Colorblindness
The inability to perceive colors in a normal fashion. The most common forms of colorblindness are inherited as sex-linked (X-linked) recessive traits. Females are carriers and males are affected. As a result, approximately 1 in 8 males is colorblind as compared to less than 1 in 100 females. The most common form of colorblindness is red-green. There is a wide range of variability within this group from very mild to extreme. The second most common form is blue-yellow. A red-green deficit is almost always associated with this form. The most severe form of colorblindness is achromatopsia, the inability to see any color. It is often associated with other eye problems such as amblyopia (lazy eye), nystagmus, photosensitivity, and extremely poor vision. The symptoms of red-green and blue-yellow colorblindness may be so mild that affected people are unaware they are colorblind unless specifically tested. Parents may notice colorblindness in a more severely affected child at the time the child would normally learn colors. Several color vision tests are available through a primary physician or an eye specialist (ophthalmologist). Testing for colorblindness is commonly performed along with other vision screenings. There is no known treatment. People with this condition need to learn to cope. Colorblindness is a life-long condition. Colorblindness may exclude people from some jobs, such as being a pilot, where color vision is essential. People with red-green colorblindness may also fail to notice the presence of blood in the urine and stool.
Medical dictionary.
2011.