Is my child colour blind?

What to do when your child can’t distinguish the colours that you see and talk about.

When Daniell Ng was in nursery school, he would use green to fill the faces and skin of people on his colouring sheets.

Recalls Daniell’s mother, homemaker Chuah Phei Sei, 40, “Initially, I thought he was just being mischievous, colouring their faces green for fun! Even when he described a green-coloured bus as orangey-yellow, I didn’t think much of it. I thought that it was because he was not familiar with colours.”

It was only later, during a trial class at a brain development centre, that she realised that her son wasn’t able to follow a sample card to arrange certain colour cubes. An eye doctor subsequently diagnosed Daniell with colour vision deficiency.

Colour blindness or colour vision deficiency (CVD) is the inability or reduced ability to see colours, or to perceive obvious differences between mixed colours. In Singapore, this condition affects 5.3 per cent of boys and 0.2 per cent of girls.

“Despite having some difficulty differentiating colours, individuals with CVD have good eyesight. Very few people are completely colour blind (achromatopsia), which means they have no colour perception at all. They see the world as white, black and grey. This is associated with severe visual impairment,” explains Dr Grace Wu, a consultant in the Paediatric Ophthalmology and Strabismus Department, Singapore National Eye Centre & KK Eye Centre, KK Women’s & Children’s Hospital.

“Colour blindness or colour vision deficiency (CVD) is the inability or reduced ability to see colours, or to perceive obvious differences between mixed colours... Very few people are completely colour blind.”

Types of Colour Blindness

According to Dr Wu, most colour blindness is hereditary in nature. It is caused by a defect in the gene containing instructions to make photo pigments in the cones for seeing colours.

* The most common form of colour blindness in children is Red–Green due to loss or abnormal function of red cones photo pigments or green cones photo pigments in the eyes. If the red cone photo pigments are abnormal, red, orange, yellow will appear greener and less bright. If the red photo pigments are absent, red will appear black. Likewise, if the green cone photo pigments are abnormal, it may be difficult to tell blue from violet ― the most common form of red green colour blindness.  This condition is very mild and does not interfere with daily living.

* Blue-Yellow colour blindness is rarer. The blue pigments are missing or have limited functions. Blue may appear green and yellow looks more like violet to these affected individuals.

* Complete colour blindness, in which the child sees no colours at all, is extremely rare and associated with severe visual impairment.

In Daniell’s case, he is unable to differentiate certain shades of blue-purple and green-pink-yellow.