Eye condition · Color vision
Color vision deficiency (color blindness)
Color vision deficiency makes some colors hard to tell apart, most often reds and greens. Learn the types, causes, testing and practical tips.
What it is
The retina has three types of cone cells that respond to red, green and blue light. If one type is missing or works differently, some colors look alike. This is color vision deficiency, commonly called color blindness.
Types
- Red-green: the most common type. Protan (red) and deutan (green) forms make reds, greens, browns and oranges hard to tell apart
- Blue-yellow (tritan): rare. Blue and green, and yellow and red, can look alike
- Complete color blindness (monochromacy): very rare, with no color vision and often reduced sharpness and light sensitivity
Causes
Most color vision deficiency is inherited and present from birth. It stays the same through life. Color vision can also change later because of eye diseases such as glaucoma and macular degeneration, optic nerve problems, cataract, and some medicines. A new change should be checked.
How it is diagnosed
Eye doctors use plate tests, arrangement tests and anomaloscopes to identify the type and severity. Our color vision screener gives a quick indication at home.
Living with it
- Use labels, patterns or apps that name colors
- Turn on color-blind settings in games, maps and devices
- Ask teachers to avoid relying on color alone for children’s work
- Check career requirements early, as some jobs need normal color vision
- Tinted lenses help some people distinguish certain colors, but they do not restore normal color vision
Questions people ask
Do color blind people see in black and white?
Almost never. Most people with color vision deficiency see many colors but confuse certain ones, usually reds, greens and browns. Seeing no color at all is very rare.
Can women be color blind?
Yes, but inherited red-green deficiency is much less common in women because it is carried on the X chromosome.