角膜屈光力超过47D的LASIK手术后2a观察

Observation on LASIK of corneal refractive power above 47D 2 years later

目的:初步评定角膜屈光力超过47D近视眼进行LASIK手术的安全性、有效性、预测性与稳定性。方法:研究组系用PENTACAM地形图检查角膜前表面屈光力超过47D共30例50眼(其中角膜前表面符合部分亚临床期圆锥角膜条件的12眼,但后表面高度正常)的LASIK手术患者;另设30例50眼术前屈光度,最佳矫正视力(BCVA)与研究组无显著差异,但角膜屈光力小于47D的近视眼作LASIK手术作为对照组。对比观察手术后1,3,6mo;1,2a的裸眼视力、最佳矫正视力、术后屈光度与角膜地形图;其中角膜地形图对比内容有:前表面中央半径2mm内的最大屈光力平均值,角膜平均屈光力,中央岛效应;后表面屈光力变化,术后最佳矫正视力丢失(BSCVA)情况,记录术后并发症情况。结果:研究组与对照组在手术后1,3,6mo;1,2a的裸眼视力、最佳矫正视力和术后屈光度无明显差异;角膜地形图与术前相比:中央半径2mm内的最大屈光力平均值和角膜平均屈光力均明显好转,且与近视度数减低值相符;两组术后出现中央岛效应的眼数相同;两组角膜后表面屈光力较术前无明显变化,且均无1例角膜膨隆症出现。结论:观察单纯角膜屈光力超过47D或仅角膜前表面部分符合亚临床期圆锥角膜标准,但后表面高度正常的近视眼作LASIK手术在2a内是有较好的安全性、有效性、预测性与稳定性。远期影响尚待观察。

AIM：To preliminarily evaluate the safety,effectiveness,predictability and stability of LASIK performed on myopia with corneal refractive power more than 47D.METHODS：Thirty cases（50 eyes） of LASIK surgery with corneal anterior surface refractive power more than 47D by Pentacam topography were selected as study group（corneal anterior surface of 12 eyes corresponded partly with the condition of sub-clinical phase of keratoconus,but the height of their posterior surface was normal）;Another 30 cases（50 eyes） of LASIK surgery with corneal anterior surface refractive power less than 47D who had no significant difference with study group in preoperative diopter and best corrected visual acuity（BCVA） as control group.Paired observation was conducted on uncorrected visual acuity（UCVA）,BCVA,postoperative diopter and corneal topography 1 month,3,6 months,1 year and 2 years after surgery;the comparative contents of corneal topography included：mean of maximum refractive power within 2mm of central radius of the anterior surface,mean corneal refractive power,central island effect;changes of refractive power of posterior surface,loss of postoperative best-spectacle corrected visual acuity（BSCVA）.The postoperative complications were recorded.RESULTS：There were no obvious differences in UCVA,BCVA or postoperative diopter between study group and control group 1 month,3,6 months,1 year,2 years after surgery;corneal topography compared with the preoperative：mean of maximum refractive power within 2mm of central radius and mean corneal refractive power were improved significantly,which was consistent with myopic reduction degree;the number of eyes with postoperative central island effect in two groups was the same;compared with preoperative,refractive power of corneal posterior surface in two groups had no apparent change,and no keratoconus occurred.CONCLUSION：LASIK for myopia only with corneal refractive power more than 47D or corneal anterior surface corresponds partly with the condition of sub-clinical phase of keratoconus,but the height of posterior surface is normal,of better security,effectiveness,predictability and stability within 2 years after surgery.Long-term influence remains to be observed.