Colour Blindness Test
This free online screening test checks how well you can distinguish colours, focusing on red-green colour vision deficiency, the type that affects around 8% of men and 0.5% of women of Northern European descent. You work through eight Ishihara-style dot plates shown one at a time, each generated from clusters of randomly coloured dots that hide a number inside a different-coloured background. For every plate you select the number you see from the multiple-choice buttons provided, or choose "Nothing" if no number is visible, then move on using the next and previous buttons while a row of progress dots tracks your answers. Once all eight plates are done, the calculator returns your score out of eight with a plain-English interpretation: seven or eight correct suggests normal colour vision, four to six points to a possible mild deficiency such as deuteranomaly, and below four suggests a more significant deficiency. Before you start, set your screen to maximum brightness in a well-lit room and turn off night mode or any blue light filter, because screen calibration and lighting change how the dot colours appear. You can retake the test as often as you like. This is a screening tool only, not a medical diagnosis, so if your result suggests a deficiency, see an optometrist or ophthalmologist for a proper clinical assessment using calibrated Ishihara plates or the Farnsworth D-15 test.
