Dichromatic is the adjective used to refer
to deficiencies in colour vision in which those affected can percieve
only two of the three primary colours. Therefore those affected can match
any colour with some particular combination of just two (2) wavelengths
of light, whereas normally-sighted people need three (3) wavelengths of
light in order to acceptably match any colour on the visible spectrum.
People who are dichromatic may be said to have "dichromacy".
They are called dichromats.
There are three forms of dichromacy:
For comparison (in short summary):
- Protanopia
- involves inability to distinguish between colours in the
green-yellow-red section of the spectrum due to lack of
the long-wavelength sensitive retinal cones.
- Deuteranopia
- involves inability to distinguish between colours in the
green-yellow-red section of the spectrum due to lack of
the medium-wavelength sensitive retinal cones.
- Tritanopia
- involves inability to distinguish between the colours
in the blue-yellow section of the spectrum.
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See also more general information about Colour
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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