Ishihara Color Blind Test

Not everyone perceives color the same way. Some people have difficulty distinguishing certain colors or shades. This is often called color blindness or, more broadly, color vision deficiency.

There are several main types of color vision deficiency: red–green, blue–yellow, and complete color blindness (monochromatism). The most common is red–green, which affects how a person sees colors in the red/green range.

Color vision deficiency is fairly common. Research suggests it affects about 1 in 12 men and about 1 in 200 women. Overall estimates vary, but it may affect hundreds of millions of people worldwide.

The Ishihara test is one of the most widely used ways to screen for red–green color vision deficiency. It was developed by Shinobu Ishihara in 1917. During the test, you look at a series of plates made up of colored dots. People with typical color vision can typically read the number embedded in each plate, while people with certain red–green deficiencies may find it difficult or impossible to read.

The original Ishihara test includes 38 plates. This online version uses 14 plates for a quicker self-check.

For the most accurate results, don’t wear tinted glasses or sunglasses, and take out any color-tinted contact lenses. Try to view the plates in good, even lighting. Sit at a comfortable distance from your screen — about arm's length. Take your time with each plate; there's no time limit.