Download APA Format 6th Edition Template

Running head: GENETICS OF COLORBLINDNESS
Genetics of Colorblindness
Wesley Iobst
Bayside High School
1
GENETICS OF COLORBLINDNESS
2
Abstract
Color blindness is a disorder that effects the daily lives of many people around the world, mostly
men through the genes passed from the mother. Color blindness is organized into different
categories or classifications and each presents different color vision deformities. The different
classifications are anomalous, red-green color blindness, yellow-blue color blindness, and
monochromatism (Kochman, 2014) . They can be broken into smaller sub-categories to better
diagnose a person who is colorblind. For example, monochromatism is divided into the subcategories typical and atypical (Kochman, 2014). In order to identify someone colorblind,
doctors use anomaloscopes and pigment tests as diagnosis tools (Kochman, 2014). Effected
people with the disorder face many complications in their daily life and careers. For example,
color blind people will not be accepted into the armed forces because in that particular job they
need to easily identify colors (Paul, 2014). In response to these issues, medical professionals
have designed glasses that will aid in a color blind person seeing colors (Pogue, 2013). This is a
disorder that is being researched and diagnosed by researchers and doctors every day.
Keywords:
Color blindness, anomalous, red-green color blindness, yellow-blue color blindness,
monochromatism
GENETICS OF COLORBLINDNESS
3
Genetics of Colorblindness
Think about how a person’s life would change if they did not have the ability to see color.
Some people face this reality each day due to colorblindness. Colorblindness is when a person
lacks the ability to view certain colors, mainly red, green, blue-violet, or some combinations of
these. Generally, it is inherited through the genes passed from a person’s parents but may be
caused by damage to the eyes (WebMD, 2011). These people with this disorder have to take
precautions to deal with the defects; however, that usually is not a big deal (Paul, 2014).
Colorblindness cannot be understood without knowing the different types of color blindness,
causes, diagnosis, treatment, and difficulties of color blindness.
Anomalous
There are four different types of color blindness, one being anomalous. This is the most
common type of color defect and these defects are found in around 6% of the white male
population (Kochman, 2014). Despite anomalous color defects being the most frequent type of
color vision disorder, the defects are often less significant than other types of color blindness. A
color-anomalous person is able to see all the primary colors but the person’s red and green color
responses do not react as well as a normal person’s (Kochman, 2014). Protanomalous and
deuteranomalous are the two sub categories scientist have identified. Both categories have
problems seeing green and see certain areas of the color spectrum as desaturated (Kochman,
2014). A protanomalous individual has more difficulty when identifying long red wavelengths
and sees them as darkened (Kochman, 2014).
Red-green Color Blindness
Red-green color blindness is the second most common form of color blindness and is
found in 2% of white males. These people have no ability of seeing red and green, and they can
GENETICS OF COLORBLINDNESS
4
only see the world in shades of yellow, blue, and gray (Kochman, 2014). The only difference
between red and green to them is luminosity; therefore, it is difficult for them to recognize red
and green. These individuals lack the ability to see mixtures of red and green, such as orange,
blue-green, and violet (Kochman, 2014). Red-green color blind people are further distinguished
into protanopes and deuteranopes. Each group sees a small colorless area on the color spectrum
where a normal person would see green (Kochman, 2014). The protanope group is further
described by the fact that the entire color spectrum is shortened therefore longer wavelengths are
invisible. Red-green color blindness is most commonly inherited than as a result from an injury
or disease of the eye’s optic nerve or the optic cortex, the section of the brain in control of vision
(Kochman, 2014).
Yellow-blue Color Blindness
Yellow-blue color blindness is the second rarest color vision defect. This person is unable
to see any shades of yellow or blue and views the world in shades of red, green, and gray
(Kochman, 2014). Contrary to red-green color blindness, a yellow-blue colorblind person sees
two colorless areas of the color spectrum, yellow and blue. Most likely a yellow-blue color blind
person has acquired the disorder through a retina disease or cataracts (Kochman, 2014). Yellowblue colorblindness is unlike other types of color blindness where it is usually inherited from the
person’s parents. Less is known about this type of color blindness, including the genetic
inheritance pattern (Kochman, 2014).
Monochromatism
The final type of color blindness is monochromatism and it is the rarest form of the
disorder. In monochromatism cases the person will see the world in only shades of black and
white (Kochman, 2014). Scientists have broken the disorder in to two categories: typical and
GENETICS OF COLORBLINDNESS
5
atypical. Symptoms of a typical case is very poor vision, nystagmoid eye movement (rapid
involuntary movement of the eyes), and a hypersensitivity to light (Kochman, 2014). The
atypical form of monochromatism is less severe than the typical form; the person only suffers
from loss of color vision. Usually monochromatism deficiencies are inherited but in some cases
eye disease have resulted in complete color blindness of a person (Kochman, 2014).
