Green colour weakness or blindness is most common, followed
by red colour weakness or blindness. It is important to remember
that not all cases of colour blindness are congenital as there
are some diseases acquired later in life, like diabetic eye
disease, glaucoma, retinal or optic nerve disease which may
disrupt colour vision.
The Importance Of Colour Vision Testing
It is important to know if you are colour blind. Colour is
often used as an aid to teaching in pre-primary and primary
schools. Children who have difficulty distinguishing between
colours may be misdiagnosed as having learning difficulties
unless it is known beforehand that they have a colour vision
defect. Knowing the existence of a colour vision defect early
can thus help prevent communication problems in school and
in later adult life.
Schoolchildren with colour vision defect should think over
carefully before choosing study subjects where colour discrimination
is important. Art and chemistry are two examples of such subjects.
Consider colour deficiencies when making career decision.
This is because many occupations demand good colour discrimination.
Defective colour vision is a handicap in some pharmacy and
chemistry jobs. Colour is often used to convey important information
such as in traffic and navigational lights and colour coding
of electrical wires.
How We See Colour
Our eyes are capable of differentiating an infinite array
of colours. Yet, would you believe that all our colour sensations
are actually derived from varying stimulation of only three
types of colour receptors, namely red, green and blue?
These receptors, called cones, are found solely in the centre
part of the retina in an area called the macula. The retina
is the nerve layer lining the back of the eye, much like the
film in a camera.
The colours red, green and blue are also known as the primary
colours. A suitable mixture of these three colours can produce
any colour including white!
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