Gimbel H V, DeBroff B M, Beldavs R A, van Westenbrugge J A, Ferensowicz M
Gimbel Eye Center, Calgary, Alberta, Canada.
J Refract Surg. 1995 Jan-Feb;11(1):36-41. doi: 10.3928/1081-597X-19950101-10.
Photorefractive keratectomy relies on precise ablation of cornea stromal tissue to achieve a desired change in refraction. The routine technique for photorefractive keratectomy has been manual debridement of the epithelium prior to performing excimer laser ablation. We investigated whether laser ablation versus manual debridement of the corneal epithelium influences the refractive result.
A retrospective matched controlled study analyzing the refractive outcome of 46 eyes after excimer laser photorefractive keratectomy was performed. Half of the eyes had the corneal epithelium ablated with the excimer laser, while the other half had mechanical removal. Topical postoperative corticosteroid dosing was different in the two groups. All photorefractive keratectomies were performed by the same surgeon (H.V.G.). The two groups were analyzed for statistical differences in refractive outcomes and corneal haze after 6 months.
The mean preoperative spherical equivalent refraction in the laser removal group was -5.11 diopters (D), and -5.09 D in the manual group. At 6 months postoperatively, the mean spherical equivalent refraction in the laser group was +0.03 D and -0.40 D for the manual group (p = .21). At no point postoperatively was there any significant difference in the mean refractive outcome or variance of the refractive results between the two groups, although there was a trend toward greater correction with laser ablation of epithelium. There was no statistical difference in the amount of stromal haze by slit-lamp microscopy in the two different debridement groups. There was no significant difference in final uncorrected visual acuity, rate of reepithelialization, or reported incidence of halos or glare between the two groups.
There was a tendency toward greater refractive correction at 6 months using the laser for corneal epithelial removal than manual debridement, although the difference was not statistically significant. The trend toward slightly higher correction emphasizes the need for care when removing epithelium with the laser to prevent concomitant stromal ablation.
准分子激光角膜切削术依靠精确消融角膜基质组织来实现预期的屈光改变。准分子激光角膜切削术的常规技术是在进行准分子激光消融之前手动去除上皮。我们研究了激光消融与手动去除角膜上皮是否会影响屈光结果。
进行了一项回顾性配对对照研究，分析46只眼准分子激光角膜切削术后的屈光结果。其中一半眼睛的角膜上皮用准分子激光消融，另一半则采用机械去除。两组术后局部使用皮质类固醇的剂量不同。所有准分子激光角膜切削术均由同一位外科医生（H.V.G.）实施。分析两组术后6个月屈光结果和角膜混浊的统计学差异。
激光去除组术前平均等效球镜度为-5.11屈光度（D），手动组为-5.09 D。术后6个月，激光组平均等效球镜度为+0.03 D，手动组为-0.40 D（p = 0.21）。术后两组在平均屈光结果或屈光结果方差方面均无显著差异，尽管激光消融上皮有更大矫正的趋势。两种不同清创组通过裂隙灯显微镜观察到的基质混浊量无统计学差异。两组在最终裸眼视力、上皮再形成率或报告的光晕或眩光发生率方面无显著差异。
使用激光去除角膜上皮在术后6个月时比手动清创有更大屈光矫正的趋势，尽管差异无统计学意义。稍高矫正的趋势强调了使用激光去除上皮时需谨慎操作以防止伴随的基质消融。
