic neuropathy

Leber hereditary optic neuropathy is a genetic mitochondrial condition causing sudden, painless vision loss, typically affecting young adult men, due to damage to the optic nerve. It usually starts in one eye before affecting the other within weeks to months.

It's caused by mutations in mitochondrial DNA that impair energy production in the cells of the optic nerve, making them particularly vulnerable to damage. It's inherited exclusively through the maternal line, since mitochondrial DNA is passed only from mother to child.

The main symptom is painless, progressive blurring or loss of central vision, usually starting in one eye and often affecting the other within weeks to months. Colour vision is also frequently affected.

It causes significant, often permanent visual impairment but doesn't typically affect general health or lifespan. Not everyone who carries the genetic mutation develops symptoms, and the reasons for this variable penetrance aren't fully understood.

Yes, it's caused by mitochondrial DNA mutations passed down exclusively from mothers to their children, though not all children who inherit the mutation will develop symptoms. Men are affected far more often than women who carry the same mutation, for reasons not fully understood.

A specific medication (idebenone) is licensed for treating this condition and may help some patients recover some vision, particularly when started relatively early after symptom onset. Supportive low-vision services are also important for managing the visual impairment.

Diagnosis involves detailed eye examination, specialised imaging of the optic nerve and retina, and genetic testing to confirm the specific mitochondrial mutation. Family history assessment, particularly through the maternal line, also supports the diagnosis.

Some patients treated with idebenone see meaningful improvement in vision, though outcomes vary and not everyone experiences significant recovery. Your ophthalmologist will discuss realistic expectations based on your specific situation and how soon after symptom onset treatment begins.

This condition specifically causes painless, progressive central vision loss typically in young men with a family history through the maternal line, distinguishing it from other causes of sudden vision loss like optic neuritis, which is often painful and more common in women, or stroke-related vision loss. Genetic testing confirms the specific diagnosis.

Sudden, painless vision loss should be assessed urgently, ideally within days, since early treatment may improve outcomes. Private ophthalmology consultations for urgent vision loss can often be arranged very quickly, sometimes within a few days, but any sudden vision change should prompt immediate medical assessment rather than waiting.