How the Eye Works
The human eye works much like a camera. Light enters the eye and is focused on the retina, like the film of a camera. The cornea, the clear front window of the eye, and the natural lens inside the eye serve as the lenses that focus light. The iris is the colored part of the eye that has a central opening called the pupil. The pupil can change sizes to regulate the amount of light entering the eye.
Once the light is focused on the macula, the central area of the retina used for fine-detailed vision, an electrical impulse is generated, which travels through the optic nerve to the brain. The brain then deciphers the visual information and the image is perceived. And just like poorly-focused photographs will result in blurry prints, your vision will be blurred if any part of your visual system is impaired. Refractive error is the most common cause of blurred vision and occurs when light rays do not focus on the retina. Refractive errors include nearsightedness (myopia), farsightedness (hyperopia), and astigmatism. Refractive errors can be corrected with spectacles and contact lenses as well as laser and implant vision correction.
The area between the natural lens and retina is filled with a jello-like substance called the vitreous humor. The sclera is the white outer wall of the eye, which is covered by a thin skin layer called the conjunctiva.