The ophthalmologist will do a simple test to know whether a person is affected with color vision blindness. The test involves showing a pattern that contains multi-colored dots. If the person does not have color vision blindness, he or she will be able to see the numbers and shapes in the dots. If the person has color vision blindness, he or she will have a hard time finding the shape or number in the pattern. The affected person may not be able to see anything in the pattern.