PRK was the original Excimer laser procedure for reshaping the cornea, first performed in the mid 1980's. Unlike LASIK, in PRK, the Excimer laser is applied to the surface of the cornea after the epithelium (the superficial layer) is removed. Because of the epithelial defect created in PRK, the discomfort is greater and the visual recovery prolonged compared to LASIK. The range of refractive errors which can be corrected by PRK is also not as wide as that of LASIK. However, for low to moderate refractive errors, the long-term results are equally good. Some patients who are not good candidates for LASIK may have PRK safely. Given the choice, however, the majority of patients elect to have LASIK over PRK.  If you are currently or planning to join one of the military services, PRK may be your only option for laser vision correction.  The outcome of PRK may be enhanced using a wavefront-guided laser procedure (Custom PRK).

The Treatment

2. Excimer laser is applied to reshape (ablate) the cornea.

3. The corneal epithelium re-grows over the treated area.

4. The "flatter" cornea now bends light to become focused on the retina.

 

PRK for Myopia Animation

The procedure is done using eye drop anesthesia. First, the corneal epithelium, a thin layer of cells on the surface of the cornea, is removed. Then, the computer controlled precision of the Excimer laser is applied to remove a predetermined amount of corneal tissue. Because an epithelial abrasion the size of the treatment zone is created, a bandage contact lens is placed on the cornea immediately after treatment. The amount of tissue to be removed is determined by the amount of nearsightedness, farsightedness, or astigmatism to be corrected. For most patients, only five to ten percent of cornea is removed to obtain the desired result. As healing occurs, the epithelium re-grows and covers the area of laser treatment. The contact lens is removed in 48 to 72 hours.