Colour Blindness Explained
What colour vision deficiency is, the common types, and how it is usually identified.
By Lumora Editorial Team · September 17, 2026 · 5 min read
"Colour blindness" is a common phrase, but most people with a colour vision deficiency see colours — they just perceive some colours differently or find certain shades harder to tell apart. This article is general education, not medical advice.
How colour vision works
The retina contains cone cells that respond to different ranges of light: roughly long (red), medium (green) and short (blue) wavelengths. Your brain compares the signals from these cones to produce the sense of colour. If one type of cone works differently or is missing, some colours become harder to distinguish.
Common types
- Red–green deficiencies are the most common. They include reduced sensitivity to red light (protan types) or green light (deutan types). Reds, greens, browns and oranges may look similar.
- Blue–yellow deficiencies (tritan types) are much rarer and affect blues, greens and yellows.
- Complete colour blindness (seeing only shades of gray) is very rare.
Inherited red–green deficiencies are far more common in people assigned male at birth, because the relevant genes are carried on the X chromosome.
How it is identified
Eye-care professionals often use plates of coloured dots containing numbers or paths, which are easy to see with typical colour vision and harder with certain deficiencies. More detailed tests can identify type and severity. Online versions are interesting but depend heavily on screen calibration, so they are not a diagnosis.
Everyday life
Many people with colour vision deficiency do not notice it until tested. Small adaptations can help:
- Labelling clothes or using apps that identify colours.
- Relying on position as well as colour (for example, traffic lights).
- Choosing high-contrast settings on devices.
What about special glasses?
Some tinted glasses are marketed to people with colour vision deficiency. They may change contrast between certain colours for some wearers, but they do not restore typical colour vision. Results vary widely, so it is worth discussing expectations with an eye-care professional.
Choosing frames
If colour matching is tricky, classic tones such as black, tortoise and crystal pair easily with most outfits. Our frame colour guide has more ideas.
This article is general information and not a substitute for advice from a licensed eye-care professional.
