Color blindness, or color vision deficiency, refers to the inability of a person to correctly distinguish certain colors. Many people mistakenly believe that to be color blind is to view the world in only black and white, but complete color blindness is rare. A color-blind person usually has problems distinguishing certain colors, mistaking them for the same color.
In our eyes, there are cells known as cones that help us differentiate colors. There are three different types of cones—one allowing us to see red, one allowing us to see green, and another allowing us to see blue. When one has color blindness, one or multiple cone types are either absent or not functioning properly, resulting in themnot seeing certain colors or seeing colors differently.
Types of Color Blindness
About 8% of men and 0.4% of women are color vision deficient.There are different types of color blindness, with some being more common than others.
Red-Green Color Blindness
A color-blind person usually has problems distinguishing between the colors red and green, mistaking them for the same color. This type of color blindness is the most common. The different types ofred-green color blindnessare:
Red-Green Color Blind Tests
Yellow-Blue Color Blindness
While red-green color blindness makes it hard to distinguish between red and green, yellow-blue color blindness makes it hard to tell the difference between blue and green and between yellow and red. Occurring in fewer than one in 10,000 people worldwide, this type of color blindness is less common and affects males and females equally.
There are two types of yellow-blue color blindness:
Complete Color Blindness
A person with complete color blindness or completeachromatopsiahas no functional cones and cannot see any colors.Sometimes, a person may have incomplete achromatopsia in which there are some functional cones, only allowing them to see certain colors. Those with achromatopsia commonly have impaired vision, light sensitivity, andnystagmus.
Achromatopsia in general is rare and is estimated to affect one in 30,000 people worldwide, with complete achromatopsia being more common than incomplete achromatopsia.
The different types of color blindness.Melillo P, Riccio D, Di Perna L, et al. / IEEE J Transl Eng Health Med
Melillo P, Riccio D, Di Perna L, et al. / IEEE J Transl Eng Health Med
Causes
Color blindness is usually hereditary, meaning that the condition is typically passed down from parents.Occasionally, certain diseases can affect the eyes or the brain and cause color blindness, referred to as “acquired color blindness.” Some of these diseases include:
Some medications, notably Plaquenil (hydroxychloroquine), can affect the cells in the eyes and sometimes cause color blindness.Aging can also cause the disorder; as the lens darkens with age, older people may find it difficult to distinguish colors.
Symptoms
The main symptom of color blindness is difficulty distinguishing between red and green or blue and yellow. Parents will often suspect color blindness when their child has difficulty learning colors. Children having problems at school should be tested for color blindness, as many learning materials rely heavily on students being able to differentiate between colors.
Diagnosis
The most common test for diagnosing color blindness is the Ishihara test.This quick and simple test consists of a series of pictures made up of colored dots. Among the dots is a figure, usually, a number made up of dots of a different color. A person with normal color vision will be able to see the number, but a color-blind person will see a different number or no number at all.
The Ishihara test.American Optometric Association
American Optometric Association
Another test used to diagnose color blindness is called an arrangement or hue test, in which the patient is asked to arrange a group of colored chips or blocks in a particular order.
Treatment
Unfortunately, there is no cure for color blindness. However, people with color vision deficiencies learn ways to cope with the disorder. Patients usually teach themselves how to differentiate between different colors and shades of colors.
Some doctors prescribecolor-corrective lenses, depending on the severity of the color vision deficiency.Additionally, there are computer software and phone applications that help those with color vision disorders.
Adjusting
If you have color blindness, there are many strategies that can help you accomplish everyday tasks and recognize colors easily. First, you can talk to your doctor about contact lenses or glasses designed for those with color blindness. Such contacts and glasses may help differentiate between colors you have difficulty seeing.
There are also smartphone apps that use your phone’s camera to name colors, which can be helpful when shopping for clothes or other items and knowing the colors of your surroundings.
You can also ask those around you about colors you have difficulty seeing, especially the staff of the store you’re visiting.
In the United States, it’s legal to drive if you’re color blind. Traffic light colors are strategically ordered to help drivers know which light is displaying.For vertical lights, the red light (stop) is always at the top, the green light (go) is always on the bottom, and the yellow light (slow down) is always in the middle.
For horizontal lights, the red light (stop) is always on the left side, the green light (go) is always on the right side, and the yellow light (slow down) is always in the middle.
A Word From Verywell
Color blindness is a rare condition that causes very few limitations for those affected. By knowing strategies like memorizing traffic lights and utilizing implements like color-corrective lenses, those with color blindness are often able to adjust and live normal lives.
