The HRR test (Hardy-Rand-Rittler) is a pseudo-isochromatic plate test that uses symbols — a circle, a triangle, and a cross — hidden in colored dots instead of numbers. Unlike the Ishihara test, which checks red-green only, the HRR screens both red-green (protan / deutan) AND blue-yellow (tritan), and grades the degree (mild, moderate, or strong). This free online version screens all three cone axes in about a minute with freshly generated plates, then estimates your type and severity. Screening is reliable on a normal screen; type and degree are estimates, and blue-yellow is the least reliable on an uncalibrated display. It is a self-check, not a diagnosis.
Symbol plates · red-green + blue-yellow
HRR Test
Find symbols hidden in colored dots to screen red-green and blue-yellow vision. Results are estimates on an uncalibrated screen.
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Also available in: Español · Português · Italiano
How the HRR test works
1. Find the symbol
Each plate hides a symbol — a circle, triangle, or cross — in a field of brightness-matched colored dots. People with typical color vision see it easily; a color vision deficiency can make it hard to find or look like a different symbol. Plates probe red, green, and blue cone axes in turn.
2. Tap the symbol
Tap the symbol you see (or 'Nothing' if none stands out). Don't strain — answer with the first thing you see. The plates start clear and get fainter; the faintest plate you can still read on each axis sets your degree.
3. Type & degree
We tally misses per axis. More misses on red than green suggests protan; more on green suggests deutan; misses on the blue-yellow plates suggest tritan. How faint a plate you can still read estimates the degree. Because your screen isn't calibrated, treat type and degree as estimates, not a diagnosis.
What the HRR test can and cannot tell you
Reliable screening. Whether a color vision deficiency is present — dependable on a normal screen.
Checks blue-yellow too. HRR grades tritan as well as red-green — unlike the Ishihara test.
Estimates the type and degree. Protan, deutan, or tritan. Mild cases can be a close call, and blue-yellow is the least reliable on an uncalibrated screen.
Using it for anything official? For licensing, driving, or medical decisions, confirm with an eye-care professional.
This is a free screening and self-assessment tool, not a medical diagnosis. Results are affected by your screen, its color settings, and room lighting.
Want to classify the type more carefully?
The HRR screens and grades. To sort the arrangement of colors along your confusion axis, try the Farnsworth D-15 test, or see how all the tests compare on more color vision tests.
HRR test — frequently asked questions
- What is the HRR color vision test?
- The Hardy-Rand-Rittler (HRR) test is a pseudo-isochromatic plate test that uses symbols (circle, triangle, cross) instead of numbers. The full clinical version both screens for and classifies color vision deficiency — including blue-yellow — and grades its degree, which is why it is used diagnostically as well as for screening.
- How is the HRR test different from the Ishihara test?
- Both use brightness-matched colored-dot plates. The Ishihara test screens red-green only and uses hidden numbers. The HRR is language-free (symbols, not numbers), screens blue-yellow as well as red-green, and grades the degree (mild / moderate / strong), so it works for children and gives a fuller picture.
- Does the HRR test detect blue-yellow color blindness?
- Yes. A key advantage of the HRR over the Ishihara test is that it includes blue-yellow (tritan) plates, so it can flag blue-yellow deficiency as well as red-green. On an uncalibrated screen, blue-yellow results are the least reliable, so treat any blue-yellow finding with caution and confirm it with an eye-care professional.
- Is this online HRR test accurate?
- For screening — whether a color vision deficiency is likely present — an online HRR on a normal screen agrees closely with clinical screening. Identifying the exact type and degree is less reliable on an uncalibrated screen and should be treated as an estimate, especially for blue-yellow.
- How many HRR plates are there?
- The full clinical HRR (4th edition) has 24 plates — demonstration plates, six screening plates, and diagnostic plates that grade type and severity. This online version uses a shorter generated book that screens all three cone axes and estimates type and degree while staying about a minute long.
- Can I use the HRR test for a driving licence or job?
- Use it for self-screening only. For licensing, aviation, or any medical or employment decision, confirm your result with an eye-care professional using clinical equipment (such as an anomaloscope, the printed HRR, or a CAD test).