Congenital color vision defects usually pass from mother to son. These defects are due to partial or complete lack of cones in the retina. Cones help you to distinguish the colors red, green, and blue. Color vision defects from disease are less understood than congenital color vision problems.
Disease-specific color blindness often affects both eyes differently. Color vision defect caused by disease usually gets worse over time. Acquired color vision loss can be the result of damage to the retina or optic nerve. Men are at much higher risk for being born with color blindness than women, who seldom have the problem. An estimated one in ten males has some form of color deficiency. Color blindness is more common among men of Northern European descent. Certain drugs may also increase your risk for acquiring color blindness.
The drug hydroxychloroquine Plaquenil can cause color blindness. It is used to treat rheumatoid arthritis, among other conditions.
Your ophthalmologist will be able to conduct a simple test to determine if you have color blindness. The test consists of showing you a pattern made up of multi-colored dots. If you do not have a color deficiency, you will be able to see numbers and shapes among the dots. If you are color blind, you will have a hard time finding the number or shape in the pattern. You may not see anything in the pattern at all. Three different kinds of cones absorb various wavelengths of light, and each kind reacts to either red, green, or blue.
The cones send information to the brain to distinguish colors. The majority of color vision deficiency is inherited. It typically passes from mother to son. With glaucoma , the internal pressure of the eye, or the intraocular pressure, is too high. The pressure damages the optic nerve , which carries signals from the eye to the brain so that you can see. As a result, your ability to distinguish colors may diminish.
Macular degeneration and diabetic retinopathy cause damage to the retina, which is where the cones are located. This can cause color blindness. In some cases, it causes blindness. If you have a cataract , the lens of your eye gradually changes from transparent to opaque. Your color vision may dim as a result. Certain medications can cause changes in color vision. These include the antipsychotic medications chlorpromazine and thioridazine. The antibiotic ethambutol Myambutol , which treats tuberculosis , may cause optic nerve problems and difficulty seeing some colors.
Color blindness may also be due to other factors. One factor is aging. Vision loss and color deficiency can happen gradually with age. Additionally, toxic chemicals such as styrene, which is present in some plastics, are linked to the loss of ability to see color. Seeing colors is subjective. However, your eye doctor can test for the condition during a normal eye exam. Testing will include the use of special images called pseudoisochromatic plates.
American Academy of Ophthalmology. Accessed Sept. Kliegman RM, et al. Examination of the eye. In: Nelson Textbook of Pediatrics. Elsevier; Facts about color blindness. National Eye Institute. Bennett CR, et al. The assessment of visual function and functional vision. Seminars in Pediatric Neurology. Yanoff M, et al.
Molecular genetics of selected ocular disorders. In: Ophthalmology. Search the site. Print this Page. Causes of Color Blindness. Learn the basics about color blindness. What causes color blindness? How is color blindness passed down from parents?
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