Nutritional optic neuropathies.

Nutritional deficiency may be the cause of a genuine optic neuropathy, sometimes associated with involvement of the peripheral nervous system. Nutritional optic neuropathies are usually bilateral, painless, chronic, insidious and slowly progressive. Most often, they present as a non-specific retrobulbar optic neuropathy. The differential diagnosis with other causes of optic nerve involvement, in particular of toxic origin, may be particularly difficult. Nutritional deficits are often associated with toxic effects from alcohol and tobacco; therefore, the separation of the nutritional and toxic components is often illusory and artificial. The pathophysiological mechanisms involved in nutritional -- and toxic -- optic neuropathies affect biochemical pathways involved in cell energetic production, correction of oxidative stress and quenching of free radicals. The recognition of these mechanisms could provide future therapeutic alternatives. Currently, the treatment is limited to the intensive use of vitamins with variable results in individual cases, and to the implementation of preventive measures, when feasible.