According to Prevent Blindness America, 8% of men and less than 1% of women are color deficient. We use the words ‘color blind’ to describe these individuals though they are not completely blind to colors. In fact they see most colors the same way others would. They are, however, less sensitive to some wavelengths, most commonly red and green and may confuse those colors. A smaller population would have trouble distinguishing yellows and blues.
An example of how Red/Green deficient vision may appear is shown.
Red/Green deficiency is the most common inherited type of color blindness and caused by a recessive X-linked gene. This results in the gene being expressed more commonly in boys since mothers who carry the gene will definitely pass on the deficiency to their sons but can only pass it on to their daughters if the father is also color deficient. The daughters, however, will be carriers of the gene.
There are different severities of color blindness, from seeing only shades of gray (a rare condition called monochromatism) to a mild washing out of certain colors due to an inability of some cells to respond to certain wavelengths. Most people are born with this condition and may not realize it until someone tells them the color they see is not what they think.
If however, perception of color seems to be changing, it is very important to get your eyes tested. Certain disease from cataracts to medication side effects to neurological issues can lead to color vision loss. Early testing can be critical.
Treating color vision is limited to a wearing tinted lens in one eye – either in contacts or in glasses. This will allow the brain to receive differing information between the hues seen each eye and thereby detect variations in the different colors. Gene therapy also holds some potential for the future though much research is still needed.
Here are a few color plates similar to the ones I show in the exam room when screening for color deficiency. What do you see?
references: Allaboutvision.com (research and images); colorvisiontesting.com (research and images)
