Q. Why do albino humans and animals have red eyes?
A. Eyes are not actually red or pink in humans and animals with albinism. Instead, the absence or shortage of pigment in the eye exposes underlying blood vessels.
In humans, a condition called oculocutaneous albinism reduces pigmentation of skin, hair and eyes. Both the iris and the tissue coating the retina contain very little coloration, and so an observer can see through the translucent eye to the network of blood vessels under the retina.
The condition, which results from genetic anomalies that block or limit an enzyme needed to produce the pigment melanin, is linked to several vision flaws and sensitivity to light. Another form of albinism, called ocular albinism, is less common and affects only the eyes.
Albino animals include the familiar white rabbit. Although there are albino cats, the blue-eyed Siamese is not a true albino; its fur gains color under the proper temperature conditions.