What is Leber hereditary optic neuropathy?
Leber hereditary optic neuropathy (LHON), or sudden vision loss, is an inherited form of vision loss. LHON is a mitochondrial disease, which means it is only inherited through the mother. Individuals who have lost their central vision are referred to as “affected.” Individuals who carry one of the mitochondrial mutations but do not experience vision loss are referred to as “carriers.”
What causes Leber hereditary optic neuropathy?
LHON is a genetic condition caused by a mutation in the mitochondrial DNA. Vision loss occurs because the cells in the optic nerve die. The optic nerve relays visual information from the eyes to the brain and once these cells die the optic nerve can no longer do its job effectively.
What are the symptoms of Leber hereditary optic neuropathy?
LHON typically starts with painless, visual blurring that affects the central visual field in one eye. The other eye develops similar symptoms on an average of two to three months later. In about 25% of cases, both eyes develop vision loss simultaneously. Usually vision loss is the only symptom of LHON. The onset of symptoms occurs between the ages of 15 and 35 years in most cases. However, ages of onset between 2 and 87 years have been reported.