PRK or photo refractive surgery is a laser treatment that corrects a person’s vision by the laser changing the shape of the eye. The laser removes tissue from the cornea (clear portion of the front of the eye) which corrects a person’s refractive error. PRK can be used to correct myopia (nearsightedness), Hyperopia (farsightedness), and astigmatism (abnormal shape of the eye). PRK surgery was the first laser surgical procedure used to correct vision. The first PRK was performed by Dr. Theo Seiler in Berlin, Germany in 1987.
PRK Eye Surgery
After installation of anesthetic or numbing eye drops, a speculum is used to hold the eyelids open. Either a spinning brush or blade is used to remove the outer layer of the cornea called the epithelium. The central 8 to mm are removed. The cornea surface is dried and the excimer laser run by a computer precisely removes tissue from the cornea to change its contour. The excimer laser is a cold laser and does not produce any heat. Once the laser is complete a contact lens is place on the eye. Depending on the age of the patient and the severity of the refractive error, the surgeon may use Mitomycin-C briefly applied to the cornea. This helps reduce any scarring that may occur.
LASEK or Laser-Assisted Sub-Epithelial Keratectomy
The LASEK procedure is very similar to PRK. An instrument to hold alcohol on the cornea is placed on the eye. The alcohol is drip onto the cornea and left for several seconds. The alcohol is rinsed away. The epithelium is now loose and can be moved to the side. The laser is then performed. If the epithelium is in good condition it can be placed back in place. If not then a contact lens is placed on the eye just in PRK.
Since the central epithelium is removed during the PRK surgery, it has to heal back before the vision becomes clear. It may take 5 to 7 days for the epithelium to heal and cover the cornea. It may still take a week or more for the cells to become healthy. A person can have significant pain for the first few days until the epithelium heals. Many doctors give their patients a diluted anesthetic eye drop to relieve the pain. You may also take oral pain medication. You will use an antibiotic and prednisone eye drop. Some eye surgeons may also use a non-steroidal anti-inflammatory eye drop for the first few days.
Complications of PRK
- Eye pain
- Blurred vision
- Corneal scarring
- Dry eyes
- Over or under correction of the vision
- Corneal haze
- Reduced best correctable vision
- Photophobia or light sensitivity
- Increased visual aberrations
PRK vs Lasik
Both of the procedures provide excellent vision. Nearly 96% of patients are happy with their vision. PRK takes longer before it provides good vision, has more pain, and you don’t get the nearly instant results as with Lasik. Lasik provides good vision by the next in most cases. It is less painful. Lasik may cause more dry eye problems after surgery. There are complications related to the flap that is formed during Lasik surgery. PRK may be preferred in patients with thin corneas.
PRK provides excellent vision results. The post-op healing time for good vision is approximately 10 to 14 days. Some people may have a faster vision recovery.