6) Color Blindness
Our retinal rods are responsible for vision during night whereas retinal cones are responsible for vision during day. Color blindness attributed to x-linked recessive gene characterized by inability to identify all the colors in a visible spectrum and differentiate the colors, as the retinal cones are not properly developed.
Color blindness may be a genetic disorder but injury to a particular cranial nerve i.e., optic nerve will also result in color blindness. As x linked recessive gene is involved, men are more vulnerable to this condition than women. Red-green color blindness test or ishihara test is the best tool to diagnose color blindness.