Furthermore, those who smoked the most actually had the greatest risk. Men who smoked a pack or more a day were 2 to 3 times more vulnerable to developing Macular Degeneration. Karen Cruickshanks, associate professor of ophthalmology and visual sciences found that in a study of 4,753 adults age 48 to 97 smokers had a 70 percent higher risk of hearing loss than nonsmokers. A continuing study is needed to determine if an exact cause-effect relationship exists. There are several factors that make investigation of the effects of smoking on night vision difficult.
Contradictions still exist in the published studies.
Night vision is, in itself, a complex physiological process. Visual function at night encompasses many parameters, e.g., scotopic dark adaptation, mesopic vision, contrast sensitivity, visual discrimination of moving targets, peripheral retinal sensitivity, glare recovery, and dark focus. One well-done study found that temporary abstinence from smoking could sharply improve the night vision of smokers. Several studies found that smokers were more likely to have automobile accidents than nonsmokers were. Another study reported that, among people who had automobile accidents, smokers were more than two times as likely to have their accidents at night.