You know I’ve mostly focused on LASIK procedures over the last while, so here are some notes on other eye surgery procedures:

Photorefractive Keratectomy (PRK)

Laser vision correction with PRK is very similar to LASIK. The biggest difference is that no knife (microkeratome) is used and no corneal flap is created. Instead, the excimer laser makes its correction directly on the surface of your cornea, removing the central epithelium (the first corneal layer) and Bowman’s layer (the second corneal layer) in the process. This results in several days of potential discomfort and blurred vision until the epithelium regenerates.

The actual laser part of the procedure takes twenty to ninety seconds. At the end of the procedure, a clear-bandage contact lens is placed over your eye to help keep you comfortable while the corneal epithelium regenerates (usually three to five days).

A typical PRK procedure takes about three to five minutes per eye. Operating on just one eye, or both eyes on the same day, is a decision to be made by the patient after discussing the pros and cons with the surgeon. Because the return of functional vision is prolonged under PRK, most surgeons prefer to wait at least one week before operating on the second eye.

Patients with certain corneal problems, such as an irregular corneal surface or a thin cornea, may be better candidates for PRK than for LASIK. The ultimate visual results are similar with PRK, although the recovery is somewhat prolonged in comparison.

One advantage of PRK over LASIK is that there is no risk of flap complications since no corneal flap is created. However, other potential complications of PRK are similar to those of LASIK. They include undercorrection, overcorrection, induced astigmatism, dry eye, haze, night glare and halos, loss of best corrected vision, infection or severe inflammation, and regression. Other disadvantages of PRK include the need for anti-inflammatory eye-drops for three months and the risk of corneal haze or scarring.

Regression occurs when a person appears to be adequately treated on the first few postoperative visits, but over the next several weeks to months begins to return toward the original prescription. The amount of regression is usually small; however, occasionally it is visually significant and requires an enhancement procedure. The enhancement procedure is usually performed six to nine months after the original procedure. The time period before the return of optimal vision is significantly longer than with an enhancement after LASIK.