What is melanin?
Melanin is a chemical pigment that occurs in various body tissues and is responsible for giving the skin its colour among other things.
Its main role in the body is protective. In the skin it absorbs ultraviolet light, which is an invisible part of sunlight that causes sunburn and can contribute to skin cancer.
In the eyes the role of melanin isn't fully understood, however melanin is found in the retina, particularly in the fovea, the area which receives the sharpest light images.