The Eye and Vision - How the eye works and how lasik surgery can help your vision

Anatomy of the Eye

Cornea: the clear front window of the eye. The cornea transmits and focuses light into the eye.

Iris: the colored part of the eye. The iris helps regulate the amount of light that enters the eye.

Pupil: the dark center 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.

Lens: the transparent structure inside the eye that focuses light rays onto the retina.

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.

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.

Common Vision Problems

Myopia

You may be familiar with the term myopia, also known as nearsightedness. Myopia is the result of an eyeball which is too long, or a cornea which is too curved. In both cases, light rays entering your eye fall short of the retina, and objects in the distance appear blurred. If you have this condition, you are not alone; more than 70 million people in North America have myopia.

Astigmatism

Astigmatism occurs when your cornea is shaped like a football with two different curvatures. Images appear blurred or ghostlike because light rays are refracted unequally. In extreme cases, images both near and far appear blurred. Many people who have myopia also have astigmatism.

Hyperopia

Hyperopia, or farsightedness, is the opposite of myopia. Here, your eye is too short or your cornea is less curved. Consequently, light rays entering your eye fall behind the retina. This results in blurred vision which is worse at near ranges than far.