Effect of variations in surgical technique and patient management on outcomes of photorefractive keratectomy

PURPOSE: To describe variation in surgical and patient management and to assess their effect on 12-month outcomes of photorefractive keratectomy (PRK). METHODS: The following variations in surgical/patient management related to PRK were observed and assessed: treatment based on cycloplegic refraction, administration of anesthesia, marking of visual axis, diameter of zone marker, method of epithelial removal, use of intraoperative artificial tears, type of fixation during surgery, replacement of epithelium after surgery, use of a bandage contact lens or two pressure patches, and use of topical nonsteroidal antiinflammatory drugs after surgery. The outcomes assessed were spherical equivalent manifest refraction, spectacle-corrected visual acuity and uncorrected visual acuity. RESULTS: One year clinical outcomes were assessed prospectively for a group of 645 eyes that underwent PRK or photoastigmatic keratectomy. Spherical equivalent refraction and uncorrected visual acuity were better with decreasing amounts of preoperative myopia (both F>30.0, both p=0.0001). Although some surgical variations produced statistically significantly better uncorrected visual acuity on univariate analyses, none of the variations in the techniques assessed were found to be statistically significantly related to clinical outcomes after controlling for preoperative spherical equivalent refraction (all F<2.5, all p>0.10). None of the surgical variations were associated with loss of spectacle-corrected visual acuity (all p>0.10). CONCLUSION: Clinical outcomes of PRK were not significantly affected by minor variations in clinical and surgical practice.