And when a patient with LHON or toxic/nutritional optic neuropathy has a hypertensive crisis as a possible complication of the disease process, nitroprusside (trade name: Nipride) should not be used, due to increased risk of optic nerve ischemia in response to this anti-hypertensive.Idebenone  has been shown in a small placebo-controlled trial to have modest benefit in about half of patients. People most likely to respond best were those treated early in onset. α-Tocotrienol-quinone, a vitamin E metabolite, has had some success in small open-label trials in reversing early onset vision loss.Various treatment approaches have had early trials or been proposed, but so far none with convincing evidence of usefulness or safety for treatment or prevention, including brimonidine, minocycline,   curcumin, glutathione, near infrared light treatment, and viral vector techniques. "Three person in vitro fertilization" is a proof-of-concept research technique for preventing mitochondrial disease in developing human fetuses. So far, viable macaque monkeys have been produced. But ethical and knowledge hurdles remain before use of the technique in humans is established. Idebenone
Idebenone is a short-chain benzoquinone that interacts with the mitochondrial electron transport chain to enhance cellular respiration. When used in people with LHON, it is believed to allow electrons to bypass the dysfunctional complex I. Successful treatment with idebenone was initially reported in a small number of patients.Two large-scale studies have demonstrated the benefits of idebenone. The Rescue of Hereditary Optic Disease Outpatient Study (RHODOS) evaluated the effects of idebenone in 85 patients with LHON who had lost vision within the prior five years.
While the balance between risks and benefits of HRT remains controversial, the decision to start HRT requires an individualized approach based on the patients context. While not applicable for all post-menopausal women, prophylactic (and therapeutic) HRT should be considered in all female carriers of a known LHON mutation given the substantial risk of vision loss associated with menopause. Epidemiology
In Northern European populations about one in 9,000 people carries one of the three primary LHON mutations. There is a prevalence of between 1:30,000 to 1:50,000 in Europe. The LHON ND4 G11778A mutation is the primary mutation in most of the world, with 70% of Northern European cases and 90% of Asian cases. Due to a Founder effect, the LHON ND6 T14484C mutation accounts for 86% of LHON cases in Quebec, Canada.More than 50% of males with a mutation and more than 85% of females with a mutation never experience vision loss or related medical problems. The particular mutation type may predict the likelihood of penetrance, severity of illness and probability of vision recovery in the affected. As a rule of thumb, a woman who harbors a homoplasmic primary LHON mutation has a ~40% risk of having an affected son and a ~10% risk of having an affected daughter.Additional factors may determine whether a person develops the signs and symptoms of this disorder. Environmental factors such as smoking and alcohol use may be involved, though studies of these factors have produced conflicting results.