Color vision test
An online colour vision screening built on self-drawn SVG dot plates: read four number plates, and preview them through protanopia, deuteranopia and tritanopia simulation (Viénot/Brettel 1999 matrices). For reference only — it is not a medical test.
Runs in your browserEvery computation happens in your browser — your data never leaves this device.
Plate
The dot plates are drawn from scratch by this tool (no copyrighted colour-vision test images are used). The simulation uses the linear-sRGB matrices from Viénot, Brettel & Mollon 1999.
Result
Read the number on each plate in order; submitting moves you to the next plate.
What this tool does
- Screen yourself before a medical, driving or job check-up: read the four plates in order and get an immediate reading.
- Understand what colour blindness looks like: switch between protanopia, deuteranopia and tritanopia and the same plate is recoloured instantly.
- Explain colour vision to children — traffic lights or metro maps for someone with red/green deficiency is far easier to show than to describe.
- Sanity-check a design palette: flip it into each dichromat simulation and see whether the key information still stands out.
Example
Input
Answer the four plates in order: 7, 3, 5, 2
Output
4 / 4 correct, accuracy 100%, reading “All four plates read correctly, no obvious issue”
The four sample plates are 7, 3, 5 and 2. Each plate is generated from a fixed random seed, so the dot pattern is identical on every render.
Frequently asked questions
Are these the original Ishihara plates?
No. The Ishihara plates are copyrighted, so every dot pattern here is drawn by the tool: digits come from a built-in 5×7 bitmap font, and each dot takes the figure or background colour depending on whether it falls inside the glyph, with a share of confusion dots mixed in. The look is similar, the artwork is generated.
Which algorithm drives the simulation?
The linear-sRGB matrices published by Viénot, Brettel & Mollon (1999): sRGB is linearised, multiplied by the protan/deutan/tritan matrix, then gamma-encoded back. These are true dichromat projections, so applying them twice changes nothing (idempotent) and white or grey stay put.
How accurate is the result?
Treat it as a rough self-check. Screen calibration, brightness, ambient light and fatigue all affect reading, and a real examination also separates dichromacy from anomalous trichromacy across many more hues. If you misread two or more plates, book a proper eye test instead of drawing conclusions here.
Why can I still read the number after switching the simulation?
The simulation shows the colours a dichromat would see, but the lightness contrast of the plate is preserved, so a typical viewer can still read it. What matters is that colours distinguished by hue alone collapse into a brightness difference.
Are my answers stored?
No. Answering and scoring happen in browser memory, the plates are generated locally, and the page makes no network requests — a refresh clears everything.
Keywords：color vision testcolor blind testishihara style plateprotanopiadeuteranopiatritanopia色觉测试色盲色弱筛查色点阵色觉模拟