Surface Treatment or Photorefractive keratectomy (PRK)
Some potential laser vision correction candidates may not be well suited for LASIK, ( with the protective flap). For example, patients who are exposed to frequent facial trauma, such as a professional boxer should not under go LASIK , because the flap can be disturbed in the event of a serious eye injury. Patients with a history of radial keratotomy surgery, patients with a thinner than average cornea, patients with an unhealthy cornea surface, or patients with an atypical corneal shape may not be well suited for LASIK for medical reason. For those patients who are not good candidates for LASIK, surface treatment technique may be the better alternative.
Surface treatment or photorefractive keratectomy (PRK) is sometimes also called advanced surface ablation (ASA). Epi-LASIK is another type of surface treatment that utilizes a specialized instrument (see illustration below). We have found that Epi-LASIK has a slower recovery than PRK. In all these techniques the surface of the cornea (the epithelium) is first removed and then the excimer laser is applied to reshape or sculpt the cornea from the top downwards, rather than under a protective flap. The epithelium is like a veneer covering of the cornea. After the treatment, the recovery may be prolonged when compared to LASIK, because the healing of the surface (or regeneration of new epithelium) is a slow process that can take several days for the initial phase and several weeks for final phase.
Most patients can return to normal visual activities in about five to seven days after the procedure. Because everyone heals differently, it can take several weeks to months to achieve the final visual outcome. The main difference between surface treatment and LASIK is that surface treatment has a slower visual recovery and involves more discomfort in the immediate post-op interval than LASIK. After surface treatment, patients are provided additional medications and instructions to reduce discomfort and facilitate recovery.
LASIK patients are more rapidly satisfied with their results than patients who undergo PRK. However, the final visual results of either procedure are identical. Surface treatment has been demonstrated to provide a safe and effective alternative to LASIK, for those patients who are not suitable candidates for LASIK.
Epithelial sheet is created using a plastic separator
Sheet is lifted back and laser treatment is applied