Colour blindness is the inability to view the entire spectrum of colours easily in which either colour is completely removed from vision or only certain pigments such as greens or reds are unidentifiable. Though there are many causes for the inability to see in full colour such as trauma to the brain or the eye(s) much can be attributed to genetic linkage. It is important to note that the term colour blindness is frequently used incorrectly as it is very rare for an individual to be completely colour blind which is known as Achromatopsia (Johnson S, 2004) though in most cases only certain colours are skewed or unrecognisable. It is well known that the studying of colour blindness was started by John Dalton who was in fact colour blind himself, he would publish a paper in 1798 on the topic which would start future scientific research (Dalton, 1999). Lastly colour blindness is known to effect men much more than it does in women as approximately 8% of males are colour blind in some form or another compared to women at a measly 0.5% (Karl R. Gegenfurtner, 2001).
Symptoms of colour blindness can be hard to detect if an individual has been exposed to large amounts of colour in their lifetime, a slight difference in how different people perceive colour can be difficult to compare without proper testing. Most times a colour may look “off” or the colour deficient person will not be able to tell different shades apart for example lime green compared to olive green. Other symptoms are usually seen by an individual who may have recently suffered an injury or disease to certain parts on their body that can affect colour identification, in which depending on severity of the change a person may or may not notice this change. For example, if two people would view the title page of this assignment of the name David Alexander one may say the blue is just blue or another may say ocean or sky blue, both responses are no more correct or incorrect as the other this is because of opinion based on how we perceive colour. Just by looking at something is not clear evidence if your shades of blue are correct or incorrect which is why singular pigment deficiency may go forever unnoticed if there is only a slight difference.
The most common form of color blindness is by genetic inheritance in which there is a possibility of 19 different chromosomes as well as genes being responsible for colour blindness (Sciences, 2006). However, there are other forms in which colour blindness can occur such as retina or cones diseases that progress until an individual can no longer intake some types of light with colour for example Blue cone monochromacy in which the colour blue cannot be seen by the individual (Alpern, 1974). Other ways to become colour blind or deficient include massive head trauma especially to optical nerve, overexposure to bright light e.g. staring at the sun or tanning salon as well as simply old age.
The reason why colour blindness is inherited mostly in males is because of the lack of only one X chromosome as in females whom carry two x chromosomes. If one of the x chromosomes do in fact contain colour blindness and the other X chromosome is normal the normal will be the dominant one and colour blindness is happily averted. Though because males have only one X chromosome the chances are raised to 5% as there is no alternative x chromosome to the one you have received. Though it is possible for females to become colour blind in some way but it must take both parents to have colour blindness passed down into that child with both colour blind genes being chosen during the random selection of the 23 chromosomes from each parent during conception in order to have a slim 0.5% chance of their female child being colour blind. In essence a male only needs one of his parents to be either colour blind or have the recessive trait in order for his x and ultimately him to be colour blind though females need both X's to be effected in order to be colour blind.
Currently, there are no treatments available for those that suffer from colour blindness as it is extremely hard to remove genes from a person let alone repair them itself. There has only been ways to assist those by using computers or certain sounds to represent a colour though because of the sophistication and intricacies of the human eye, nothing substantial has been created as of yet. In one experiment researchers at the University of Washington and the University of Florida were able to give a dichromatic squirrel monkey human vision or more commonly known as trichromatic vision or seeing in 3 colours which was done by using gene therapy (Dolgin, 2009).
Alpern. (1974). Typical and atypical monochromacy studied by specific quantitative perimetry. Acta Ophthalmol , 24.
Dalton, J. (1999). Extraordinary facts relating to the vision of colours: with observations. Memoirs of the Literary and Philosophical Society of Manchester , 28-45.
Dolgin, E. E. (2009, September 16). Retrieved March 2, 2010, from http://www.bioedonline.org: http://www.bioedonline.org/news/news.cfm?art=5621
Johnson S, M. M. (2004). Achromatopsia caused by novel mutations in both CNGA3 and CNGB3. Journal of Medical Genetics , 61.
Karl R. Gegenfurtner, L. T. (2001). Color vision: from genes to perception . Cambridge: Cambridge University Press.
Sciences, U. o. (2006). Colour Blindness. Chicago.