Specialty Vision · Vision Simulator
Deuteranopia Simulator — Red-Green Colour Blindness
Deuteranopia is a red-green colour vision deficiency caused by missing green-sensitive cones — the most common type — making reds, greens, browns and oranges easy to confuse.
Overview
Normal colour vision uses three cone types (red, green, blue). In deuteranopia the green-sensitive cones are absent, so the brain can't separate certain reds and greens — they collapse toward similar muddy yellows and browns. It's inherited on the X chromosome, which is why it's far more common in men, and it's lifelong and stable. People with deuteranopia see a full, bright world; they simply confuse particular shades. A milder version, where the green cones work but are shifted, is called deuteranomaly.
Symptoms
- Confusing reds, greens, browns and oranges
- Trouble with traffic lights, ripe fruit, and red text on a green background
- Difficulty with colour-coded charts, maps and status lights
- Often unaware of it until a colour-vision test
Causes
- Inherited absence of the green-sensitive (M) cone photopigment, carried on the X chromosome
- Far more common in men (about 1 in 12) than women (about 1 in 200)
Treatment
Deuteranopia can't be cured and rarely needs treatment. Special tinted glasses or contact lenses help some people separate confusable colours (they don't restore normal colour vision), and using brightness, position and labels rather than colour alone makes daily life easier. A sudden change in colour vision, by contrast, should be checked.
When to see an eye doctor
Inherited deuteranopia is stable and not dangerous — usually it only needs a one-time diagnosis, useful for school and certain careers. See an eye doctor promptly if your colour vision changes suddenly or differs between your two eyes, which can signal acquired eye disease.
Seek urgent care for:
- A sudden change in colour perception
- Colour vision worse in one eye than the other
- Colour change together with vision loss or eye pain
Frequently asked questions
What is deuteranopia?
It's the most common red-green colour vision deficiency, caused by missing green-sensitive cones, so reds and greens look similar. People with it see a full, colourful world but confuse certain shades — they don't see in black and white.
How common is deuteranopia?
Red-green deficiency (deuteranopia and the related deuteranomaly and protan types) affects roughly 1 in 12 men and 1 in 200 women, because the genes are carried on the X chromosome.
What's the difference between deuteranopia and deuteranomaly?
Deuteranopia means the green-sensitive cones are absent; deuteranomaly means they work but are shifted, giving a milder red-green confusion. The simulator lets you compare the types.
Can deuteranopia be corrected?
It can't be cured. Tinted 'colour-correcting' glasses help some people tell confusable colours apart, but they don't create normal colour vision. Most people adapt well using brightness, position and labels.
Sources
- What Is Color Blindness? — American Academy of Ophthalmology
- Color Blindness — National Eye Institute