Eyes

We have a pair of eyes. They are held in socket of the skull by four rectus muscles and two oblique muscles. These muscles control the movements of the eyes. The wall of the eye ball is composed of an elastic layer. In front this layer is transparent, called the cornea; the rest is opaque, called the sclera. In front, the sclera is covered by a very thin layer called conjunctiva. The next layer lining the inner surface of the sclera is uveal tract. Uveal tract has three parts, the part in front is a circular diaphragm, called iris and aperture of this diaphragm is called pupil. The inner most layer of the eye is nervous layer which is called retina. It is composed of visual nerve endings for reception and transformation of light stimuli.