Smoking and optic neuritis.

The effect of smoking on the recovery of visual function after an attack of optic neuritis has been assessed in 125 patients. Heavy smokers were found to have a higher incidence of red/green colour vision defects than non-smokers. The possible implications of this finding are discussed. One patient is described in whom smoking caused transient blurring of vision. The effects of nicotine on the central nervous system are reviewed, and a pathophysiological mechanism suggested for this phenomenon.