Eagle eye to the tear duct”. Eagle tears moisten the eyes and contain the chemical lysozyme which protects against salt water and also destroys bacteria, thus preventing eye infections. The nictitating membrane acts a sweeping wiper across the eye. The eagle iris is a pale yellow color, much lighter than human eyes. Both eagles and humans have a white area called the sclera, but in the case of eagles, it is hidden below the eyelid. Eyelid openings are oval-shaped in humans, while they are round in the case of birds' eyes. Most eagles have excellent vision. Generally, eagles do not suffer from
Eye color therefore should protect their eyes from direct exposure to sunlight. Wilson's disease involves a mutation of the gene coding for the enzyme ATPase7B, which prevents copper within the liver from entering the Golgi apparatus in cells. Instead, the copper accumulates in the liver and in other tissues, including the iris of the eye. This results in the formation of Kayser–Fleischer rings, which are dark rings that encircle the periphery of the iris. Eye color outside of the iris may also be symptomatic of disease. Yellowing of the sclera (the "whites of the eyes") is associated with jaundice, and may be