Dark Adaptation and Recovery from Light Adaptation: Smokers versus Nonsmokers

摘要

Since the published data concerning the effects of smoking on visual sensitivity at night are inconsistent, a new study was initiated to investigate this question. Thirty Army aviators between the ages of 19 and 39 volunteered to participate in this study. Of these subjects, 15 smoked and 15 were non-smokers. Each subject was seated in a light-controlled room and exposed to a standardized bright light for 5 minutes. Immediately after the bright light was extinguished, the subject's visual sensitivity was tested by gradually increasing the intensity of a test light until the subject could see it. This was continued over a period of 35 minutes by which time the subjects had reached their maximum light sensitivity. Each subject then wore a pair of AN/PVS-5 Night Vision Goggles for 5 minutes after which his visual sensitivity again was tested for 20 minutes. The data do not show any differences in visual sensitivity between aviators who smoke and those who do not smoke. Blood samples were analyzed to compare serum levels of nicotine, cotinine and carboxyhemoglobin with the visual data. Again, no correlation exists between sensitivity and blood measures related to smoking. Aviators who smoke reach the same level of sensitivity to light as non-smokers and they do so in the same amount of time. Visual recovery after wearing the Night Vision Goggles also followed the same time course regardless of smoking history.