Color Blindness Test
Screen your color vision with our pseudo-Ishihara plate test. This browser-based test presents a series of plates designed to detect red-green color vision deficiencies including protanopia (L-cone deficiency) and deuteranopia (M-cone deficiency).
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Screening only — pseudo-Ishihara plates rendered as SVG dot matrices. Cannot replace a clinical Ishihara test; results depend on display calibration and ambient lighting.
Frequently Asked Questions
What does the color blindness test detect?
The test screens for red-green color vision deficiencies by presenting pseudo-Ishihara plates — patterns of colored dots that hide a digit visible only to people with normal color vision. It can indicate protanopia (red-blindness, caused by absent L-cones), deuteranopia (green-blindness, caused by absent M-cones), or a possible red-green deficiency when results are mixed.
Is this test a clinical diagnosis?
No. This is a screening tool, not a clinical diagnosis. A positive result indicates you may have a color vision deficiency, but only a qualified eye care professional can confirm a diagnosis using standardized Ishihara plates under controlled lighting. Use this test as an initial self-check.
What is the difference between protanopia and deuteranopia?
Both are red-green color deficiencies. Protanopia is caused by missing or non-functional L-cones (long-wavelength cones sensitive to red light), making reds appear darker. Deuteranopia is caused by missing or non-functional M-cones (medium-wavelength cones sensitive to green light). This screening test cannot reliably distinguish between the two — the data model preserves both for future plates.
Why can't the test detect tritanopia (blue-yellow deficiency)?
Tritanopia (blue-yellow blindness) is rare and caused by absent S-cones. The pseudo-Ishihara plates in this test are tuned for red-green luminance contrast and cannot reliably screen for tritanopia. If you suspect blue-yellow deficiency, consult an eye care professional for a comprehensive exam.
How accurate is an online Ishihara test?
Accuracy depends on your display, ambient lighting, and viewing conditions. For best results: use a calibrated sRGB display in a well-lit room, avoid blue-light filters or night mode, and sit at a comfortable reading distance. Online tests are less reliable than clinical tests but are useful for initial screening.
What should I do if the test suggests a color vision deficiency?
Don't panic — most color vision deficiencies are mild and don't affect daily life. If the result impacts your work (e.g., design, electrical work, aviation), schedule an appointment with an optometrist or ophthalmologist for a clinical Ishihara test or an anomaloscope exam, which can precisely classify the type and severity.