Smoking and lens optical density.

Epidemiological evidence indicates that smoking increases the risk of age-related cataract. No information is currently available, however, on the effects of smoking on the lens prior to cataract development. In this study, we relate smoking behavior to lens optical density (OD) in younger individuals without frank cataract. Fifty three never smokers and 41 current smokers were compared directly. Thirty one past smokers were tested to examine the relationship between years since smoking cessation and lens OD. Lens OD was measured psychophysically by comparing scotopic thresholds obtained at 410 (measuring) and 550 nm (reference). Stimuli were presented in Maxwellian view. The smokers in the sample smoked an average of 17.3 +/- 11.3 cigarettes/day for 20.4 +/- 12 years. No significant differences (other than in fat intake) were found between the smokers and nonsmokers in iris color, dietary patterns, or age. Despite their overall similarity, lens OD was significantly (p = 0.005) higher in the smokers. Moreover, we found a significant dose-response relationship (p = 0.02) between smoking frequency and lens OD. There was also a weak relationship between smoking frequency and lens OD for past smokers (p = 0.06), but no relationship between lens OD and years since smoking cessation. Our data indicate that smoking is directly related to age-related increases in lens OD throughout life and that these increases persist even after smoking cessation.