Color blindness refers to a group of conditions that result in a person not being able to see the full range of colors. In most cases color blindness is an inherited condition. Disease or injury can also cause damage to the retina or optic nerve, which may result in loss of color recognition.
Inherited Color Deficiencies
- Red-green color blindness: most common color deficiency and primarily found in men.
- Blue-yellow color blindness: very rare and not a sex-linked inherited trait.
- Achromatopsia: complete absence of color vision and very rare.
Disease-Specific Causes of Color Vision Loss
- Macular degeneration
- Alzheimer's disease
- Parkinson's disease
- Multiple sclerosis
- Chronic alcoholism
- Sickle cell anemia
- Chemical exposure
While very few women face color vision challenges, approximately 1 out of every 10 men experiences some form of color blindness. Research suggests approximately 5% of the population experience some challenge in perceiving color.
What’s more, the number of adults over the age of 65 is expected to climb over the coming decades. In fact, nearly 1 in 4 people in South Dakota is projected to be age 65 or older.
Age related changes to the eye may impact how a person perceives color. For example, over time the lens of the eye yellows, making yellow, blue, and green more problematic than when the individual was younger. In addition, a clouding of the lens called cataracts is more common in adults. While cataracts may not rob a person of color vision, they do dull colors and blur vision.
Old age is not an illness or disease, however, aging is associated with a greater susceptibility to chronic illness or disability that may either impact color vision perception or result in medication consumption that has a side effect of damaging color vision. For example, the drug hydroxychloroquine used to treat rheumatoid arthritis can cause color blindness.
For the reasons described above we should account for color deficient vision when we make design decisions. Knowing what colors work well for people with color deficient vision can be challenging. This infographic contains 4 tips to increase readability in web design and printed materials.
- Effective Colour Contrast
- WebAIM: Color Contrast Checker
- U.S. National Library of Medicine: Color blindness
- Genetics Home Reference: Color vision deficiency
- Color Blindness Awareness: Living With Color Vision Deficiency
- American Optometric Association: Color Vision Deficiency
- Adult vision: 41 to 60 years of age
- Web Accessibility 101 Video Series: Effective Color Contrast