Introduction
Color blindness, or commonly referred to as color deficiency occurs when someone is unable to distinguish between colors in a normal way. Precisely, one can see but cannot tell the difference between primary colors, red green and blue. The eye structure is composed of cones and rods. The latter perceives the light of high intensity while the former perceives low light levels. There are three types of cones that perceive the abovementioned primary colors. When one of the cone receptors is nonfunctional, detects an inappropriate color or is nonfunctional, the brain cannot determine the correct input from the eye and thus is unable to register the correct color (American Academy of Ophthalmology). Thus, one qualifies to be colorblind.
Symptoms of the disease
The symptoms of this genetic complication can be determined at an early stage by a child’s parents. However, when the symptoms are slight, it takes a longer time for the parents to understand this complication. The common symptoms include the inability to see tones or shades of the same color (National Eye Institute, 2016). In this case, the affected individual perceives different tones as a similar color. Additionally, the people affected experience difficulties when distinguishing any color. In such cases, the brain cannot register even easily distinguishable color contrasts. Finally, rapid eye movement is a rare symptom for the development of this complication among children.
Age of onset
Color blindness can be acquired from birth or later in life. However, most people with colorblindness acquire the disorder at birth. This is largely attributed to the fact that congenial vision defects can be inherited from the mother. However, vascular diseases, trauma and metabolic complications can yield the development of this complication. As such, it is difficult to establish the age of onset for this genetic complication. Nonetheless, it can be estimated to commence from six months to advance ages in a person’s life (National Eye Institute, 2016).
How many people are affected?
Color blindness commonly affects the male gender as opposed to the female sex. Eight percent males and less than one percent females in the globe have this genetic disorder. As a result, it affects both genders differently depending on the type of heritage one has. The National Eye Institute (2016) reports that nearly 0.5 percent of the females and 8 percent of the males with Northern European ancestry have a common red-green type of color blindness. The institute also reports that there is a 0.25 percent of a child being born with the complication and 0.5 percent being a carrier.
Main section
Current knowledge on the disease
Defective genes that synthesize photo pigments in the cones cause the most common types of color blindness. However, alterations in the photo pigment’s sensitivity to primary colors yield this complication. The Red-Green color blindness is the most common type of disorder. It is caused by the limited or lost function of the deutran and protan photo pigments; green and red cones respectively. On the other hand, Blue-yellow color blindness is lesser common as opposed to the former. It is caused by a deficiency of the blue, photo pigment. In cases of complete color blindness, the affected individuals do not perceive color at all. There are two types of this complication namely; rod monochromacy, popularly known as achromatopsia and cone monochromacy (National Eye Institute, 2016). The former is the rare but the most severe form of color blindness. It is only present at birth where all the cone cells lack functional color pigments. As such, people with this complication see the world in white, gray and black. However, since rods only respond to dim light, the affected individuals experience discomfort in bright light, photophobic.
What treatments are available?
There is no known cure for color blindness. However, people with lesser severe types of color blindness can be issued special types of lenses to enhance their color perception. These lenses are only usable in well-lit environments and they suffer from poor color discernment in lowly lit environments. Additionally, some mobile applications have been designed to enable people to perceive the right color in the photos taken by through inversion color technology.
Is this the result of one or more genes?
The genes causing color blindness are mainly transferred on the X chromosome. As such, one gene is capable of causing this complication. Males have the X and Y-chromosomes. As a result, only dominant mutation occurs since one gene can yield this disorder. On the other hand, females have two X Chromosomes. As a result, they have a provision for being a carrier for the traits or having the disorder. Nonetheless, one gene in males and two in females cause this complication. In some cases, autosomal recessive inheritance yields the development of color blindness. In such cases, two defective genes are required to cause this complication. In dominant autosomal recession, only one gene is required to cause the disorder.
How is it inherited?
Most of the common complications are linked to the X-chromosome and are transmitted during conception. In this period, one of the male chromosomes fuses with another female chromosome to form a zygote. If the mother was a carrier and she transmits carrier chromosomes while the father is normal, there is a fifty percent probability that the child would be a carrier if she is female or color blind if she is male. Additionally, if both parents are color blind, there is a perfect chance for the child to be color blind. This complication is therefore inherited during childbirth from the parents depending on the state of the chromosomes shared by each party. However, there are some fewer cases of autosomal recessive inheritance. They require two copies of a mutant gene yield this disorder. An individual with one copy of the gene is known as a carrier (National Eye Institute, 2016). Finally, autosomal dominant inheritance requires one copy of the mutant gene to yield this complication. As such, there is a 50 percent chance of a child getting this complication depending on the nature of their child.
Conclusion
Ongoing research, potential treatments and research groups looking into the issue
The National Eye Institute has utilized gene therapy to cure color blindness in monkeys. This was achieved through injection of red photo pigments into the monkey’s retinas. This activity registered positive results as the monkey was able to perceive accurate colors after the exercise. This implies that the brain circuitry is unaffected by the eye structure. As such, it is possible to assimilate a similar activity in the human context. Additionally, studies are being conducted on how people lose color perception at advance life stages. Through this research, appropriate counseling sessions can be developed on means to reduce visual impairment chances. Additionally, the NEI is conducting a study to determine the possibility of combining gene therapy and neurophobic factors to enhance nerve cells growth. In this case, further research would be needed to determine whether this approach might be possible in enhancing the development of these genes in human beings with this genetic disorder.
References
American Academy of Ophthalmology. (2013). What Is Color Blindness? American Academy of Ophthalmology. Retrieved 25 February 2016, from http://www.aao.org/eye-health/diseases/what-is-color-blindness
National Eye Institute. (2016). Facts about Color Blindness. National Eye Institute. Nei.nih.gov. Retrieved 25 February 2016, from https://nei.nih.gov/health/color_blindness/facts_about
