Color blindness results from an absence of color-sensitive pigment in the cone cells of the retina, the nerve layer at the back of the eye that converts light into nerve signals that are sent to the brain. A person with color blindness has trouble seeing red, green, blue, or mixtures of these colors.
Most color vision problems are inherited and are present at birth. Other color vision problems, called acquired colored vision problems, are caused by aging, disease, injury to the eye, optic nerve problems, or a side effect of medicines. Inherited color blindness is more common than acquired color blindness and affects males far more often than females.
Inherited color vision problems cannot be treated or corrected. Some acquired color vision problems can be treated, depending on the cause.
WebMD Medical Reference from Healthwise