It is rarer for younger people to have difficulty with colour perception and their vision but it is noted that people over the age of seventy have a more rapid decrease in perception. The Smith - Kettlewell Eye Research Institute write that colour discrimination declines with age and that it is the blue- yellow type defects that affects more of the older generation.A research based test was carried out in a sample of random fifty eight to one hundred and two year olds. None of the participants had pre existing colour blindness. The Institute recorded that overall forty percent of the sample had marked abnormal reuslts on one of the two colour vision tests used. A fifth of the 865 failed both of the tests. Confusion with lighter color shades was predominantly the issue in the blue yellow margins.These "blue-yellow" errors are distinct from the "red-green" errors observed in people with inherited color blindness, which affects about eight percent of males and 0.5 percent of females. Although the two tests had different failure rates, they detected similar frequencies of blue-yellow errors.
Measurable deterioration is occurring as we age, but the very subtle discrepancies are likely not inhibiting or even noticed.