Smoking reduces colour perception

According to the study, conducted by scientists from the Perception, Neuroscience and Behavior Laboratory in Brazil alongside a co-author from Rutgers University, smokers can experience significant changes in red-green and blue-yellow colour vision due to the consumption of neurotoxic chicals in cigarettes.Additionally, heavy smokers were found to be less capable of discriminating between contrasts and colours when compared to non-smokers. Cigarette smoke consists of numerous compounds that are harmful to health, and it has been linked to a reduction in the thickness of layers in the brain, and to brain lesions, involving areas such as the frontal lobe, which plays a role in voluntary movent and control of thinking, and a decrease in activity in the area of the brain that processes vision, said study co-author Professor Steven Silverstein, director of research at Rutgers University Behavioral Health Care.The researchers recruited 71 participants who had smoked fewer than 15 cigarettes in their lifetime, and 63 people who smoked more than 20 cigarettes per day and were diagnosed with tobacco addiction. The study participants were aged from 25 to 45, and all had normal or corrected-to-normal vision based on measurents using standard visual acuity charts.To determine how the subjects discriminated contrast levels and colours, they were seated 59 inches from a 19-inch cathode-ray tube monitor, which displayed various stimuli. The researchers then monitored both eyes. Previous studies have pointed to long-term smoking as doubling the risk for age-related macular degeneration and as a factor causing lens yellowing and inflammation. 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, Silverstein said.The study did not provide a physiological explanation for the findings, but referenced previous research that donstrated nicotine and smoking affect the vascular syst, resulting in damage to blood vessels and neurons in the retina.The research has been published in the journal Psychiatry Research.