Photorefractive keratectomy [PRK]
PRK is an out patient procedure in which, under eye drop anesthesia, the skin-like surface layer of the cornea (epithelium) is removed with an alcohol-based liquid, a rotative brush or an epi-keratome. The exposed corneal tissue is then reshaped by the laser in the same way as LASIK. After the procedure, you will wear a soft contact lens (bandage contact lens) until the regeneration of the epithelial layer is completed (4-5 days). Healing responses vary from one patient to another. This technique is most often used for people whose cornea may not be suited to create a corneal flap required for LASIK.
- The PRK surgery can correct nearsightedness (myopia), farsightedness (hyperopia) and astigmatism
- To correct myopia, the laser flattens the curvature of the cornea by removing cell layers located mainly at its centre
- To correct hyperopia, the laser creates a groove at the periphery of the cornea, therefore making the centre more curved
- The amount of corneal tissue removed is calculated based on the pre-operative determination of the power of your eye and on its shape