Gene Therapy May Someday Correct Color Blindness.

20 Nov

Color Blindness is a common inherited gene defect that primarily affects boys according to Dr. John Henahan at Spectrum Eyecare in Peachtree City.  It is Color Blindness test sample platedetected during a regular eye exam at your eye doctor or pediatrician reports Dr. Henahan.  Historically, there have been no treatments or cure for this condition.  The primary symptom is that it is difficult to tell the difference between red and green. (That is why  red is always on top and green is always on the bottom on traffic lights.) If you want to test your color vision online, go to

Causes of Color Blindness

Color blindness is the most common single gene disorder in humans affecting nearly 13% of men.  The most common cause of color blindness is a chromosomal defect that results in the eye having only two color receptors instead of three.  This results in the classic red-green color blindness that is seen in boys.  (The gene defect is carried on the X chromosome, and since girls have two X chromosomes, it is much more rare for girls to have the defect on both X chromosomes, hence they have normal color vision. Boys have only one X chromosome.) There are other genetic types of color blindness but they are so rare that they are infrequently seen in practice.

Other causes of color blindness can come from diseases of the eye.  They will typically effect each eye differently and can cause problems with differentiating between blue and yellow as well as red and green.

 Emerging Gene Therapy

On the front of its Personal Journal section, the Wall Street Journal (11/6, D1, Beck, Subscription Publication) reports in “Health Journal” that gene therapy may someday help make colorblind people see the colors red and green. In 2009, vision researchers at the University of Washington were able to restore red-green color vision to squirrel monkeys by injecting a missing gene into a virus inserted into the animals’ retinas. The animals still can see the colors red and green today.

What is it like to be Color Blind?

The term colorblind is actually a misnomer.  It is not a gray scale world, rather you can see colors they just look different.  For example, a person with the common red-green color blindness does not see the red in purple, only the blue.  Since red and green combine to make brown, those who are color blind confuse those three colors. Depending upon the severity of the defect, some people are considered only red-green color deficient, because they can easily see pure, strong colors, but not muted colors.

There’s an App for that!

Now, new tools, apps, contact lenses and special eyeglasses can help people with colorblindness recognize certain colors. DanKam is an iPhone and Android app wherein the user looks at objects through the camera and the app converts all the red and greens to pure basic versions that are easier to recognize. HueVue is another app that helps identify colors through the phone camera. HueVue and Colorblind Helper can also help with harmonizing colors (ie when choosing clothing).  Some video games are adding “colorblind mode” to help color deficient players enjoy the game as well.

As technology advances, we may ultimately see a cure for the most common forms of color blindness but in the meantime, technology can enhance the lives of the millions of people around the world suffering from color deficiency.

Dr. John Henahan is a fellowship trained doctor of optometry practicing and living right here in Peachtree City with his wife and two sons.  You may call his office at (770) 487-0667 or visit him on the web at

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