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Purpose: To develop a system for the examination of the ablated surface after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) and to correlate the surface regularity to the functional outcome., Methods: A Nidek Eas-1000 Anterior Eye Segment Analysis System was used to examine the ablated surface or the interface regularity immediately after PRK and LASIK. Eighty eyes were evaluated and divided into three study groups; group 1; regularity (18 eyes), group 2; mild irregularity (32 eyes) group 3; severe irregularity (30 eyes)., Results: At 12 months postoperatively, group 1 (regularity) showed the best percentage of eyes with 0 haze (100%) and with a refraction +/- 1.00 D of plano (89%); group 2 (mild irregularity) 84% had 0 haze and 62% were +/- 1.00 D of plano; group 3 (severe irregularity) 27% had 0 haze and 47% were +/- 1.00 D of plano., Conclusion: The patients with no postoperative irregularity had a sharply lower incidence of haze and a better refractive outcome with respect to plano, confirming the influence of ablation regularity on the results and the importance of this analysis in clinical practice.

Purpose: To assess a new method for decreasing corneal ablated surface irregularities after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) by performing a final smoothing immediately after the treatment., Methods: One hundred forty-seven eyes with ablation irregularities after PRK or LASIK using the Nidek ED-5000 excimer laser and examined with the Nidek EAS 1000, were randomized into two groups: 74 eyes had final smoothing and 73 eyes were patched immediately. Preoperative mean refraction for the smoothing group was -7.55 +/- 2.50 D and for the patched group, it was -7.30 +/- 1.90 D, (p = 0.04)., Results: AT 12 months after treatment, mean haze was 0.5 +/- 0.3 in the smoothing group and 1.2 +/- 0.4 in the patched group (p = 0.006); mean spectacle-corrected visual acuity was 1.1 +/- 0.25 in the smoothing group and 0.95 +/- 0.18 in the patched group (p = 0.02); the percentages of eyes within 1.00 D of the planned correction was 68% in the smoothing group and 33% in the patched group., Conclusion: Performing a final smoothing immediately after PRK or LASIK improves refractive and optical outcomes.

Background: Four human corneas that had undergone photorefractive keratectomy (PRK) and subsequent penetrating keratoplasty were examined by means of light and electron microscopy in an attempt to detect possible causes for complications after PRK., Methods: Four eyes with a central corneal leukoma resulting from a previous PRK treatment underwent penetrating keratoplasty respectively 3 days, 3 months, 5 months, and 13 months after the refractive procedure. Different excimer laser instruments (Meditec MEL 50, Summit UV200, and VISX 20/20) had been used. The corneal buttons removed were submitted for light microscopy, electron microscopy and immunohistochemistry., Results: An immature (one to two layers, basement membrane anomalies) but continuous epithelium was present even in the 3-day specimen; between six and eight epithelial layers could be seen in the 13-month specimen, which still presented an undulated aspect of the otherwise normal basement membrane. A continuous acellular collagen layer underlying the epithelium of the ablated area was detected in the superficial stroma of all examined corneas. No Descemet's membrane or endothelial alterations could be seen., Conclusions: Despite recovery of a continuous epithelial layer as early as 3 days after PRK, abnormalities of both epithelium and superficial stroma could be detected in all specimens, including the one obtained 13 months after the refractive procedure.