Laser Eye Surgery - Lasik - Other Types of Laser Eye Surgery

Photorefractive keratectomy or PRK is an alternative to LASIK eye surgery that is intended to correct a patient’s vision and reduce his or her dependence on glasses or contact lenses. This procedure, although older than LASIK, also permanently changes the shape of the cornea using a laser, but unlike LASIK, no corneal flaps are created.

PRK eye surgery utilizes a laser called an excimer laser and is used to correct nearsightedness and in some cases astigmatism. PRK was the first type of laser eye surgery approved by the FDA. This type of laser vision correction removes a precise amount of corneal tissue using a “cold” ultraviolet laser. This laser uses a sophisticated computer that calculates the amount of tissue to be removed and then removes the tissue from the center of the patient’s cornea, decreasing its curvature. This change in the cornea brings the focal point of the eye closer to the retina, improving the patient’s distance vision.

It is estimated that up to 80% of the myopic population physically qualifies for PRK laser eye surgery. There are several basic criteria that a patient must meet in order to qualify:

Normal ocular health
Patient must be at least 19 years of age
Stable refractive error that is correctable to 20/40 vision or better
Patient must not be pregnant
Patient must have realistic expectations of final results with a complete understanding of the benefits and risks of having PRK surgery
Pupil size 6 in room light

There are also a few pre-existing conditions that might disqualify a patient from being a suitable candidate for this type of surgery. These conditions include:

Collagen vascular disease (e.g. corneal ulceration or melting)
Ocular disease
Systemic disorders such as diabetes or rheumatoid arthritis
History of side effects from steroids

Since PRK does not involve the creation of a permanent flap in the corneal layers, the structural integrity of the cornea is less altered by this type of laser eye surgery. This procedure can allow patients whose corneas are abnormally thin to have vision corrective surgery in cases where LASIK is not possible. However, PRK can be a more painful procedure and the healing process can take longer, making visual recovery slower. Individual diagnosis will determine which surgery is best for each individual patient.

Laser epithelial keratomileusis or LASEK is another type of laser eye surgery that is technically a variation of PRK. This type of surgery is used for patients whose corneas are too thin or too flat to be good candidates for LASIK surgery. This type of laser eye surgery was developed to reduce the chances of complications that arise when the corneal flaps that are created during LASIK surgery are not of ideal thickness or diameter.

In LASEK procedures the cornea is cut with a finer tool than the cutting tool used in LASIK surgery that is called a trephine. The surgeon then covers the patient’s eye with an alcohol solution that loosens the edges of the epithelium. After the loosening of the epithelium, the surgeon uses a tiny hoe to lift the edge of the epithelial flap and then gently fold it back out of the way. Then an excimer is used to sculpt the corneal tissue underneath. Afterward the epithelial flap is placed back on the eye with a kind of spatula.

In many ways what one can expect from LASEK is similar to what can be expected from LASIK, with a few differences. The flap edge should heal in about one day according to doctors, but patients usually wear a bandage contact lens for about four days after the procedure. Recovery to good vision takes a bit longer with LASEK procedures – from four to seven days. Healing time and side effects vary from patient to patient as with any procedure.