What is colour blindness?

Colour blindness (colour vision deficiency) is a reduced ability to distinguish between certain colours. The most common type is red-green colour blindness, which affects approximately 8% of men and 0.5% of women of Northern European descent. It is usually inherited and caused by an absence or malfunction of colour-sensitive cone cells in the retina.

Is this test a medical diagnosis?

No. This is a screening tool only. Online tests cannot replicate the controlled lighting and calibrated colour conditions of a clinical Ishihara test. If this test suggests colour vision deficiency, consult an optometrist or ophthalmologist for a proper clinical assessment using standardised Ishihara plates or the Farnsworth D-15 test.

What are the types of colour blindness?

The main types are: Protanopia (no red cones, red appears dark), Deuteranopia (no green cones, most common), Protanomaly (reduced red sensitivity), Deuteranomaly (reduced green sensitivity, most common form overall), Tritanopia (no blue cones, very rare), and Achromatopsia (total colour blindness, extremely rare). Red-green deficiency accounts for approximately 99% of all colour vision deficiency.

Can colour blindness be cured?

There is currently no cure for inherited colour blindness. However, special EnChroma or Pilestone glasses can enhance colour perception for some people with red-green deficiency. Gene therapy research is ongoing. Acquired colour vision deficiency (from disease, medication, or aging) may sometimes be treatable by addressing the underlying cause.

Does screen brightness affect the test?

Yes. For the most accurate results, set your screen brightness to maximum, use your screen in a well-lit room (avoid direct sunlight on the screen), and ensure your display's colour settings are set to default (no night mode, blue light filter, or colour correction). Different screens display colours differently, which is why this is a screening tool, not a clinical test.

Colour Blindness Test | Free Online Ishihara-Style Test

Colour Blindness Test

Test your colour vision with eight Ishihara-style dot plates. Each plate displays a number hidden within a pattern of coloured dots. Select the number you see, or choose "I can't see a number" if the pattern is unclear. Results are provided at the end with an explanation of what they suggest about your colour vision.

Types of Colour Vision Deficiency

Type	Affects	Prevalence
Deuteranomaly	Reduced green sensitivity	~5% of men
Protanomaly	Reduced red sensitivity	~1% of men
Deuteranopia	No green cones	~1% of men
Protanopia	No red cones	~1% of men
Tritanopia	No blue cones	Very rare
Achromatopsia	Total colour blindness	~1 in 30,000

Type

Affects

Prevalence

Deuteranomaly

Reduced green sensitivity

~5% of men

Protanomaly

Reduced red sensitivity

~1% of men

Deuteranopia

No green cones

~1% of men

Protanopia

No red cones

~1% of men

Tritanopia

No blue cones

Very rare

Achromatopsia

Total colour blindness

~1 in 30,000

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This screening tool generates approximate Ishihara-style plates using Canvas rendering. Screen colour accuracy varies by device. This is not a substitute for a clinical colour vision assessment by a qualified eye care professional.

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Colour Blindness Test

Your Result

Types of Colour Vision Deficiency

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