Colour Blindness is a general term
used to indicate deficiency in colour vision / perception.
That is, those affected do not perceive and distinguish colours in the
same way as the vast majority of the population.
There are many specific conditions resulting in inability to distinguish
certain colours from certain other colours. The term colour blindness
may be applied to any (all) of these but it is usually helpful to use
the most specific term known to be correct and likely to be understood
by the person/audience to whom one is communicating.
Terms used to refer to specific forms of colour blindness, or issues
concerning colour vision, include:
People who are dichromatic
have "dichromacy", are
called "dichromats", and
can match any colour with some mixture of just two (2) wavelengths
of light, whereas normally-sighted people are "trichromats",
meaning that they need three (3) wavelengths of light in order
to acceptably match any colour of light.
The three (3) forms of dichromacy are:
- Protanopia
- inability to distinguish between colours in the green-yellow-red
section of the spectrum due to lack of long-wavelength sensitive
retinal cones.
- Deuteranopia
- inability to distinguish between colours in the green-yellow-red
section of the spectrum due to lack of medium-wavelength
sensitive cones.
- Tritanopia
- inability to distinguish between the colours in the blue-yellow
section of the spectrum.
The term Daltonism
is also used to refer to "red-blindness" and is
sometimes also used more generally (named after British Chemist,
John Dalton 1766-1844).
Consider also unexpected (uncommon) sensations of specific
colours.
Chromatopsia
is the general term referring to abnormal colour vision in
which objects appear to be abnormally/"falsely"
coloured or tinged with a colour not perceived by most people.
Some sources describe this as a form of colour
blindness.
- Chloropsia
("Green Vision") - a specific form of chromatopsia.
- Cyanopsia
("Blue Vision") - a specific form of chromatopsia.
- Xanthopsia
("Yellow Vision") - a specific form of chromatopsia.
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Also compare colour blindness with other similar terms:
night
blindness, day
blindness, snow
blindness and blindness.
More about Ophthalmology: This section includes short definitions
of many diseases, disorders, and conditions of the eyes and visual system.
For definitions of other terms in this category, choose from the list
to the left (but note that this is not a complete/exhaustive list).
Other related pages include the diagram
of the eye, and definitions
of parts of the eye, a description
of the human retina, and definitions
of parts of the retina, and the section of short definitions
of clinical and surgical procedures re. eyes and human visual system.
For further information see also our section of Books
about Ophthalmology. |
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This Section
is about
Diseases
and Disorders of the Eyes and Visual System.
To read about other diseases, disorders, or conditions of the eye and
human visual system, use the links on the left-side of this page.
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