21 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Library of Medicine MedlinePlus.Color Blindness.Lamb TD.Why rods and cones?Eye (Lond). 2016;30(2):179-185.doi: 10.1038/eye.2015.236Barry JA, Mollan S, Burdon MA, Jenkins M, Denniston AK.Development and validation of a questionnaire assessing the quality of life impact of Colour Blindness (CBQoL).BMC Ophthalmol. 2017;17(1):179. doi:10.1186/s12886-017-0579-zNational Eye Institute.Types of color blindness.National Library of Medicine MedlinePlus.Color vision deficiency frequency.National Library of Medicine National Center for Biotechnology Information.Achromatopsia.American Association for Pediatric Ophthalmology.Achromatopsia.MedlinePlus.Achromatopsia.https://medlineplus.gov/genetics/condition/achromatopsia/#frequencyShichi H. Color Blindness. In: Siegel GJ, Agranoff BW, Albers RW, et al., editors. Basic Neurochemistry: Molecular, Cellular and Medical Aspects. 6th edition. Philadelphia: Lippincott-Raven; 1999. Available from:https://www.ncbi.nlm.nih.gov/books/NBK27990/National Eye Institute.Causes of color blindness.Niwa Y, Muraki S, Naito F, Minamikawa T, Ohji M.Evaluation of acquired color vision deficiency in glaucoma using the rabin cone contrast test.Invest Ophthalmol Vis Sci. 2014;55(10):6686. doi: 10.1167/iovs.14-14079Olsen TW, Bottini AR, Mendoza P, Grossniklausk HE.The age-related macular degeneration complex: linking epidemiology and histopathology using the minnesota grading system (The inaugural frederick c. Blodi lecture).Trans Am Ophthalmol Soc. 2015;113:Blodi.PMID: 27895380Kim HJ, Ryou JH, Choi KT, Kim SM, Kim JT, Han DH.Deficits in color detection in patients with Alzheimer disease.PLOS ONE. 2022;17(1):e0262226. doi: 10.1371/journal.pone.0262226Lampert EJ, Andorra M, Torres-Torres R, et al.Color vision impairment in multiple sclerosis points to retinal ganglion cell damage.J Neurol. 2015;262(11):2491-2497. doi: 10.1007/s00415-015-7876-3Pandya H, Robinson M, Mandal N, Shah V.Hydroxychloroquine retinopathy: A review of imaging.Indian J Ophthalmol. 2015;63(7):570. doi: 10.4103/0301-4738.167120American Academy of Opthalmology.Testing Children for Color Blindess.Fanlo Zarazaga A, Gutiérrez Vásquez J, Pueyo Royo V.Review of the main colour vision clinical assessment tests.Arch Soc Esp Oftalmol (Engl Ed). 2019;94(1):25-32. doi:10.1016/j.oftal.2018.08.006National Eye Institute.Testing for color blindness.Badawy AR, Hassan MU, Elsherif M, Ahmed Z, Yetisen AK, Butt H.Contact lenses for color blindness.Adv Healthcare Mater. 2018;7(12):1800152. doi: 10.1002/adhm.201800152Fliotsos MJ, Zhao J, Pradeep T, Ighani M, Eghrari AO.Testing a popular smartphone application for colour vision assessment in healthy volunteer subjects.Neuro-Ophthalmology. 2021;45(2):99-104. doi: 10.1080/01658107.2020.1817947El-taher FE zahraa, Taha A, Courtney J, Mckeever S.A systematic review of urban navigation systems for visually impaired people.Sensors. 2021;21(9):3103. doi: 10.3390%2Fs21093103
21 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Library of Medicine MedlinePlus.Color Blindness.Lamb TD.Why rods and cones?Eye (Lond). 2016;30(2):179-185.doi: 10.1038/eye.2015.236Barry JA, Mollan S, Burdon MA, Jenkins M, Denniston AK.Development and validation of a questionnaire assessing the quality of life impact of Colour Blindness (CBQoL).BMC Ophthalmol. 2017;17(1):179. doi:10.1186/s12886-017-0579-zNational Eye Institute.Types of color blindness.National Library of Medicine MedlinePlus.Color vision deficiency frequency.National Library of Medicine National Center for Biotechnology Information.Achromatopsia.American Association for Pediatric Ophthalmology.Achromatopsia.MedlinePlus.Achromatopsia.https://medlineplus.gov/genetics/condition/achromatopsia/#frequencyShichi H. Color Blindness. In: Siegel GJ, Agranoff BW, Albers RW, et al., editors. Basic Neurochemistry: Molecular, Cellular and Medical Aspects. 6th edition. Philadelphia: Lippincott-Raven; 1999. Available from:https://www.ncbi.nlm.nih.gov/books/NBK27990/National Eye Institute.Causes of color blindness.Niwa Y, Muraki S, Naito F, Minamikawa T, Ohji M.Evaluation of acquired color vision deficiency in glaucoma using the rabin cone contrast test.Invest Ophthalmol Vis Sci. 2014;55(10):6686. doi: 10.1167/iovs.14-14079Olsen TW, Bottini AR, Mendoza P, Grossniklausk HE.The age-related macular degeneration complex: linking epidemiology and histopathology using the minnesota grading system (The inaugural frederick c. Blodi lecture).Trans Am Ophthalmol Soc. 2015;113:Blodi.PMID: 27895380Kim HJ, Ryou JH, Choi KT, Kim SM, Kim JT, Han DH.Deficits in color detection in patients with Alzheimer disease.PLOS ONE. 2022;17(1):e0262226. doi: 10.1371/journal.pone.0262226Lampert EJ, Andorra M, Torres-Torres R, et al.Color vision impairment in multiple sclerosis points to retinal ganglion cell damage.J Neurol. 