There are some standard diagnostic tests that can be used to diagnose color blindness.  The Ishihara color test blends a photo amongst a variety of colored dots.  People with color blindness will not be able to see the photo against the dots of a particular color.  The military uses the Farnsworth Lantern Test which utilizes colored lights to test new recruits.  There is no real cure for color blindness.  Colored lenses in glasses or contacts can help some people to compensate for their color blindness.  Some initial genetic therapy has been tested on animals to improve color perception but this is many years away from any potential in humans.