Effect of Cigarette Smoking on the Critical Flicker Frequency of Heavy and Light Smokers

In order to evaluate the effects of smoking on CFF, heavy and light smoker thresholds were determined 5 min. and 1 min. before, and then 1, 5, 10, and 15 min. after 10 inhalations of a cigarette. Although both groups of smokers showed a significant elevation in CFF immediately after smoking, the light smokers' CFF gradually returned to pre-smoking levels, while the heavy smokers' CFF fell below and then rose above the pre-smoking level.