Screening tool · 3 min
Online Colour Vision Test (Ishihara-Style)
12-plate Ishihara screening for red-green colour deficiency.
What this test measures
Whether the cone cells in your retina respond normally to red and green wavelengths of light. The 12 Ishihara-style plates use vanishing, transformation and hidden-digit patterns to detect red-green colour vision deficiency.
Why it matters
Colour vision is essential for tasks like reading traffic lights, identifying medications, electrical work, design and aviation. Most colour blindness is inherited and lifelong, but new changes in colour perception can also signal eye or neurological disease.
Who may benefit
Anyone curious about their colour perception, parents checking children before school, and people in colour-critical careers. Dr. Roxanna Gangi can perform a clinical colour vision test if results are unclear.
Disclaimer: This tool is for educational purposes only and does not replace a professional eye examination. Screen brightness, calibration, lighting and viewing distance all influence results. For an accurate assessment, request a comprehensive exam with Dr. Roxanna Gangi, your trusted Optometrist in Toronto and York Region.
How to take this test
- Use a well-lit room and natural daylight if possible.
- Sit about 60–75 cm from the screen.
- Look at each plate and type the number you see.
- If you can't see any number, click Can't see / skip.
- Don't overthink it — answer within a few seconds.
Take the test
Frequently asked questions
Want a real, in-person assessment?
Online tools are a great starting point, but a comprehensive eye exam with Dr. Roxanna Gangi can detect conditions that screen-based tests cannot — including glaucoma, diabetic retinopathy, and early macular changes.