Normal colour vision (trichromacy) refers to vision that uses all three types of light cones. People with defected trichromatic vision will be colour blind to some extent and these conditions are called anomalous trichromacy. Three types anomalous trichromacy ( one type of cone perceives light slightly) :
1. Protanomaly – phenotype: reduced sensitivity to red light
2. Deuteranomaly - phenotype: reduced sensitivity to green light
3. Tritanomaly – phenotype: reduced sensitivity to blue
People can also have color blindess as the result of mutation, when loss of function of one cone occurs. This condition is called dichromacy. If there is complete color blindness or monochromacy, the person can’t distinguish any color from grey.
Color blindness is an inherited genetic disorder resulted from mutations on the X chromosome.
