PRK (Photorefractive Keratotomy)
Photorefractive Keratotomy or PRK is a type of laser vision correction procedure that has been available in the U.S. for more than 20 years. PRK is considered the predecessor to the more commonly known LASIK procedure and uses the same excimer laser technology.
PRK at a Glance
What Is PRK?
PRK uses an excimer laser to correct vision by removing microscopic amounts of tissue from the surface of the cornea to improve its refractive – or light focusing – capabilities.
PRK uses topical (eye drop) anesthesia to numb the eye and a speculum is placed over the eye to keep the eye lids open. Then the outer layer of the cornea, known as the epithelium, is removed either mechanically (with a small sweeping tool or brush) or with a laser. After the epithelium is removed, the excimer laser is deployed over the surface of the cornea to remove a micro-thin layer of cornea tissue, leaving behind a smooth shaped surface to improve refraction – the focus of light rays into the eye.
Finally, a contact lens is placed on the eye to act as a bandage – protecting the cornea until the epithelial layer of cells reforms, typically within 5 days. While the procedure itself is relatively painless, once the anesthesia wears off patients typically experience discomfort, blurred vision, dry eye, glare and haloes during the recovery process. This is treated with a variety of eye drops used to prevent inflammation, infection and help maintain the eye’s moisture balance. This healing process can take several days and up to three months for patients to achieve their best corrected vision.
Are You a Candidate for PRK?
A thorough evaluation by a board-certified ophthalmologist is the best way to determine candidacy for laser eye surgery such as PRK. This, in part, is to ensure that there is enough suitable corneal tissue to support the reshaping required to achieve the desired amount of correction, and that the tissue is healthy, free of disease, and likely to heal well. A qualified ophthalmologist will measure the thickness of the cornea and, among other diagnostic tests, review the patient’s medical history and check the overall health of the eyes and, specifically, the corneas.
PRK is particularly well suited for patients seeking a laser vision correction option, but for whom LASIK may not be appropriate. This can include patients with thin corneas, large pupils, corneal scarring or those who participate in high contact sports, such as basketball or football, or who have jobs with a high risk for eye injury including fire fighters.
Is PRK Safe?
As a laser vision correction procedure with more than 20 years of clinical performance, PRK is an excellent alternative to the more popular LASIK procedure. Like LASIK, PRK is both safe and effective. Visual outcomes with PRK are similar to LASIK, however the recovery process can be challenging to some as there is some discomfort involved. In addition, the PRK recovery process can impact the final best corrected visual outcome, resulting in either under correction or overcorrection that may be resolved with additional treatment.
For those who struggle with the issues related to reliance on corrective glasses and contact lenses for clear vision, and for whom LASIK is not an appropriate choice, PRK is an excellent choice. Unlike LASIK, the PRK procedure does not include creating a flap in the corneal tissue prior to performing the laser vision correction. By preserving more of the corneal tissue for treatment, PRK allows more people to take advantage of the benefits of laser vision correction.