 Eye
Diseases and Conditions 
Color Vision (Color Blindness)
Color
Blindness printable pdf version (70k)
Color vision difficulty is most often hereditary. It is a sex-linked
recessive trait and is usually passed form an affected male via
his daughter to his grandson. It is estimated that 1 of 12 boys
and 1 of 200 girls have the problem. This deficiency may also be
acquired through injury or disease, but this is less common. There
are various degrees of color vision impairment. Color vision deficiency
does not usually interfere with visual acuity and correction of
this deficiency is limited at present. Educational referral is recommended
if the color deficiency interferes with the child’s ability
to use the educational materials in his/her classroom.
Color deficiency is defined as the absence of or defect in the
perception of colors. The most frequently used class of color deficiency
is based on the perception of red, green and blue (termed the 1st,
2nd and 3rd color factors, respectively). If there is a defect in
the perception of one of these colors, a color will be perceived
as if it were composed only of the other two colors. Based on the
color or colors for which there is defective perception, a person
may suffer from red, green or blue deficiency.
People who have such deficiencies cannot distinguish between certain
colors or shades of colors. The most common deficiency is red-green.
And since most road, marine and air-borne traffic positions use
these colors for signaling, knowledge of a color deficiency is important.
Color deficiency in which all colors are perceived as gray is termed
monochromasia.
Colored plate help determine a person’s ability to perceive
color. Persons with normal color vision will see geometric shapes.
Those with a color deficiency will see a different shape or none
at all. Mild to moderate color deficiency is seldom a handicap.
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