Acquired Color Vision Defects in Chronic Heavy Smoking

Nicotine, a psychoactive compound of cigarette, is an alkaloid that binds and activates nicotinic acetylcholine receptors on the retina and lateral geniculate nucleus, being able to affect visual spatial processing. Losses in color vision have been associated with chronic exposure to cigarette. Since not all tests of color discrimination investigation are designed to detect acquired losses, the Lanthony D15 desaturated (D15d) panel presents itself as an essential and reliable tool for this identification. The D15 is a simple 15 cap color arrangement test, designed to identify mild acquired color losses and can be quickly administered under standard conditions. This test generally describes loss of color discrimination, affecting both the blue-yellow axis and the red-green axis. We tested 20 non-smokers (10 males) and 20 smokers (10 males). All subjects were free of any neurological disorder, identifiable ocular disease and had normal acuity. No abnormalities were detected in the fundoscopic examination. Color discrimination was evaluated with the Lanthony D15d test. Results from both groups were compared using the Mann-Whitney U Test. The number of errors in the D15d was higher for smokers when compared to non-smokers. These results suggest that not only chronic exposure to cigarette compounds but also smoking habit affected spatial vision. This highlights the importance of understanding diffuse effects of smoking compounds on color processing.