How The Eye Works
The Process of the EyeView Video
Of our five senses, many of us value and depend on our vision most of all. Our vision allows us to interact with and respond to the world around us in unique and important ways.
The eye is a remarkable organ. The individual components of the eye work in a manner similar to a traditional camera. Each part plays a vital role in providing clear vision:
First:Light coming from objects passes through the cornea, a clear protective shield in the front of your eye.
Next: The light goes through the pupil, an adjustable opening (often called aperture) in the center of the iris, or colored part of your eye.
Then: Behind the pupil is the lens. Muscles inside your eye control the shape of the lens, focusing it (as a camera lens does) to view objects at different distances.
Last: The light rays pass through the dark chamber of your eyeball to the retina (in the camera, this is the film) at the back of your eye. The retina contains nerve cells that signal to your brain through the optic nerve. As your brain receives the messages, you see the object before you.
Refractive ErrorsView Video
If light rays do not focus properly on your retina, you have a refractive error.
If you are near-sighted, light rays coming into your eye focus in front of the retina, causing blurry vision. Often, this results when the cornea is too steeply curved.
If you are far-sighted, light rays focus behind the retina, which also results in blurry vision. This results most often when the cornea is too flat.
In Astigmatism, the cornea has an irregular curvature that produces two different focal points.
Presbyopia is simply the inability of the eye to read close up, due to aging of the natural lens of the eye.