What causes Colour blindness ?

The most common cause of color blindness is an inherited problem in the development of one or more of the three sets of color sensing cones in the eye.^[2] Males are more likely to be color blind than females, as the genesresponsible for the most common forms of color blindness are on the X chromosome.^[2]As females have two X chromosomes, a defect in one is typically compensated for by the other, while males only have one X chromosome.^[2] Color blindness can also result from physical or chemical damage to the eye, optic nerve or parts of the brain.^[2]Diagnosis is typically with the Ishihara color test; however, a number of other testing methods also exist.^[2]