Color Blindness
Many people refer to problems with one’s ability to see color as color blindness, however, unless a person can’t see any color at all, color vision problems should be called by another term. Common terms are abnormal color vision, color deficiency and color vision confusion. Females maybe be effected by color blindness, but usually they are just carriers. Males are more often affected. About 8% of males and 0.5% of females are effected by color blindness.
Although color blindness may be a result of another eye disorder, the majority of color blind cases are hereditary and present at birth.
The retina, is a complex nerve system which converts light energy into electrical energy that is then transmitted to the brain. This conversion is accomplished by two types of receptor cells in the retina called rods and cones do to their shape. The cones are responsible for converting the color. Each cone contains visual pigments that are sensitive to one of three wavelengths of light: red, green and blue. Normally, all colors of the spectrum are able to be matched by mixtures of only three color sensitivities. Therefore, the huge variety of colors we see are a response to different compositions of wavelengths
of light. The rods are responsible for encoding white and black.
Color blindness results when one or more of the cone cells fail to function properly. One of the visual pigments may be functioning abnormally, or be absent altogether.
...
Supposedly, a freak typhoon-like storm ravaged the island in the late eighteenth century and killed a number of the island's inhabitants. Approximately 20 people survived to replenish the isolated island's population. Roughly four generations after the typhoon, the citizens of Pingelap began exhibiting symptoms of a rare recessive disorder known as Achromatopsia. Achromatopsia is characterized by extreme light sensitivity, poor vision, and complete inability to distinguish colors (3). This anomaly is the focus of Oliver Sacks' new book The Island of the Colorblind and its publication has succeeded in raising public awareness about the rare hereditary disease of Achromatopsia. Of the roughly the 3000 people living in Pingelap today, 5% to 10% of them are affected by the disorder and about 30% are carriers (3). All of these people are able to trace their ancestry to a single male typhoon survivor who researchers believe was the carrier of the disease that emerged when some of his descendents intermarried (3).
Retinitis pigmentosa is a genetic disorder that causes blindness in the people that are affected by it. I chose retinitis pigmentosa because my grandmother has this genetic disorder. The disorder is very costly on those who have it. The disorder has robbed my grandmother of the life she wanted. She is no longer able to do the things she once was. She is legally blind, cannot drive, and has trouble getting around crowded areas. Retinitis pigmentosa was discovered by Doctor Donders in 1857. Retinitis pigmentosa is a very serious disorder in how it occurs, its signs and symptoms, its prevalence, and how its treated.
When we open our eyes, millions of tiny events occur that allow us to see. Our pupils automatically constrict in accordance to the light level, the variable lens bends and adjusts to fit the distance of what we are looking, and our photoreceptors receive information in accordance to the previous factors. (This is extremely simplified, but it will suffice for now.) Photoreceptors are tiny, specialized neurons located in the retina at the back of the eye. There are two types of photoreceptors, rods and cones. Each follow the same principles: when light hits them they respond with a chemical reaction using a substance known as rhodopsin. Once this reaction occurs a chain of events sends this message down a number of sophisticated and specialized neurons, eventually reaching the brain and resulting in what we call sight.
Young-Helmholtz trichromatic (three color) theory: The theory that the retina contains three different color receptors-one most sensitive to red, one to green, one to blue-which when stimulated in combination can produce the perception of any color.
Albinism is a genetic disorder that is caused by the lack of pigments. Sometimes it only affects the eye which is called ocular albinism. You can receive albinism from your genetics. You can be an albino in your eyes, skin or hair. It affects people of all races and all around the world. Studies show one in 20,000 people worldwide have some form of albinism. Certain forms of albinism are more common in some populations. Most common form of albinism is OCAZ and is found in one in 36, 0000 Caucasians in the United States. There are four types of albinism; type 1 is characterized by white hair, very pale skin, and light colored eyes. Type 2 is less severe their skin is usually a creamy white color and their hair could be a light yellow, blonde or light brown. Type 3 has a form of albinism called “rufous oculocutaneous albinism” this usually affects dark-skinned people. They have reddish-brown skin, ginger or red hair and hazel or brown eyes. Type 3 has milder vision problems. Type 4 has the same symptoms similar to type 2. Types 1 and 2 are the most common forms; types 3 and 4 are not as common.
When I was young, I was told that "color blindness" did not mean that the person saw the world like an old movie, but rather it meant that they could not distinguish between green and red. I thought that this understanding was very advanced and would quickly share my knowledge with any less-informed children. After looking into the matter, I have been forced to reject this generalization in favor of a broader range of diseases resulting in very different types of inabilities to perceive color in a "normal" fashion. While the typical color blindness I was told about affects 8 percent of men and less than 1 percent of women in the United States (1), there are many other types. The most common types of color blindness, effecting red and green vision, are not too serious for the sufferers, who can function normally and do not have overly impaired vision other than an inability to distinguish between certain colors. There are, however, more serious forms of "color blindness", such as blue cone monochromatopsia, partial rod monochromatopsia, and total rod monochromatopsia (3). The rod monochromats are also known as achromats, meaning they see no color at all. Only about 1/33,000 Americans has this disease, and women and men are effected roughly equally (3). This most severe variety of color blindness has many interesting symptoms which reveal a lot about rod vision.
