Inability to distinguish one or more colours. The human retina contains three types of cone cells that absorb light in different parts of the spectrum. Absence of these types causes colour blindness to red, green, and blue. Colour blindness is a sex-linked recessive trait (see recessiveness) 20 times more common in men than in women
an inability to distinguish between certain colors such as red and green (most common form - colors would appear as yellow) This condition is an inherited trait that occurs almost exclusively in males, but the recessive gene that causes the condition is carried by the female