Color blindness is a genetically-linked condition in which the affected person perceives color differently from most other people. The gene associated with color blindness is found on the X chromosome. Those with color blindness, most often males, are not aware of the differences between some colors. Some become aware of the problem when they are very young while others struggle for years not knowing why.
There are three main types of color blindness. Red-Green color blindness is the most common and is the result of low functioning red or green photoreceptors in the eyes. Red, orange, and yellow may appear as green, black, or brownish yellow. The color green may appear as yellow, red, or beige.
Less common blue-yellow color blindness is the result of low functioning blue photoreceptors. Blue may appear as green, and yellow may be seen as violet or grey.
Complete color blindness is rare but does occur. The person who is completely color blind sees a world in black, white, and shades of gray. They may also be near sighted, have uncontrollable eye movements, or be sensitive to bright light.
There are tests available that allow eye care professionals to diagnose specific types of color blindness. The Ishihara Color Test tests for red-green color blindness. It involves a series of colored circles in different colors and sizes. Within the circle are dots that form pictures easily seen by those with normal color vision but difficult to those with red-green color blindness. The Cambridge Color Test is similar to this but is displayed on a computer screen.
Another test uses an anomaloscope. Light from two sources must be matched by color. A circle with two halves, one yellow and the other a combination of red and green, is viewed through an eye piece. The person is asked to adjust the brightness until both halves are the same brightness and color.
The Farnsworth-Munsell 100 Hue Test uses blocks or pegs in varying shades of the same color. The person taking the test is asked to arrange them in order according to hue. This test measures the ability to detect slight changes in color. This test is used by many industries as well as the U.S. military.
Although there is no cure for color blindness, special lenses are available to help people with red-green color blindness differentiate colors. Apps have been developed for iPhones and iPads which aid in identify colors. Pictures can be taken of objects and colors can be identified where the screen is tapped. This would be very helpful when matching clothes or shopping for fruits,vegetables, paints, etc.
Color blindness can make life challenging for those affected, but hope can be found once the problem is identified. The earlier color blindness is diagnosed, the earlier help can be started. Parents should be watchful for signs of color blindness in their children especially if it is present in the mother's side of the family. Boys are most likely to be color blind.