Beyond LASIK: PRK //
PRK is a another path to laser vision correction. Photorefractive keratectomy (PRK) uses the excimer laser in the same way as LASIK, and patients’ vision correction results are similar. The main difference between PRK and LASIK is that in PRK only the very top (epithelial) layer of the cornea is removed (or moved aside) before the excimer laser sculpts the cornea.
Many PRK surgeons use a blunt, gently vibrating microkeratome to remove the epithelial layer. LASEK and Epi-LASIK, described below, are other PRK techniques. New approaches, such as advanced surface ablation in which the cornea is cooled either before or after surgery, help reduce the discomfort that may occur after PRK. The patient may also be given topical antibiotics and anti-inflammatory medications and oral pain medications to reduce discomfort and speed healing after surgery. A “bandage” soft contact lens is used to promote epithelial healing, which takes about four days.
While LASIK patients often report clear, improved vision by the day after surgery, it may be a few days before vision stabilizes for PRK patients. The cornea’s epithelial layer re-grows during this time. The thicker corneal flap created in LASIK is not made in PRK, so if there is a concern about potential flap complications, the surgeon may recommend PRK. If the patient’s corneas are too thin to meet LASIK standards, if he or she had LASIK previously, or if other eye health factors are involved, the surgeon and patient may decide that PRK would be a better choice.
Wavefront-guided PRK offers additional vision correction, similar to wavefront-guided LASIK. Though thousands of wavefront-guided PRK procedures have been safely and effectively performed in the United States, the FDA approval process has not yet taken place, so wavefront-guided PRK is considered an “off-label” use of the technology. Professional medical standards permit Eye MDs to use this and other “off-label” procedures and medications.