App is a easiest way to determine the color blindness.
Dr Shinobu Ishihara introduced in 1917almost 100 years agothe most well known color blindness test. Each of his tests consists of a set of colored dotted plates, each of them showing either a number or a path. Since then this is the most widely used color vision deficiency test and still used by most optometrists and ophthalmologists all around the world.
There are other color blindness tests available, but none of them is as famous as the Ishihara plates. It is also well known, that even people with normal color vision sometimes struggle with this test. But nevertheless this plates are still in use in the absence of any better and still affordable color vision test.