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
Book of the Ten Treatises of the Eye means for medieval ophthalmologists in the West to come into contact with the work of Galen. There are four essential doctrines that shape Hunayn's dissertation on vision and the anatomy of the eye: Hunayn relies on these principles to build up his conception of vision, which incorporates the anatomy of the eye in a way that makes discussion of one without the other unproductive. The structure of the eye is presented as a hierarchy, starting first with the part that is most directly responsible for sight, and working down towards the parts which exists only to facilitate this function. The