Late natural history of corneal topography after excimer laser photorefractive keratectomy

To investigate the 3 month to 1 year natural history of corneal topography after excimer laser photorefractive keratectomy (PRK). A prospective, multicenter, nonrandomized comparative study. A total of 75 eyes of 68 patients with myopia were studied. Excimer laser photorefractive keratectomy and computer-assisted videokeratography were performed. Preoperative and 3, 6, and 12 month postoperative topography patterns were compared and changes assessed by averaging defined sectors of the ablation zone in individual maps to produce composite “average” topography maps. Corneal topography was relatively smooth 3 months after PRK. By 12 months, the corneal contour in general had become even more uniform. No “central island” effect was observed. When looking at right and left eyes independently, there was a tendency toward maximum flattening nasally. Corneal topography in general continues to smooth from 3 to 12 months after PRK, possibly as a result of epithelial and stromal healing and remodeling. Right and left eyes on average show mirror-image, spatially oriented topography patterns.