True colours are in the brain of the beholder

Pictures of brain waves that reveal our ability to see colour could provide a new objective way to diagnose and monitor diseases that affect human colour perception.

The research finding by a Universiy of New South Wales PhD student, Ms Mei Ying Boon, has earned her a nomination in this year's Fresh Science Awards.

"Eye diseases such as glaucoma can alter people's ability to accurately see colour," says Ms Boon. "Therefore, studying brain activity could be a useful way to diagnose and monitor diseases and conditions that affect colour vision pathways in the brain."

Ms Boon and her UNSW colleagues measured the brain waves of 22 adult volunteers while the volunteers viewed computer patterns composed of two different shades. The two colours ranged from very different (red and green) to very similar. If the viewer couldn't distinguish the colours, then the pattern was invisible to them.

When the volunteers could see the pattern, their brain waves included a distinctively patterned wave. The researchers measured this signal three different ways and found it could be used to reveal the finest colour discriminations that individuals can make. The result: a potential visual health test.

"People's natural ability to make fine distinctions between colours varies in the population," says Ms Boon who published her findings in Vision Science with her UNSW co-authors, Dr Catherine Suttle and Associate Professor Bruce Henry.

"For example, we've all met people who are unaware that they mix up colours, or wear colours that clash. For most of us, this isn't a big deal but for those with poor colour discrimination it can make apparently simple tasks difficult. For example, our ability to see colours affects our ability to carry out daily tasks such as food preparation (which is the ripe tomato?) and interpret signals like traffic lights," says Ms Boon.

"More seriously, poor colour vision can be a serious impediment to safety when working in some occupations, such as fire-fighting and electrical wiring. The ability to test objectively people's natural perception of fine colour discrimination could provide them with valuable information about their natural ability," says Ms Boon.