LASIK for Vision Correction
What Is LASIK?
Laser in-situ keratomileusis or LASIK is a procedure used to alter the curvature of the cornea (the clear covering of the from of the eye that bends or refracts light as it enters the eye).
For clear vision, the cornea must have the right shape to focus incoming light precisely on the retina, the light sensitive part of the back of the eye. If the cornea is too steep, too flat or irregular in shape, it cannot bend the light properly to focus it on the retina. This is called a refractive error. Then, eyeglasses or contact lenses may be needed to bend the incoming light necessary for clear vision.
How Does LASIK Work?
In LASIK, an instrument called a microkeratome is used to separate the layers of the cornea, crating a small, thin flap of tissue on the front of the cornea. The flap is folded back and excimer laser is used to reshape the corneal tissue underneath. An excimer laser uses a cool ultraviolet beam to very precisely remove just the right amount of corneal tissue. This reshapes the cornea to enable it to bend the light at the angle needed to focus it on the retina.
For people who are nearsighted, LASIK flattens the too-steep cornea. For those who are farsighted, it creates a steeper cornea. To correct astigmatism, the laser is used to smooth an irregular or oval shaped cornea.
After the laser is used, the flap is replaced, covering the area where the corneal tissue was reshaped.
LASIK is performed on an outpatient basis, with the actual procedure taking 15-20 minutes. Of this time, the laser is usually used for less than a minute. After the procedure, the eye heals on its own and does not require stitches.
Post-operative care for LASIK usually takes up to three months. It typically requires a return visit 24 hours after the procedure, then again one week, one month, and three months later.
How Effective Is LASIK?
LASIK can be an effective procedure to reduce or eliminate dependence on eye glasses or contact lenses for distance vision. The large majority of LASIK patients obtain 20/40 or better vision (the vision that many states require to drive without corrective lenses). Six to ten percent of patients may require an additional procedure, often called an enhancement.
LASIK is most effective as a treatment for nearsightedness, but is also effective for patients who are farsighted or who have astigmatism. LASIK does not eliminate presbyopia, a natural part of the aging process that generally becomes noticeable after age 40. It is characterized by difficulty focusing on near objects and reading glasses may be needed.
The results of your LASIK procedure will depend, in large part, on finding an experienced doctor. Beware of those who promise or guarantee a perfect result or who offer bargain prices with little or no discussion of follow up care or potential side effects.
Are There Side Effects to LASIK?
Yes, LASIK is surgery and in rare instances, patients experience side effects or complications. The most common side effects include night glare, dry eyes, and loss of the sharpness of vision.
Night glare is most often associated with patients with high nearsightedness and large pupils. Your doctor of optometry may measure your pupil size and help determine if you are at high risk for this complication. Most patients have a small amount of night glare for the first few days/weeks following LASIK.
Often, patients notice dry eyes during the first few weeks following LASIK. A few patients have persistently dry eyes that require treatment following the procedure. In some cases, it may be necessary to treat this dryness even before the procedure for best results. Your doctor of optometry can determine what treatment, if any, would be required and provide that to you.
Although rare, a few patients experience a loss of the sharpness of vision. Irregularly shaped corneas occasionally result from uneven exposure to the laser or irregular healing patterns of the patient. This results in decreased quality of visual acuity.
Who Is A Good Candidate For LASIK?
The American Optometric Association recommends that candidates for LASIK be 18 or older, in good general health, with stable vision and no abnormalities of the cornea or the external eye. If you are interested in LASIK, your doctor of optometry can help decide if it is the best treatment for you.