Protanomaly
Test Online
Protanomaly is partial red-axis weakness—less severe than protanopia (complete red-blindness). Free 18-plate screening in under 2 minutes.
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
What Is Protanomaly?
Protanomaly is a form of red-green color vision deficiency where long-wavelength (L) cones are present but do not function normally. The red channel is weakened rather than absent, so colors shift along the red-green axis but some discrimination remains.
Protanomaly vs Protanopia
Protanopia vs protanomaly: protanopes lack functional red cones entirely—reds appear very dark or black. Protanomalous vision retains a shifted red channel, so severity varies from mild confusion to moderate difficulty with red-green tasks. Our protanomaly test uses the same Ishihara screening as a full color blind test.
Everyday Challenges
- Difficulty distinguishing ripe vs unripe fruit
- Red and green traffic lights may look similar in some lighting
- Red error states in UI may be less noticeable than for protanopes
Design & Simulation
Preview UI under partial red weakness with our color blind simulator (severity slider) or compare all CVD types on the color blindness simulation page.