Smoking more than 20 cigarettes a day may affect colour vision

New research indicates the impact of heavy smoking on a person’s colour vision

Writing in Psychiatry Research, scientists have reported on their study of 71 people who smoked fewer than 15 cigarettes in their lives and 63 smokers.

The smokers featured in the research smoked more than 20 cigarettes a day were diagnosed with tobacco addiction and had not made attempts to stop smoking.

All participants were aged between the ages of 25 and 45 and had normal vision as measured by standard acuity charts.

The researchers tested how study participants discriminated between differences in colour and contrast and it was found that the smokers had significant changes in their red-green and blue-yellow colour vision, with a reduced ability to differentiate between contrast and colours when compared to non-smokers.

Co-author, Steven Silverstein, director of research at Rutgers University Behavioral Health Care in the US, highlighted that previous research has connected long-term smoking with doubling the risk for age-related macular degeneration and as a factor in the yellowing and inflammation of the lens.

Smoking harms blood vessels and neurons in retina

‘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,’ he commented.

The research doesn’t give a physiological explanation for the results, but Silverstein says that since nicotine and smoking harm the vascular system, the findings suggest they also damage blood vessels and neurons in the retina.

The findings also suggest that research into visual processing impairments in other groups of people, such as those with schizophrenia who often smoke heavily, should take into account their smoking rate or independently examine smokers versus non-smokers.

The Centers for Disease Control and Prevention estimates that 34.3 million adults in the United States currently smoke cigarettes and that more than 16 million live with a smoking-related disease, many of which affect the cardiovascular system.