2015;262(11):2491-2497. doi: 10.1007/s00415-015-7876-3Pandya H, Robinson M, Mandal N, Shah V.Hydroxychloroquine retinopathy: A review of imaging.Indian J Ophthalmol. 2015;63(7):570. doi: 10.4103/0301-4738.167120American Academy of Opthalmology.Testing Children for Color Blindess.Fanlo Zarazaga A, Gutiérrez Vásquez J, Pueyo Royo V.Review of the main colour vision clinical assessment tests.Arch Soc Esp Oftalmol (Engl Ed). 2019;94(1):25-32. doi:10.1016/j.oftal.2018.08.006National Eye Institute.Testing for color blindness.Badawy AR, Hassan MU, Elsherif M, Ahmed Z, Yetisen AK, Butt H.Contact lenses for color blindness.Adv Healthcare Mater. 2018;7(12):1800152. doi: 10.1002/adhm.201800152Fliotsos MJ, Zhao J, Pradeep T, Ighani M, Eghrari AO.Testing a popular smartphone application for colour vision assessment in healthy volunteer subjects.Neuro-Ophthalmology. 2021;45(2):99-104. doi: 10.1080/01658107.2020.1817947El-taher FE zahraa, Taha A, Courtney J, Mckeever S.A systematic review of urban navigation systems for visually impaired people.Sensors. 2021;21(9):3103. doi: 10.3390%2Fs21093103
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
National Library of Medicine MedlinePlus.Color Blindness.Lamb TD.Why rods and cones?Eye (Lond). 2016;30(2):179-185.doi: 10.1038/eye.2015.236Barry JA, Mollan S, Burdon MA, Jenkins M, Denniston AK.Development and validation of a questionnaire assessing the quality of life impact of Colour Blindness (CBQoL).BMC Ophthalmol. 2017;17(1):179. doi:10.1186/s12886-017-0579-zNational Eye Institute.Types of color blindness.National Library of Medicine MedlinePlus.Color vision deficiency frequency.National Library of Medicine National Center for Biotechnology Information.Achromatopsia.American Association for Pediatric Ophthalmology.Achromatopsia.MedlinePlus.Achromatopsia.https://medlineplus.gov/genetics/condition/achromatopsia/#frequencyShichi H. Color Blindness. In: Siegel GJ, Agranoff BW, Albers RW, et al., editors. Basic Neurochemistry: Molecular, Cellular and Medical Aspects. 6th edition. Philadelphia: Lippincott-Raven; 1999. Available from:https://www.ncbi.nlm.nih.gov/books/NBK27990/National Eye Institute.Causes of color blindness.Niwa Y, Muraki S, Naito F, Minamikawa T, Ohji M.Evaluation of acquired color vision deficiency in glaucoma using the rabin cone contrast test.Invest Ophthalmol Vis Sci. 2014;55(10):6686. doi: 10.1167/iovs.14-14079Olsen TW, Bottini AR, Mendoza P, Grossniklausk HE.The age-related macular degeneration complex: linking epidemiology and histopathology using the minnesota grading system (The inaugural frederick c. Blodi lecture).Trans Am Ophthalmol Soc. 2015;113:Blodi.PMID: 27895380Kim HJ, Ryou JH, Choi KT, Kim SM, Kim JT, Han DH.Deficits in color detection in patients with Alzheimer disease.PLOS ONE. 2022;17(1):e0262226. doi: 10.1371/journal.pone.0262226Lampert EJ, Andorra M, Torres-Torres R, et al.Color vision impairment in multiple sclerosis points to retinal ganglion cell damage.J Neurol. 2015;262(11):2491-2497. doi: 10.1007/s00415-015-7876-3Pandya H, Robinson M, Mandal N, Shah V.Hydroxychloroquine retinopathy: A review of imaging.Indian J Ophthalmol. 2015;63(7):570. doi: 10.4103/0301-4738.167120American Academy of Opthalmology.Testing Children for Color Blindess.Fanlo Zarazaga A, Gutiérrez Vásquez J, Pueyo Royo V.Review of the main colour vision clinical assessment tests.Arch Soc Esp Oftalmol (Engl Ed). 2019;94(1):25-32. doi:10.1016/j.oftal.2018.08.006National Eye Institute.Testing for color blindness.Badawy AR, Hassan MU, Elsherif M, Ahmed Z, Yetisen AK, Butt H.Contact lenses for color blindness.Adv Healthcare Mater. 2018;7(12):1800152. doi: 10.1002/adhm.201800152Fliotsos MJ, Zhao J, Pradeep T, Ighani M, Eghrari AO.Testing a popular smartphone application for colour vision assessment in healthy volunteer subjects.Neuro-Ophthalmology. 2021;45(2):99-104. doi: 10.1080/01658107.2020.1817947El-taher FE zahraa, Taha A, Courtney J, Mckeever S.A systematic review of urban navigation systems for visually impaired people.Sensors. 2021;21(9):3103. doi: 10.3390%2Fs21093103
National Library of Medicine MedlinePlus.Color Blindness.
