Age-dependent effects of wavelength upon visual performance

Two methods have been used to measure the effects of wavelength of light upon visual perfonnance of subjects over the age of 60. Subjects between the ages of 20 and 35 served as a control group. We used four luminance-matched conditions: white (Tc = 6300 K), blue, green and red (maximum transmission at respectively 450, 550 and 650 om). The first method was a search task in a pseudotext. In addition, the luminance contrast of the text was varied. The second experiment was the measurement of the contrast-sensitivity function for the four colour conditions. No wavelength effects were found in the young age group. Above the age of 60, wavelength effects were found at low contrast in both experiments. The performance and contrast sensitivity were worst with blue light. This effect increased with age. The founded wavelength effects are ascribed to the wavelength-dependent increase of absorption with age.