Albinism is a genetic condition that causes an absence of melanin in the body. This pigment colours hair, skin and eyes – as well as feathers and scales in the animal world. Because albinos don’t make melanin, they can lack pigment in their hair, skin and eyes (oculocutaneous albinism), or just lack eye colour (ocular albinism). More melanin in the iris results in darker eye colour (brown/black), while less melanin results in paler irises (blue/green). Eye colour – and therefore the amount of melanin – determines how much light enters the eye. The more melanin present, the better the retina is shielded from damaging bright light. A total absence of melanin causes an albino’s irises to be pink with red pupils due to light reflected by blood vessels.
Melanin absorbs the Sun’s harmful ultraviolet rays. Normally, when the skin is exposed to sunlight, more melanin is produced to absorb UV radiation and, in turn, tan the skin. Someone affected by albinism, therefore, is prone to sunburn and more susceptible to cancer so they must be careful to avoid high exposure to the Sun.