Lamb TD.Why rods and cones?Eye (Lond). 2016;30(2):179-185.doi: 10.1038/eye.2015.236
Barry JA, Mollan S, Burdon MA, Jenkins M, Denniston AK.Development and validation of a questionnaire assessing the quality of life impact of Colour Blindness (CBQoL).BMC Ophthalmol. 2017;17(1):179. doi:10.1186/s12886-017-0579-z
National Eye Institute.Types of color blindness.
National Library of Medicine MedlinePlus.Color vision deficiency frequency.
National Library of Medicine National Center for Biotechnology Information.Achromatopsia.
American Association for Pediatric Ophthalmology.Achromatopsia.
MedlinePlus.Achromatopsia.
https://medlineplus.gov/genetics/condition/achromatopsia/#frequency
Shichi H. Color Blindness. In: Siegel GJ, Agranoff BW, Albers RW, et al., editors. Basic Neurochemistry: Molecular, Cellular and Medical Aspects. 6th edition. Philadelphia: Lippincott-Raven; 1999. Available from:https://www.ncbi.nlm.nih.gov/books/NBK27990/
National Eye Institute.Causes of color blindness.
Niwa Y, Muraki S, Naito F, Minamikawa T, Ohji M.Evaluation of acquired color vision deficiency in glaucoma using the rabin cone contrast test.Invest Ophthalmol Vis Sci. 2014;55(10):6686. doi: 10.1167/iovs.14-14079
Olsen TW, Bottini AR, Mendoza P, Grossniklausk HE.The age-related macular degeneration complex: linking epidemiology and histopathology using the minnesota grading system (The inaugural frederick c. Blodi lecture).Trans Am Ophthalmol Soc. 2015;113:Blodi.
PMID: 27895380
Kim HJ, Ryou JH, Choi KT, Kim SM, Kim JT, Han DH.Deficits in color detection in patients with Alzheimer disease.PLOS ONE. 2022;17(1):e0262226. doi: 10.1371/journal.pone.0262226
Lampert EJ, Andorra M, Torres-Torres R, et al.Color vision impairment in multiple sclerosis points to retinal ganglion cell damage.J Neurol. 2015;262(11):2491-2497. doi: 10.1007/s00415-015-7876-3
Pandya H, Robinson M, Mandal N, Shah V.Hydroxychloroquine retinopathy: A review of imaging.Indian J Ophthalmol. 2015;63(7):570. doi: 10.4103/0301-4738.167120
American Academy of Opthalmology.Testing Children for Color Blindess.
Fanlo Zarazaga A, Gutiérrez Vásquez J, Pueyo Royo V.Review of the main colour vision clinical assessment tests.Arch Soc Esp Oftalmol (Engl Ed). 2019;94(1):25-32. doi:10.1016/j.oftal.2018.08.006
National Eye Institute.Testing for color blindness.
Badawy AR, Hassan MU, Elsherif M, Ahmed Z, Yetisen AK, Butt H.Contact lenses for color blindness.Adv Healthcare Mater. 2018;7(12):1800152. doi: 10.1002/adhm.201800152
Fliotsos MJ, Zhao J, Pradeep T, Ighani M, Eghrari AO.Testing a popular smartphone application for colour vision assessment in healthy volunteer subjects.Neuro-Ophthalmology. 2021;45(2):99-104. doi: 10.1080/01658107.2020.1817947
El-taher FE zahraa, Taha A, Courtney J, Mckeever S.A systematic review of urban navigation systems for visually impaired people.Sensors. 2021;21(9):3103. doi: 10.3390%2Fs21093103
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