Color Vision and Tests Used to Assess Color Vision

Abstract

Testing for abnormalities other than strabismus is often included in the expanded role of the orthoptist. One such area is testing for color vision.

Color vision results from the stimulation and absorption of wavelengths of light by three types of photosensitive pigments within the cones of the retina. This action produces color signals which are transmitted by three related neural pathways and are interpreted within the visual system. This is known as the Color Vision Mechanism. This paper includes a more comprehensive explanation of the Mechanism. It also contains the classification and an explanation of the various types of color deficiencies, i.e.: the types of anomalous trichromacy, the types of dichromacy and monochromacy.

Various color vision tests are discussed relating to their design and capability of identifying and analyzing color defects.

• primary colors
• color vision mechanism
• color vision deficiencies
• trichromacy
• dichromacy
• monochromacy
• protanope
• deuteranope
• pseudoisochromatic plates