Color Vision Problems as We Age
Abnormal color vision increases significantly with aging and affects 50% or more of people in the oldest age groups, according to a study done at The Smith-Kettlewell Eye Research Institute in San Francisco and published in the journal Optometry and Vision Science.
A release form the publisher reports that Marilyn E. Schneck, PhD and colleagues explained that although few people younger than 70 have problems with color vision, the rate increases rapidly through later decades of life. The team wrote: "We find the color discrimination declines with age and that the majority of color defects among the older population are of the blue-yellow type."
The researchers administered color vision tests to a random sample of 865 older adults ranging in age from 58 to 102. The study excluded subjects with any type of congenital color-vision defect, commonly called color blindness. The types and rates of color vision abnormalities were assessed in different age groups.
Overall, 40% of the participants had abnormal results on one of the two color vision tests used in the study while 20% failed both tests. However, the failure rate was markedly higher in older age groups. About 45% of people in their mid-70s, up to 50% of those 85 and older, and nearly two-thirds of those in their mid-90s had color vision problems.
Nearly 80% of the abnormalities involved confusion of the pastel shades of blue versus purple and yellow versus green and yellow-green. These "blue-yellow" errors are distinct from the "red-green" errors observed in people with inherited color blindness, which affects about 8% of males and 0.5% of females. Although the two tests had different failure rates, they detected similar frequencies of blue-yellow errors.
The results confirm previous studies showing that color vision "deteriorates measurably" with aging. Most subtle aging-related color vision abnormalities are likely to go unnoticed, the researchers suggest.
However, they note that nearly 20% of older adults failed the easier of the two tests, "designed to only detect defects sufficiently severe to affect performance in daily life." Dr. Schneck and colleagues wrote: "These individuals would have problems carrying out some tasks that rely on color vision."
The researchers discuss factors that may contribute to changes in color vision with aging, and to blue-yellow defects in particular. These may include reduced pupil size, admitting less light into the eye; increased yellowing of the lens inside the eye; and changes in the sensitivity of the vision pathways. All of these are known changes with age to the human eye.
Increased rates of eye diseases are another potentially important contributor. The team wrote: "The most common age-related eye diseases (glaucoma, age-related macular degeneration, and diabetic eye disease) all produce blue-yellow color vision anomalies, at least in the preclinical or early stages."