PRK – Photo Refractive Keratectomy
Photo refractive keratectomy or PRK surgery is a laser treatment applied to the cornea to correct a person’s vision. It is used to treat myopia, hyperopia, and astigmatism. The treatment works by the laser changing the shape of the eye. The outer epithelium is removed and the laser then removes the proper amount tissue in a manner that corrects a person’s refractive error. A contact lens is placed on the eye after the procedure and left in place for several days. Once the epithelium has grown back over the cornea, the contact lens is removed. The vision may not be clear for up to 2 weeks as the eye heals. The first PRK was performed by Dr. Theo Seiler in Berlin, Germany in 1987.
Lasik – Laser-Assisted in-Situ Keratomileusis
Lasik surgery is done by first making a thin flap of the outer 100 to 180 microns thick using either a keratome with a blade or with a femtosecond laser. A hinge of tissue is left on the flap and the flap is lifted over out of the way. The laser is performed to change the shape of the cornea and the flap is put back in place. The person usually has very good vision the next day.
Lasek – Laser-Assisted Sub-Epithelial Keratectomy or Laser Epithelial Keratomileusis
In Lasek, an alcohol solution is place on the cornea for a few seconds. This loosens the cornea epithelium and it is either removed or lifted and place to the side. The laser is performed and the epithelium placed back in position. If the epithelium is retained, it can lead to faster healing and return of clear vision. Lasek and PRK are very similar procedures.
Since the epithelium is removed, the eye can be very painful for the first few days. Insertion of the contacts lens can reduce the pain considerably. The epithelium will heal back and cover over the cornea in 4-7 days. The vision will be somewhat blurred until the epithelium has healed completely. It may take 2 weeks or so for the person’s vision to be fully restored.
Complications of Laser Refractive Surgery
- Ocular pain
- Dry eyes
- Blurred vision
- Under or over correction
- Reduced best corrected vision
- Scarring and/or corneal haze
- Increased visual aberrations
- Photophobia or light sensitivity
- Flap complications with Lasik
PRK vs Lasik
Both procedures provide excellent results with approximately 95 % of patients seeing and happy with their vision. PRK takes longer for the vision to clear, is more painful, and you don’t get the wow factor of seeing clearly almost immediately. There are no flap complications with PRK. Lasik may cause more dry eye problems but gives faster results. In patients with thinner corneas who are not candidates for Lasik, PRK may be possible as there is no corneal flap made which cuts through 100 or more microns of corneal tissue.
Both procedures provide excellent results. Each eye surgeon has their own preferences about the type of surgery they prefer. Depending on the status of your eye you may be a better candidate for one or the other, such as dry syndrome and/ or thin corneas.