How Advances in Optometry work for the Colorblind.

    Did you know that about 8.5% of the world’s population is color blind with 8% being male and 0.5% being female? That may sound like a small number, but even that calculates to 680 million people worldwide. Color blindness is a recessive disorder that affects how your eyes receive wavelengths of light, which in most cases disrupts the function of red-green receptors in the retina. This can be the difference between a person differentiating two different colors, not being able to see the difference, or not seeing those colors at all. The reason why people are affected is that color blindness is a sex-linked genetic disorder, inherited by parents. Fortunately, modern science has allowed for fascinating treatments for this disorder.

Model of the Human Eye

    There are a few things to understand in order to truly grasp the incredibility of the advances in optical sciences. Embedded within each and every organism's cells lie DNA, the genetic material that codes for every physical characteristic about the organism. Specifically, a section of DNA, the gene, would code for an assigned trait of an organism. Through a process called transcription, a DNA sequence is transcribed on mRNA as it is produced. A few edits are completed on the mRNA to splice out the unnecessary sequences transcribed. The protein is translated from this mRNA in a ribosome. In this case, the cones of the retina are made up of multiple disc-shaped transmembrane proteins. The human eye receives light in the retina. It differentiates the wavelengths of light, or color, with a variety of color receptors, also referred to as cones. The gene that codes for the red-green receptors that are sensitive to red and green light is located on the X-chromosome.

X(right) and Y(left) chromosomes

    A chromosome is made up of 2 strands of double-stranded DNA wrapped around histone proteins for structure. The X-chromosome is one of the 2 sex chromosomes that contain genes that code for traits specific to what biological sex the organism is. Most of the genes on the X chromosome encode proteins that have nothing to do w/ the physical structures associated w/ sex. Females have two X-chromosomes without the Y-chromosome while males have one X-chromosome along with a Y-chromosome. With only one X-chromosome, it is impossible for a male to be a carrier of this disorder, the male either has the disease or does not have it. For females, the possibility of not showing for the trait is more likely, either as carriers of the trait or homozygous dominant which is not having the recessive gene for color blindness at all. The possibility of being color blind depends on your parents' genotype but in all cases, there is a higher chance of being color blind as a male than as a female. This explains the statistic from the first paragraph.

    Now that you know how people inherit this disorder, how exactly does one treat it? For some time, color blind people had the option to wear contact lenses saturated in the color they could not see. This significantly improved the sight of color in some. Although these improved the color perception, they still did not correctly simulate what functional color perception looks like. For some time there was no way to truly do that. That was until a glass researcher, Don McPherson, Ph.D., along with other members of EnChroma invented a pair of glasses that properly display each wavelength of visible light for color blind people. Normally, the cones in the retina have overlapping regions as a way to increase efficiency however when each cone overlaps too much, poor color discrimination occurs. The EnChroma glasses use a filter to cut out these overlapping wavelengths. One can only imagine how long this took to develop, especially since optometry is a fickle and ever-evolving study.

EnChroma's colorblind glasses

    Unfortunately, there are some extreme cases where people are born without color receptors called achromatopsia. This is also a genetic disorder that is linked to the X-chromosome. It is less common and a recessive trait. Sadly, there is no cure or treatment for this even with these special glasses. These glasses utilize the defectivity of the receptors so without cones or completely dysfunctional one's glasses would have nothing to work on.

    Your eyesight is precious. It is almost everything you know and remember. You would not be able to read this article without it. Since this is the case, it is important you treasure everything you see, from shape to color to depth. And if you are color blind, rest assured that there are options and treatments for you that are quite eye-deal.