COLOUR VISION

Abnormal colour vision increases significantly with ageing, affecting half or more of people in the oldest age groups, according to a
recent study.

While few people younger than 70 have problems with colour vision, the rate increases rapidly through later decades of life, according to research published in Optometry and Vision Science by Marilyn E Schneck PhD, and colleagues of The Smith-Kettlewell Eye Research Institute, San Francisco, US.

“We find the colour discrimination declines with age and that the majority of colour defects among the older population are of the blue-yellow type,” said Dr Schneck.

In the study, researchers administered colour vision tests to a random sample of 865 older adults ranging from 58 to 102 years. The study excluded those with any type of congenital colour-vision defect, with the types and rates of colour vision abnormalities assessed in different
age groups.

Overall, 40 per cent of the participants had abnormal results on one of the two colour vision tests used in the study. Twenty per cent failed both tests. The failure rate was markedly higher in older age groups. Although colour-vision abnormalities were uncommon in people younger than 70, they were present in about 45 per cent of people in their mid-70s, up to 50 per cent of those 85 and older, and nearly two-thirds of those in their mid-90s.

Nearly 80 per cent of the abnormalities involved confusion of the lighter (pastel) shades of blue versus purple and yellow versus green and yellow-green.

The results confirm previous studies showing that colour vision deteriorates measurably with ageing. While most subtle ageing-related colour vision abnormalities are likely to go unnoticed, the researchers note that nearly 20 per cent of older adults failed the easier of the two tests, “designed to only detect defects sufficiently severe to affect performance in daily life.”

“These individuals would have problems carrying out some tasks that rely on colour vision,” said Dr Schneck.

Educate patients

In terms of measures that could be taken to potentially counteract the loss of colour discrimination in elderly patients, Dr Schneck told EuroTimes that it was important to educate patients on the need for enhanced lighting in the home.

“Colour vision declines with lower light levels, so the main thing that can be done is to optimise lighting with bright, non-glaring light. Increasing awareness of the issue is also important,” she said.

She added that improved lighting conditions will also help to reduce the risk of falls which are one of the most common sources of accident in the home for this population group.

“We know that the most common age-related eye diseases such as cataract, glaucoma, age-related macular degeneration and diabetic retinopathy are all associated with blue-yellow colour defects early on. These diseases also affect contrast-sensitivity, a very important aspect of vision that makes it difficult to see the edges of stairs, curbs and so on, which would increase the risk of falls,” she concluded.

Marilyn E Schneck: mes@ski.org