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For more information, see our Frequently Asked Questions.
LASIK
Performed since the early 1970's, refractive surgery procedures improve vision due to nearsightedness (myopia), farsightedness (hyperopia) and astigmatism. With the advent of the laser for refractive surgery (photorefractive keratectomy or PRK), a new era in eye care is unfolding. It has been found that the excimer laser procedure combined with the creation of a corneal flap (Lamellar Keratoplasty or LK) is an excellent technique for reshaping the surface of the cornea to correct nearsightedness and astigmatism. The combination of both procedures is called Laser Assisted In-Situ Keratomileusis (LASIK) and offers the accuracy of refractive lasers with the benefits of the LK procedure's speedy recovery.
The LASIK Procedure
A special instrument (microkeratome) is applied to the cornea, creating a thin flap of corneal tissue. The flap remains attached to the eye at one end. Next, the laser is used to reshape the cornea. The flap is then put back into position and the procedure is complete.
What is a Refractive Error
In normal vision, light enters the eye through the cornea and is focused at a single point on the retina at the back of the eye.
With a refractive error, there is a defect in the way light passes through the eye. Light rays do not refract (bend) properly to achieve a single focus point. Instead, light rays focus in front of the retina (nearsighted), behind the retina (farsighted), or at two different points (astigmatism).
Refractive errors usually result from a defect in the length of the eye or shape of the cornea.
Myopia or Nearsightedness
Close objects are seen clearly but distant objects appear blurred. Myopia is caused by a steeply curved cornea or elongated eye.
Hyperopia or Farsightedness
Close objects are blurred and distant objects are clear. Hyperopia is caused by a short eye.
Astigmatism
Objects at all distances appear indistinct and distorted. Astigmatism is caused by an unevenly curved or warped cornea.
What is Laser Light?
Normal light from the sun or a light bulb is made up of a range of energy that scatters and radiates in all directions. A rainbow shows the spectrum of visible colors, from red to violet, that make up normal or white light. Laser light is not radiation, as are x-rays, cosmic rays and gamma rays. It is made of a single color or wavelength of light, with all of the light rays traveling in the same direction (coherent light). The light itself is safe and does not become effective in medical treatment until it becomes highly concentrated through the use of special mirrors and lenses.
The Excimer Laser
A laser contains a device to create light in a similar manner as a light bulb, but more sophisticated and precise. With an excimer laser, when an electric current is passed through a tube containing a special gas (argon fluoride), a reaction occurs that produces ultraviolet light energy. The direction, focal point, intensity and release of the light from the tube are precisely controlled by the surgeon and the computer. As laser light is produced, it passes through a system of mirrors that result in all light rays traveling in one direction (coherent light). When light first exits the laser it is relatively weak, but then the light passes through a system of lenses which focus the energy to a fine point. As it gets closer to the focal point, the energy becomes more concentrated and the beam gains strength. Laser light reaches its maximum strength at the focal point, the point where all rays converge. The strength of the beam rapidly diminishes after passing the focal point, and can no longer affect other tissues in the eye.
Reshaping Vision
Instead of using heat to alter tissues like other lasers, an excimer laser beam breaks the bonds that link tissues together with only minimal effect on surrounding tissue. These unique properties allow the excimer laser to be used in the LASIK procedure to reshape tissue immediately beneath the surface of the corneal flap. After LASIK, light rays focus more precisely on the retina.
A computer, programmed by the doctor for each person's own correction factors, controls the laser and the reshaping of the cornea. The procedure is performed while the patient lies on her/his back. In treating myopia, the laser segment of the procedure starts with a narrow diameter beam. As the laser beam expands or moves, a tiny lens-shaped disc is created. The focal point of the beam only penetrates the cornea about two-thousandths of an inch (about half the thickness of a human hair). Only a small area in the center of the cornea is treated, essentially producing a concave lens over the visual axis. Finally, the corneal flap is replaced (without stiches) and the LASIK procedure is complete.
Is Monovision right for me?
As part of the natural aging process, our eyes gradually lose the ability to focus on near objects. As our ability to focus on near objects diminishes, reading small print or reading in dim light becomes increasingly difficult. This natural loss of reading vision usually begins around the age of forty and progresses into our sixties. This natural, normal aging process of the eye is known as Presbyopia.
Presbyopia may be dealt with in a number of different ways. Reading glasses or bifocals accommodate for this loss of reading vision. Another method of correction, which works well for many individuals, is known as monovision. Most people use contact lenses to achieve monovision, however monovision is also possible with the LASIK procedure. With a monovision correction, one eye is corrected for distance vision and the other eye is left slightly undercorrected to preserve one's reading or close vision. Since it is your brain rather than your eyes that interprets what you see, your brain is able to selectively focus on the clear image while the blurry image is suppressed. Because both eyes are in constant use, monovision will not cause any harm to your eyes.
Your specific visual needs are important to us. The doctor will discuss the correction options available to you at your pre-operative evaluation. If you are interested in monovision, you may be fitted with monovision contact lenses prior to your surgery to help you and the doctor decide if monovision is right for you. If it is decided that monovision is not the appropriate correction for you, both of your eyes will be corrected for distance vision. You will then need to wear reading glasses or bifocals for near vision.
In a small percentage of people, a monovision correction may not be accepted. If this is the case, the eye which was left slightly undercorrected for reading vision may be enhanced to full distance correction.
Laser Vision Hotline
(414) 272-2020
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