Photorefractive Keratectomy (PRK)
PRK is a type of laser eye surgery that corrects refractive error by reshaping the surface of the cornea, rather than sculpting inside of the cornea. During PRK a corneal flap is not created. The recovery period for PRK is longer than for LASIK, and the procedure is rarely recommended, but for some it is the only realistic option. It is a safe and effective method for improving vision.
PRK is great option for patients who are not good candidates for LASIK because they have one or more of the following conditions:
- Thin corneas
- Corneal scars from trauma or infection
- Corneal dystrophy
- Recurrent corneal erosion
- Large pupils
PRK can treat nearsightedness (myopia), farsightedness (hyperopia), and astigmatism. Your ophthalmologist will use a corneal topographer to create a map of your cornea revealing irregularities and the steepness or flatness which needs to be corrected. The map created by the corneal topographer is used to guide the laser during surgery. If you wear contacts you will be asked to stop wearing them for a period of time before your eyes are mapped. You will need to refrain from wearing soft contacts for a few days and hard contacts for a few weeks. Refraction must be stable when your eyes are evaluated to determine how much correction is needed.
PRK is day surgery. It only takes a few minutes. You can choose to have surgery on both eyes during one procedure, but most people choose to have surgery on one eye first and return after a few days or a week to correct the second eye. Anesthetic eye drops are used to numb your eyes, and some patients may take a mild oral sedative. A speculum holds your eyelids open so that you do not blink, and a suction ring keeps your eye in position during the procedure. An excimer laser is used to remove tissue from the outside of your eye. You will be asked to stare directly at a target light during this part of the surgery.
As with LASIK, PRK can now be performed using wavefront mapping similar to Custom LASIK. This means that the procedure can treat higher order aberrations, which means that after a Custom PRK procedure, your vision may be even sharper and clearer than it was before with glasses or contact lenses.
After surgery, a bandage contact lens is placed on the eye and you will be given anti-inflammatory and antibiotic eye drops. Although you can leave a few minutes after the procedure, you will need someone to drive you home. The bandage contact is removed when the surface epithelium has healed, normally two or three days after surgery. You will have multiple follow-up visits, usually one day, three days, one week, one month, three months, and six months after the procedure. One drawback of PRK as compared to LASIK is the length of time before vision is fully improved. It can take six months to see the full results.
PRK has a longer recovery period, and carries a greater risk of scarring or corneal haze, as well as a somewhat increased chance of infection when compared with LASIK. Like other refractive surgery there is a risk of halos, glare, and loss of best corrected vision. Complications are rare.
PRK has been around since the early 1980’s but was not approved by the FDA until 1995. Superior refractive surgery methods have since been developed, but for some patients, PRK is still the best option. It is the oldest laser refractive surgery, and has proven to be a safe and effective way to improve vision.
