This diagram of a human eye and the following definitions will be useful as you review the materials in this Web site.

Cornea : It is clear protective coating on the front of the eye that allows light to pass through it without distortion. The lens of the eye focuses the images transmitted through the cornea to the retina. These images are then transferred via the optic nerve to the brain where sight is displayed.

Conjunctiva : It is the clear covering of the white part of the eye the sclera.

Sclera : this is the white part of the eye.

Lens : In our eyes the lens lies directly behind the pupil in the sac-like capsule. It focuses images onto the retina which acts as the film that records the picture . Then the picture transmitted by the optic nerve to the brain.

Pupil : The dark center of the iris is the pupil. It decides how much light is needed for the eye to see properly.

Aqueous : The aqueous is a clear, watery solution in the anterior and posterior chambers

Retina : It is the light sensitive part of the eye. It has one major artery and one major vein which is known as central retinal vein.

Uvea : It is the middle section of eye. It consist three parts the iris , the ciliary body and the choroids.

Ciliary body : It is an unseen part of the iris, and these together with the ora serrata form the uveal tract. 

Iris : The iris gives our eyes color and it functions like the aperture on a camera, enlarging in dim light and contracting in bright light. The aperture itself is known as the pupil.

Macula : It is the part of the eye that contains special light sensitive cells which allows us to see fine details clearly.

Vitreous : It is the clear jelly-like substance that fills the middle part of the eye.

Optic Nerve : This is the pathway that connects eye to the brain.

Eyelids : They maintain vision by keeping moisture inside and foreign particles outside of the eyes.

Orbit : It is the bony housing in which the eyeball situated .