How the Eye Works

    CHICAGO, IL, April 30, 2010 /24-7PressRelease/ -- Nothing is more precious than your eyesight. Maintaining good sight and healthy eyes is the responsibility of an individual and his or her ophthalmologist. One look at the complexity of the eye's structure is enough to understand the need to choose a knowledgeable and professional eye doctor to safeguard your precious sight.

Eye Structures For Vision

The eye's components work together to transmit the image we see to the brain's vision center. Structures directly involved in vision are:

- The cornea - clear front covering over the eye which allows image-carrying light to enter the eye and which bends it towards a focus on the retina;
- The lens - suspended behind the colored iris which further bends the light and allows it to pass through to the retina;
- The retina - the inside back surface of the eyeball - which is filled with light-sensitive cells. They convert the image data to electrical data for the brain to interpret;
- The optic nerve - a bundle of tiny nerve fibers that run from the retinal cells to converge and travel to the brain, carrying the electrical data

Sight and Light

Clear sight depends on the presence of light and on the eye's cornea and lens remaining transparent so the light can travel through to the retina. There are two types of retinal cell. Cones give us our central vision in bright light with color perception. Rods give us our night vision and do not pick up color.

The eye's pupil (black circle in the middle of the colored iris) is like a camera aperture. It widens or narrows according to how bright the ambient light is, and thus it controls how much light enters the eye. The iris in each is the muscle that determines the size of your pupils.

Vision Aberrations

Vision problems correctable by LASIK are caused by corneal curvature that is:
1. Too steep, causing myopia (near sightedness);
2. Too flat, causing hyperopia (farsightedness); or
3. Oval instead of spherical, causing astigmatism.

These three vision problems are known as the Lower Order Aberrations. Your glasses or contact lenses correct these problems and early LASIK (now called Traditional LASIK as opposed to Custom LASIK) also corrects them. However, Custom LASIK corrects more besides just these three problems. It also corrects Higher Order Aberrations.

There are about 60 higher order aberrations with more still being found. They mostly relate to night vision and are aspects of your quality of vision such as halos around lights, starburst shapes around lights, and ghosting (dim second images). They are detected in your vision by Wavefront technology when you have your eyes diagnosed for Custom LASIK.

What causes higher order aberrations is microscopic defects in the corneal surface. Until now, they have not been correctable and we have just lived with them. Most of them have no names but are expressed mathematically. Now, Custom LASIK can correct them, which is one reason why your LASIK results can be so spectacular.

If you are tired of the hassle and continuing expense of glasses or contact lenses, and live in the Chicago, Arlington Heights or Schaumburg areas of Illinois, please visit the website of Doctors for Visual Freedom to schedule a free initial consultation, at www.doctorsforvisualfreedom.com.

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