New research suggests that smoking more than 20 cigarettes a day may damage a person’s vision and disrupt their ability to see colors.
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In a study comparing smokers and non-smokers, Dr. Steven Silverstein and colleagues from Rutgers University found that smokers could not differentiate between colors as well as non-smokers could and were less able to perceive contrast and shading.
For the study, the team compared 71 participants who had smoked fewer than 15 cigarettes across their whole lifetimes, with 63 people who smoked more than 20 cigarettes a day. The participants were all in good health, had normal or corrected vision and were aged between 25 and 45 years.
The participants were assessed for how well they could discriminate between colors and subtle changes in shading, while they sat about 60 inches away from of monitor that was displaying visual stimuli.
As reported in the journal Psychiatry Research, the team found that the smokers had a reduced ability to differentiate between colors and contrast, compared with the non-smokers and also had significant changes in their red-green and blue-yellow color vision. The researchers suggest that this could be linked to the smokers’ exposure to neurotoxic chemicals found in cigarettes.
Silverstein says studies have previously linked cigarette smoking to brain lesions and an increased risk of conditions such as age-related macular degeneration (AMD), lens inflammation and retinal ischemia. However, few studies have linked smoking to impaired color vision.
Although the current research does not provide a clear explanation for the findings, Silverstein believes that neurotoxic chemicals present in cigarettes could be causing damage to blood vessels and nerves in the eyes.
Our results indicate that excessive use of cigarettes, or chronic exposure to their compounds, affects visual discrimination, supporting the existence of overall deficits in visual processing with tobacco addiction."
Dr. Steven Silverstein, Lead Author