L
ast weekend’s art
homework was a frustrating
experience for 11-year-old
Tom. He was asked to cut
lots of different coloured snippets
from magazines and arrange the
pieces in shade order to make a
collage colour wheel. Tom is usually
a capable child but, on this occasion,
he was completely stumped. However
long he stared at the pieces of
coloured paper, he just could not work
it out. It was something he would
never be able to do, because Tom is
colour blind.
Colour blindness – or colour
vision deficiency (CVD) as it is more
correctly known – is thought to affect
one in 12 males, and one in 200
females. CVD does not generally
mean that a person sees in black
and white, but rather that he will
not be able to see the full spectrum
of colours, and will be unable to
distinguish the differences between
certain colours and shades. By far
the most common form of CVD,
accounting for 95 per cent of cases,
is red/green colour blindness, where
people may not be able to interpret
colours with either red or green in
their composition. For example, if a
person cannot see red, he also cannot
recognise the red part of purple, so he
will see it as blue, and a red dress will
appear as murky green.
Although the severity of CVD
varies enormously from person to
person, for some people the names
“red”, “orange”, “yellow”, “brown”
and “green” are simply different
names for the same colour. According
to statistics from the campaigning
organisation Colour Blind Awareness,
a person with moderate red/green
colour blindness will probably only
be able to identify around five colours
out of a standard pack of 24 coloured
pencils. Inevitably, this can present
challenges in many areas of life, not
just in the art class.
What causes colour blindness?
A person with normal colour vision
has three sets of light receptor cells,
known as cones, in the retina at the
back of the eye, which are responsive
to red, green and blue light. These
cones then translate the light we see
into the full spectrum of colours. If
a person has CVD, one of the sets of
cones is either faulty or missing. If a
person’s red cones are affected, it is
known as protanomaly or protanopia;
if their green cones are affected,
it is known as deuteranomaly or
Colour blindness is a surprisingly common condition, but what
impact might it have on a child’s life?
Rachel Kenney
finds out.
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December 2013
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