Photorefractive Keratectomy (PRK)
In this procedure, the laser treatment is directly applied to the surface of the cornea, resulting in the removal of the surface epithelium. After the surgery, the corneal epithelium requires two to five days to regenerate, during this period, the eye is very uncomfortable, and the vision is blurry.
Functional vision typically returns after five days, whereas normal vision may require two or more weeks to return. The patient’s vision may fluctuate to some degree for a period of several weeks, but stabilize after four-to-six months.
PRK is most useful for patients with less than 4.00 diopters of myopia, because of the depth of the corneal tissue removed is relatively shallow. There is no significant loss of structural integrity of the eye after PRK. However, some patients may temporarily develop corneal haze, which may slightly affect vision. The more myopic the eye, the deeper the treatment required and the greater likelihood there is haze. Usually, any corneal haze disappears within six months, but there have been patients in which the haze persists to some degree indefinitely.