Deuteranomaly
(Green-Weak Color Vision)
Deuteranomaly is partial green-axis weakness, not complete green-blindness. That complete form is deuteranopia. About 5% of men have deuteranomaly.
Free Online Color Blindness Test
Take our free Ishihara color blind test to check for red-green color blindness, deuteranopia, protanopia, and tritanopia. Get instant results with our scientifically-designed 18-plate color vision screening test. No registration required.
- Disable dark mode and blue-light filters (Night Shift, f.lux)
- Set screen brightness to at least 80%
- Ensure you are in a neutral lighting environment
- View screen from a normal reading distance
Deuteranomaly vs Deuteranopia
Deuteranomaly is anomalous trichromacy: three cone types remain, but M-cones are shifted toward L. Deuteranopia is dichromacy: the M channel is missing. A deuteranomaly test online can flag red-green confusion; it cannot replace a Rayleigh match at a clinic.
Use the same 18-plate screen as our full color blind test, then preview UI with the color blind simulator severity slider (partial deuteranopia / deuteranomaly range).
FAQ
What is deuteranomaly?
Deuteranomaly is partial green-axis weakness: M-cones exist but are shifted. It is the most common CVD, affecting about 5% of men.
Deuteranomaly vs deuteranopia — what's the difference?
Deuteranomaly is anomalous trichromacy (three cone types, one shifted). Deuteranopia is dichromacy (no working M-cone channel). Severity is usually milder in deuteranomaly.
How do I take a deuteranomaly test online?
Use the 18-plate Ishihara-style screen on this page. It flags red-green patterns; it cannot measure exact anomalous trichromacy the way a clinic anomaloscope can.