The Not So Colorless World Of Color Blindness

Color blindness as a disability is commonly known. Being color blind myself and having faced a few problems in even applying for the armed forces, color blindness as anything else, but a disability never occurred to me. However, scientific evidence now shows that color blindness can actually be useful in some cases.

We in our retina have different cells for detecting different kinds of light. There are rods, that are active in low light and there are cones, which are active in bright light. Different types of cone cells detect different wavelengths of light and hence help us distinguish between different colors. Color blindness occurs due to a lack of these cone cells on the retina. It varies in degrees of acuteness, and is mostly of genetic inheritance. Besides that, retinal damage, brain damage, and exposure to UV rays may also cause colorblindness.

The genetic mode of transmission of the cone cells is on the X chromosome. Hence color blindness is more common in males (XY) than in females (XX) as females have 2 X chromosomes and hence a greater probability of inheriting a healthy pair of genesdefine.

A common test for color blindness comes in the Ishihara color test. This is a series of pictures as combinations of colored dots with hidden numerals in them. The healthy vision sees a different numeral and different types of color blind people would see a different numeral or none at all. One can have a look and test their color distinguishing capabilities at http://www.toledo-bend.com/colorblind/Ishihara.html.

As an answer to a general misconception, a color blind individual does not see his world as black and white. There are a few closely spaced hues that are generally seen as one. If one is not totally color blind, which is quite rare, they usually have one of these 2 clinical defects:
1. Red green defect
This is seen mostly in males due to gene placement on the X chromosome and is hence gender-linked. There is difficulty or in acute cases a disability to distinguish between certain hues of red, green and yellow.
2. Blue yellow defect
This is not gender-based and is seen equally in both males and females. The green and red lights are perceived separately, but there is difficulty in rendering of different shades of blues and violet.

The common color blindness that we may encounter is not as such a disability. One is not confused at the traffic lights nor does one see the trees red and the sky yellow. In fact, its seen that color blind people are more apt at looking through natural camouflages and also see better in dim light.

So, if the fact that my brother has got a healthy set of genes from my mother while I got the mutated ones disturbs me, the fact that I can find a green ball lost in the grass in the dark while he can’t, does offer some consolation!