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Colour blindness is a vision problem that means you have trouble seeing shades of red, green, or blue or a mix of these colours. It happens when there's a problem with some of the cells found in the layer of nerves (retina) at the back of the eye.
Almost always, the problem runs in families and is something you are born with. It's found more often in males than in females. Colour blindness that you are born with can't be treated or corrected. But you can learn ways to adapt to being colour blind.
Most colour vision problems are inherited (genetic) and are present at birth.
People usually have three types of cone cells in the eye. Each type senses either red, green, or blue light. You see colour when your cone cells sense different amounts of these three basic colours. The highest concentration of cone cells are found in the macula, which is the central part of the retina.
Inherited colour blindness happens when you don't have one of these types of cone cells or they don't work right. You may not see one of these three basic colours, or you may see a different shade of that colour or a different colour. This type of colour vision problem doesn't change over time.
A colour vision problem isn't always inherited. In some cases, a person can have an acquired colour vision problem. This can be caused by:
The symptoms of colour vision problems vary.
Tests can measure how well you recognize different colours.
Because a colour vision problem can have a big impact on a person's life, it is important to detect the problem as early as possible. In children, colour vision problems can affect learning abilities and reading development. And colour vision problems may limit career choices that require you to tell colours apart. The Canadian Paediatric Society recommends eye examinations at all newborn and routine checkups. Vision screening is recommended for all children at least once before entering school, preferably between the ages of 3 and 5. footnote 1
Inherited colour vision problems cannot be treated or corrected.
For the most common type of colour blindness—red-green colour deficiency—no treatment is needed, because you function normally. You may not be aware that you do not see colours the way they are seen by others.
Some acquired colour vision problems can be treated, depending on the cause. For example, if a cataract is causing a problem with colour vision, surgery to remove the cataract may restore normal colour vision.
You can find ways to help make up for a colour vision problem, such as:
CitationsCommunity Paediatrics Committee, Canadian Paediatric Society (2009, reaffirmed 2018). Vision screening in infants, children and youth. Paediatrics and Child Health, 14(4): 246–248. http://www.cps.ca/en/documents/position/children-vision-screening. Accessed April 12, 2021.
Current as of: October 12, 2022
Author: Healthwise StaffMedical Review: Kathleen Romito MD - Family MedicineMartin J. Gabica MD - Family MedicineAdam Husney MD - Family MedicineE. Gregory Thompson MD - Internal MedicineChristopher J. Rudnisky MD, MPH, FRCSC - Ophthalmology
Current as of: October 12, 2022
Author: Healthwise Staff
Medical Review:Kathleen Romito MD - Family Medicine & Martin J. Gabica MD - Family Medicine & Adam Husney MD - Family Medicine & E. Gregory Thompson MD - Internal Medicine & Christopher J. Rudnisky MD, MPH, FRCSC - Ophthalmology
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