Color Blindness Test
Quick Ishihara-style screen for red-green colour vision deficiency with a summary at the end.
Written by Golam Rabbani, Founder & Lead Engineer
Plate 1 of 5. What number do you see?
How to use this color blindness test
- View each Ishihara-style plate in good lighting on a colour-calibrated screen if possible.
- Pick the number you can see (or "Nothing") from the multiple-choice answers.
- Continue through all plates — there are five in the screening set.
- Read the final summary for your score, what each plate was designed to detect, and a plain-English interpretation.
- Press Restart to retake the test.
About this color blindness test
The color blindness test is a browser-based colour vision screener built around Ishihara-style "pseudoisochromatic" plates. Each plate shows a large digit drawn in one colour and overlaid with a field of randomly scattered dots in contrasting shades. People with normal colour vision can separate the digit from the background easily, while those with a red-green deficiency find that the digit and its surround blend together or resolve as a completely different number.
The tool works by presenting five plates in sequence. Each plate is engineered for a specific purpose: a control plate that nearly everyone reads correctly, "vanishing" plates where a protan or deutan viewer sees nothing, and "confusion" plates that cause a colour-deficient viewer to read a wrong digit. For example, plate 3 in the set shows "29" in red on a grey background — a viewer with a protan deficiency is likely to read "70" because the red numeral blends into the grey field, while a viewer with normal vision reads the correct answer straight away. After the fifth plate the tool tallies your score, lists each plate's intended reading alongside what you actually answered, and offers a plain-English verdict.
This screener is informational, not diagnostic. Calibrated printed Ishihara plates under standardised lighting, interpreted by an optometrist, are required for a clinical colour vision assessment.
FAQ
- Is this test a real diagnosis?
- No. It is a quick screen built from Ishihara-style plates rendered on whatever monitor or phone you happen to be using. Real colour vision testing uses standardised printed plates and controlled lighting, and an optometrist is the right person to interpret the results.
- Why does the result depend on my screen?
- Every monitor renders colour slightly differently, and uncalibrated phones and laptops can shift hues enough to either reveal or hide a plate that shouldn't be ambiguous. Brightness and ambient light matter too. Treat this as a screening tool, not an instrument.
- What does "red-green colour blindness" mean?
- It is shorthand for protan (reduced red sensitivity) and deutan (reduced green sensitivity) deficiencies, which together cover about 99% of inherited colour vision problems. Both make red and green tones harder to separate.
- How common is colour blindness?
- Roughly 1 in 12 men and 1 in 200 women of Northern European descent have some form of red-green deficiency. Rates differ across populations but the male-female split is universal because the genes involved sit on the X chromosome.
- Can colour blindness be cured?
- Inherited colour vision deficiency is not curable, but tinted glasses (like EnChroma) can shift contrast in helpful ways for some people, and accessibility tooling can compensate in software. Acquired colour vision problems caused by illness or medication sometimes improve when the cause is treated.
- Should I see a doctor about my result?
- If this screen flagged trouble and you have practical concerns (driving, careers that require colour discrimination, sudden change in your vision), see an optometrist or ophthalmologist for a proper test.