Cornea: The cornea is a dime-sized clear tissue covering the front of the eye which acts like a camera's aperture & referred to as the ‘front window of the eye'. It provides most of the focusing power when light enters your eye. Light rays pass through the cornea and then through the lens. The lens forms an image on the retina in the back of the eye where the optic nerve is located. Sight is controlled by the optic nerve, the only nerve of vision. This nerve activates the retina to pick up the image in view. The cornea is transparent structure which is composed of 5 layers of tissue. The outer layer (the epithelium) is the eye's protective layer. This layer is made up of highly regenerative cells that can grow back within 3 days, and therefore, allow for fast healing of superficial injuries. Most of the inner layers provide strength to the eye. The corneal grafting, laser vision or R.K correction procedure is performed on this part of the eye. 

Sclera: This is the 'white part' that we see in people's eye. The sclera's purpose is to provide structure, strength and protection to the eye.

Iris: The colored part of the eye mostly brown, black & blue. The iris helps in regulating the amount of light that enters the eye with  contraction or expansion of the muscles of the iris.

Pupil: Acts like a shutter of camera, situated in the middle of the iris. The pupil determines how much light is let into the eye. It changes sizes to accommodate for the amount of light that is available. When you are in a bright environment, the pupil becomes smaller to allow less light through. When it is dark, the pupil expands to allow more light to reach the back of the eye.

Lens: The transparent structure located behind the pupil which helps in focusing light rays over the retina. As people reach their 60’s or 70’s, the lens sometimes becomes cloudy and hard (cataract formation), preventing light from entering the eye

Retina: The nerve layer that lines the back of the eye. The retina senses light and creates impulses that are sent through the optic nerve to the brain, acting as film  to record the light (the photo itself).

Macula: A small area in the retina that contains special light-sensitive cells. The macula allows us to see fine details clearly.

Optic Nerve: The nerve that connects the eye to the brain. The optic nerve carries the impulses formed by the retina to the brain, which interprets them as images.

Vitreous: The clear, jelly-like substance that fills the middle of the eye.

Other eye structures: Support the main activity of sight: Some carry fluids (such as tears and blood) to lubricate or nourish the eye.

Others are muscles: That allow the eye movements. Some protect the eye from injury (such as the eyelids and the epithelium of the cornea). And some are messengers, sending sensory information to the brain (such as the pain-sensing nerves in the cornea and the optic nerve behind the retina).