Causes of Color Blindness
Color blindness is most commonly inherited through a genetic defect of the long arm of
the X chromosome. Since men only have one X chromosome, they have a greater chance of
obtaining the disorder; where as women have two X chromosomes leading to a decreased chance
of having the disorder (Paul, 2014). Some studies have concluded that some women with one
affected X chromosome have small defects in their color vision. Another cause of the disorder is
a disease of the retina or optic nerve (Paul, 2014). Typically this leads to yellow-blue color
blindness rather than other types of color blindness (Paul, 2014). Some examples of diseases
know to lead to colorblindness are glaucoma, macular degeneration, cataracts and diabetic
retinopathy. Also, aging and side effects of certain medications can lead to color blindness
(WebMD, 2011).
Diagnosis of Color Blindness
Color blindness is typically during routine vision tests during a person’s childhood or
during medical tests for certain jobs that require normal color vision (Complete Home Medical
Guide, 2004). The two ways of identifying if someone is color blind is an anomaloscope and
pigment tests. An anomaloscope is an instrument invented by Willibald Nagel in 1907 used to
diagnose red-green color blindness and anomalous color blindness (Kochman, 2014). The
subject is presented with two viewing fields. One of the slides has pure yellow light and the other
GENETICS OF COLORBLINDNESS
6
contains red and green light (Kochman, 2014). The person must mix the red and green light to
match the adjacent yellow slide by turning knobs. A deuteranomalous person typical will create a
viewing field with more green, and a protanomalous individual will create a match that has more
red (Kochman, 2014). Along with the anomaloscope, pigment tests can be used to diagnose a
color blind person. The most commonly used tests are the pseudoisochromatic plates, HardyRand-Rittler, Velhagen, and Dvorine plates (Kochman, 2014).Displayed on these plates are
either a number or pattern, and the task of the person is to identify the figure from the
background (Kochman, 2014).
Treatment of Color Blindness
Despite inherited color blindness being non-treatable, there is ways to improve that
person’s color vision. Colored contacts can be worn to increase the contrast among colors
(A.D.A.M., 2001). For example, if a person is red-green color blind then wearing a red-tinted
lens will make green appear darker. This allows the person to differentiate between the colors
(A.D.A.M., 2001). If an underlying cause is the reason for a person’s color blindness, then that
can usually be treated. For example, if a cataract is the source of color blindness, it can be
removed and normal color vision can be restored (WebMD, 2011). Another remedy of color
blindness is wearing special glasses. These glasses were originally designed to help doctors, but
they ended up being able to cure red-green color blindness (Pogue, 2013). New York Times
writer, David Pogue, wrote an article describing his experience with the glasses. For the first
time ever he saw colors that he never imagined, but the only downfall was that they only worked
in bright areas (Pogue, 2013). He determined that they were not worth their outrageous price of
$600 because he does not view color blindness as a handicap (Pogue, 2013).
Difficulties of Color Blindness
GENETICS OF COLORBLINDNESS
7
Even though a color blind person may not have the most severe difficulties, they still face
them every day. Color blind people should ask people for help when they think they need it and
take extra precautions. For example, they have to pay close attention to the location of the light
of traffic lights (Paul, 2014). Additionally, some jobs require normal color vision so color blind
people are excluded. For example, an electrician must be able to distinguish the colors of wires
(A.D.A.M., 2001). Children with color vision problems may have difficulties learning and
reading, leading to poor school work and self-esteem. It is suggested that parents have their child
tested for color blindness during eye exams (WebMD, 2011). Also, if a child is color blind, their
parents should notify their teacher so the teacher can make accommodations for the child
(WebMD, 2011).
Conclusion
Colorblindness is a disorder that is depleting life experience for people with it. The world
without color is like watching a black and white television show, it is not as enjoyable as
watching a television show in color. It cuts opportunities, like career choices, out of the lives of
colorblind people. A cure should be further investigated for those who do not have as many
choices in life. It can only help.
GENETICS OF COLORBLINDNESS
8
References
Color blindness. (2004). Complete Home Medical Guide. Dorling Kindersley. Retrieved from
http://elibrary.bigchalk.com
Eye Health Center: Topic Overview (2011, April 15).WebMD. Retrieved January 12, 2014 from
http://www.webmd.com/eye-health/tc/color-blindness-topic-overview.
Kochman, R. S. (2014). Color Blindness. Encyclopedia Americana. Retrieved January 9, 2014,
from Grolier Online http://ea.grolier.com/article?id=0101700-00
Paul, M. D. (2014). Color Blindness. Grolier Multimedia Encyclopedia. Retrieved January 9,
2014, from Grolier Online http://gme.grolier.com/article?assetid=0067700-0
Pogue, D. (2013, August 15). Glasses That Solve Colorblindness, for a Big Price Tag. New York
Times. Retrieved January 12, 2014 from
http://pogue.blogs.nytimes.com/2013/08/15/glasses-that-solve-colorblindness-for-a-bigprice-tag/?_r=0.
Why are some people color-blind?. (2001). A.D.A.M. Life's Greatest Mysteries. A.D.A.M.
Software. Retrieved from http://elibrary.bigchalk.com