Tobacco optic neuropathy (TON) - the historical and present concept of the disease.

This article reviews the historical and current concepts of 'tobacco optic neuropathy' (TON) a rare disorder of optic nerve function related to the toxic effects of an unidentified constituent of tobacco. It is considered to be an entity distinct from that often described as 'tobacco-alcohol amblyopia', a disorder better described as a nutritional optic neuropathy. It is suggested that 'tobacco-alcohol amblyopia' is an inappropriate term, because the condition to which it refers is not an amblyopia, and there is little evidence to implicate a toxic effect of either tobacco or alcohol in the pathogenesis of that disorder.