Evolution of human colour vision lights, which appear to be clear. Other colour perception issues include having trouble distinguishing yellows from reds and violet, lavender and purple from blue. In other cases, objects that reflect both red and blue light may appear to just be blue to these individuals. Deuteranopes, who are missing medium wavelength sensitive cones, are similar to protanopes in that they cannot distinguish between colours in the green-yellow-red part of the electromagnetic spectrum. However, deuteranopes do not suffer from dimming issues. For example, purple colors are not seen as being opposite to other colours in the spectrum but instead appear to be
Human eye Exposure-response relations were evaluated by linking incidence rates for each symptom with categories of exposure. Acute incidence rates for nasal, eye, and throat irritation, and coughing and breathlessness were found to be associated with increased exposure levels of both exposure indices. Steeper exposure-response slopes were seen when short term exposure concentrations were used. Results from multivariate logistic regression analysis suggest that current smokers tended to be less sensitive to the exposure to airborne sodium borate dust. Several actions can be taken to prevent eye irritation— In addition, other measures are proper lid hygiene, avoidance of eye rubbing, and proper use