What Can Laser Vision Correction Do For You?

To understand why and how laser visionfocused not onto the retina but behind the retina.
correction works, it's best if you first understandIf the cornea and the crystalline lens had more
how your eyes work, and what types of visioncombined focusing power, or if the eye were
problems affect us.longer, then the light rays would be focused
How Your Eye Worksprecisely onto the
Just like a camera, the eye works by focusingAstigmatism. People whose eyes focus light rays
light rays. Light entering the eye first passesunevenly have astigmatism. Astigmatism occurs
through a transparent layer called the cornea. Thewhen the cornea has an irregular shape. The
cornea acts as a lens by focusing the light.cornea should be round and symmetrical like a
Located behind the cornea is another lens, knownbasketball, but in cases of astigmatism it is shaped
as the crystalline lens, that further focuses themore like a football. People with astigmatism see
light to make a clear image on the retina at theboth near and far objects out of focus.
back of the eye. Finally, the image is transmittedAstigmatism frequently accompanies
to the brain by the optic nerve.nearsightedness or farsightedness.
Just as a camera cannot produce a clearPresbyopia. Presbyopia (which comes from the
photograph if the incoming light is not focusedGreek for "old vision") refers to the gradual loss,
precisely onto the film, so the eye cannotas we age, of the eye's ability to adjust the focus
produce clear vision if the cornea and crystallinefrom far to near. Presbyopia is a normal part of
lens do not focus the light precisely onto thethe aging process, affecting each and every
retina.person, and usually begins to cause a problem
The most common vision problem is the inabilitywith near vision between the ages of forty and
to focus incoming light precisely onto the retina.fifty. It is corrected by the use of reading glasses
The result is blurred vision.or bifocals.
There are four types of focusing errors:Presbyopia occurs because the crystalline lens no
- Nearsightednesslonger adequately adjusts its shape to focus
- Farsightednessclearly on close-up objects.
- AstigmatismThough presbyopia is referred to as
- Presbyopia"farsightedness" by many people, it should not be
Nearsightedness. Nearsighted people see nearconfused with true farsightedness (hyperopia).
objects better than those farther away. InPresbyopia is caused by difficulty in changing the
nearsightedness (also known as myopia), light raysfocus from far to up close - a problem with the
from distant objects are focused not onto thecrystalline lens. True farsightedness is caused by
retina but in front of the retina. Nearsightednesstoo little focusing power in the eye a combination
occurs because the cornea and the crystalline lensof the cornea and the crystalline lens.
together have too much focusing power for theBoth presbyopia and hyperopia cause blurring of
length of the eye. If the cornea and the crystallinethe close-up vision, though hyperopia can blur the
lens had less combined focusing power, or if thedistance vision as well. Whereas presbyopia is an
eye were shorter, then the light rays would beaging effect and begins to be experienced
focused precisely onto the retina.sometime after thirty-five years of age,
Farsightedness. Farsighted people see farawayhyperopia affects people of all ages, even young
objects better than those that are near.children.
Farsightedness (also known as hyperopia) resultsPresbyopia can be present by itself or in
when the cornea and the crystalline lens togethercombination with nearsightedness, farsightedness,
have too little focusing power for the length ofor astigmatism.
the eye. Light rays from distant objects are