Colorblindness affects more people than you might think, around 1 in every 12 males have color blindness (CBA). Although it is more common for boys to have color blindness girls can also get it, about 1 in 200 girls will have colorblindness (CBA). Look around you; chances are someone you know has colorblindness. There is nothing these people can do about it; it is a genetic disease.
An Anthropologist on Mars by Oliver Sacks introduces seven neurological cases that happens to people around the world. Sacks deals with different aspects of the brain, such as, the lobes of the brain, perception, and neurological disorders. One of the cases Sacks mentions is “The Case of the Colorblind Painter”. The case involves an artist who can’t see color due to an accident he encountered. His colorblindness affects his daily life, including his dreams; he doesn’t see a wide range of colors in his life, only what he describes it as “a black and white tv screen”. When I was reading his case, I found it intriguing that one can develop colorblindness from an accident. I always thought that colorblindness was a genetic thing, but the fact that at any given moment, it can activate shows that the brain has more mysterious than intended. The powerful emotional aspect of the case makes it more powerful and shows a deep theme. It makes me realize that I shouldn't take anything for granted because at any given moment, something can be taken away.
Blindness is a disease that causes the eye to not see clearly. Cataracts, most common disease for blindness, is a very serious disease and can cause death (Hal, 13). Cataracts affects almost twenty million American people (Hal, 13). Dome of the most common causes that can cause blindness are Diabetes, smoking, drinking, and lack of nutrition (Medicine Net, web).
Color Vision Development in Infants: The Responsibility of Cone Types and Wavelength in Order of Color Development
Rods are responsible for vision at low light levels they do not mediate color vision, and have a low spatial acuity. Rods are more sensitive to light then cones. Cones are active at higher light levels and are capable of color vision and are responsible for high spatial acuity resulting in sharp images. Rhodopsin is the light sensitive pigment in rods. Rhodopsin molecules break down into a protein called opsin and an organic compound called retinal which manufactures vitamin A. Iodines are the light sensitive pigments of cones. They contain different proteins than the
Colour vision refers to the ability of an organism to distinguish between stimuli based on the wavelengths of light they emit, reflect or transmit. We live in a world filled with colours which we use as an advantage on a day-to-day basis; to signify danger, make things stand out and to help us categorise the world around us. However, 1 in 12 males and 1 in 200 females (approximately 4.5% of the population) suffer from some sort of colour vision deficiency or blindness (Colour Blind Awareness, 2014). It is therefore of interest to investigate what is different about the visual system in this minority and why the occurs. This essay will investigate this by considering what ‘colours’ actually are in terms of wavelengths of light, investigating the differences of what we perceive to be a ‘coloured’ world based on the different visual systems of non-human animals. Finally it will look at what makes the system of colour blind humans different, questioning whether we can really consider them colour blind at all.
The absence of cones, to retina is not damaged and the achromatopsia may also experience excellent acuity. Transient achromatopsia that is a temporary loss of color vision that is caused by a short lived vascular in sufficiency, apparently to V1 and the V2 in the occipital cortex. Many people how suffer from strokes or mild cerebral infections have been observed to display temporary loss of color vision. Chromatopsias are common of color distortion than an outright deficiency. Patients suffering from chromatopsias simply do not perceive certain colors as well as others. Phantom chromatopsia has a rare disorder that deals with patients who are blind or nearly
People with ocular albinism, which only the eye lacks melanin pigment, while everything else appears normal. People who have this have a variety of the eye disorders because of the lack of pigment impairs normal eye development. These effected are extremely sensitive to bright light. Treatment for ocular albinism includes the use of visual aids and surgery for strabismus.
Color Blindness means that you have trouble seeing the colors green, blue, or red or a mix of these colors. It is an abnormal condition characterized by the inability to clearly distinguish different colors of the spectrum. It is very rare that a person doesn’t see any color at all. Color Blindness is also called color vision problem. The difficulties can range from mild to severe. Color blindness is a misleading term because people that have it aren’t really totally blind. They tend to see colors in a limited range of hue. The scientific name for total color blindness is Monochromasy. Having color blindness would change a normal person’s life. It makes it harder to read and learn, and you may not be able to have certain careers. Although having color vision problems can affect your life greatly, you can still learn to make up for your problems seeing color. There are many other types of color vision problem. Deuteranomaly is a type that is considered green weak. Dichromasy is another type, which can be divided into Protanopia and Deuteranopia. People with this see no difference between red, orange, yellow, and green. Protanopia has much reduced color vision of the colors red, orange, and yellow. Deuteranopia is the same thing as Protanopia except without the abnormal dimming which makes it different. Last would be Tritanopia and Tritanomoly. Both of these types of color blindness are blue-green –color blindness with not many differences between them. In Tritanopia the s-cones are completely missing from the eye, and in Tritanomoly the s- cones have some kind of mutation.