Laser Vision Correction (PRK Lasik)

Timothy Chou, MD

Appointments: 631.444.4090
Fax: 631.444.4089

Laser vision correction is the use of an Excimer Laser to gently reshape the cornea to correct nearsighted, farsighted, or astigmatic vision. This procedure allows many patients to see without glasses for many activities such as driving or sporting activities, or to enter professions that have vision requirements such as the police or fire department. The Excimer Laser uses a cold beam of ultraviolet light to remove a thin layer of tissue from the surface of the cornea. Changing the shape of the cornea moves the focal point of the eye directly onto the retina allowing the individual to see clearly for distance vision. The laser is computer guided and so precise it can remove less than half the width of a human hair with each pulse.

Refractive Errors

Myopia (nearsighted) Hyperopia (farsighted) Astigmatism

Prior to undergoing Excimer laser vision correction, an accurate refraction is performed. Also, a computer generated topographical map of the cornea is measured. This three dimensional map of the corneal surface shows where the cornea is steepest and helps to insure the accuracy of the data programmed into the laser's computer.


Excimer laser vision correction procedures currently available include PRK (photo refractive keratectomy) and LASIK (laser assisted keratomileusis). With PRK, there are no incisions made into the cornea. The laser is used to gently remove the corneal epithelium (the surface cells of the cornea). This layer naturally regenerates itself in a few days. The laser is then applied to the underlying layers of the cornea to permanently reshape the curvature and change the focal point of the eye.

With LASIK a diamond blade called a microkeratome is used to painlessly lift a thin corneal flap. The cornea is then reshaped beneath the flap and the flap is closed. Generally, no sutures are needed to hold the flap in place.

Both procedures are virtually painless. An eye speculum holds the eye open and restricts eyelid movement. Either procedure takes about five minutes per eye and the actual time for the laser treatment is often less then one minute. People having PRK may experience eye irritation or pain for a few days while the epithelium heals. People having LASIK experience eye irritation that often resolves within 24 hours. The degree of discomfort depends on the procedure and on individual healing. Both procedures produce excellent visual results in the vast majority of patients although LASIK patients experience a more rapid return of good vision. Many patients return to work within 1 or 2 days. PRK patients may take a week to return to work and normal activities.

Excimer laser vision correction is not a new or experimental procedure. It has been performed in many countries since 1987 and in Canada since 1990. It was approved for use in the United States by the FDA in October of 1995. Over the past 10 years more than one million Excimer laser procedures have been performed worldwide The results speak for themselves. Better than 95% of patients achieved uncorrected vision of 20/40 or better and 80% achieved 20/20 vision by one year after treatment. A vision of 20/40 uncorrected is the legal standard to drive without glasses and also is the required vision to enter many professions. As with any surgical procedure there are always risks and possible complications. Not all patients are candidates for these procedures.

If you desire more information regarding excimer laser vision correction or a free consultation to see if you are eligible please call our Lasik coordinator at 444-4090. You can schedule a free evaluation or arrange to attend one of our monthly seminars on this exciting new procedure.