Lasik

The LASIK (Laser In Situ Keratomileusis) procedure was developed initially for patients with higher degrees of myopia that may not respond appropriately to PRK (Photo-Refractive Keratectomy). With LASIK, an additional step involves the creation of a very thin flap (usually 160 microns in depth), which is laid back and the excimer laser is applied to the bed of the cornea instead of the surface as in PRK.

The flap is created by a small, mechanical device called a microkeratome. Since the epithelium has not been disrupted, no contact lens is necessary, and the patient has a quicker recovery time and less post-operative pain. The vision is usually clear within days, and there is less fluctuation in the post-operative period compared to that of PRK.

Pre-Operative Work-Up

Prior to doing refractive surgery, a complete eye exam is performed to assess the general health of the eye. A careful refraction is done, both dilated and un-dilated, since the glasses prescription is what dictates the laser correction.
Keratometry readings are taken which reflect the steepness of the corneal curvature.
Corneal topography is a computerized topographical map, which can detect irregularities in the cornea that may preclude an unsatisfactory outcome.

Contact lens patients must discontinue the use of their lenses prior to surgery for at least two weeks. The above tests are repeated at that point and if they are stable, the surgery may be done. This is crucial since contact lenses can change the shape of the cornea and therefore, the refractive error. If the refraction plugged into the laser is inaccurate, the outcome will be too.

Results

The outcome of PRK or LASIK depends on the type and severity of your initial refractive error. The long-term outcome is basically the same in PRK versus LASIK, in low to moderate amounts of myopia. In higher degrees of myopia, the LASIK outcome is better than PRK. An under or over correction is certainly a possibility. Generally speaking, most patients can expect an 85% chance of 20/25 vision or better. Legal driving vision in Colorado, which is 20/40 vision or better, can be expected in about 95% of cases.

If you need reading glasses over your contact lenses, or are in bifocals now, you will need glasses for reading after PRK or LASIK.

Risks

As in any medical or surgical procedure, refractive surgery has its limitations and risks. The most common problem is an under or over correction, which is discussed above in Results. There is no treatment for an over correction but an under correction can be treated with an enhancement procedure if necessary at no additional cost to the patient. Since these procedures are not 100% accurate, the physicians at the Eye Surgery Center of Colorado and North Denver Laser err towards under correction rather than over correction since it can be enhanced if necessary.

In the FDA study on PRK, approximately 1% of patients had a slight loss of best-corrected vision. This means that even with glasses or contacts, about 1% of patients who were 20/20 before the surgery had 20/25 or 20/30 vision after the surgery. This was due to a slight residual haze in the cornea. This tended to improve with time, but the FDA follow-up period was only one year. Had it been longer, the incidence of this problem would have likely been less. In patients with higher degrees of myopia, the incidence of corneal haze is lower after LASIK compared to PRK.

While rare (less than 1%), other risks include infection, corneal flap problems, and corneal surface irregularities.

"Could I go blind from this surgery?" We all fear losing our vision. NO CASES OF BLINDNESS HAVE EVER BEEN REPORTED WITH EITHER THE PRK OR LASIK PROCEDURES.

What to expect on the day of treatment

Surgical patients should make arrangements to be driven to and from the surgical center. If needed, we can provide door-to-door transportation courtesy of our Eye Surgery Center van. Please click on Surgical Center for more information.

Anesthetic eye drops will be instilled in the eye to be treated and you will be taken to a comfortable surgical suite and asked to lie down on your back. Your surgeon will line you up under the laser, and you will be asked to stare at a red flashing light. If you are having LASIK done, a small, delicate instrument is placed on the anesthetized eye, and the flap is created. The laser application is usually completed in seconds. The entire process is pain free, quick, and no needles are used.

It is normal to be apprehensive, and the staff is very understanding and supportive in this respect.

Post-Operative Course

If you have had PRK performed, the outer later of the cornea (epithelium) has been removed, a clear soft contact lens is placed over the eye after the procedure to protect it until the epithelium regenerates, which takes an average of three days. During this time, the vision is blurry, and the eye is irritated and scratchy. Once the epithelium has healed, the vision is clearer, but some fluctuation may persist for weeks after the procedure.

If you have had LASIK performed, the epithelium has not been disrupted and therefore, no contact lens is necessary and the patient has a quicker recovery time, and less post-operative pain. The vision is usually clear within days, and there is less fluctuation in the post-operative period compared to that of PRK. However, you may have some fluctuation in your vision for several weeks after the surgery.