Exactly how is a person's eye color determined? It depends on the amount, type and distribution of melanin, or pigment, in ...

Pupillometry measures the size and reactivity of the pupil, the dark circle at the eye’s centre through which light enters. Typically, the pupil contracts and dilates depending on the amount of ...

Medically reviewed by Christine L. Larsen, MD Eye color change surgery is used to change the colored part of the eye, called ...

(Interestingly, different animals have different color tapeta ... which is why so many nocturnal eyes have slit pupils. These apertures can be vertical, horizontal, or diagonal.