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[摘要]
目的：观察准分子激光角膜瓣背面基质切削(undersurface ablation of the flap， UAF)治疗LASIK术后屈光回退的安全性和有效性。
方法：对12例22眼LASIK术后有屈光回退的患者进行角膜瓣背面基质切削，术前球镜度数平均为-2.27±0.88D，散光度数为-0.44±0.30D，中央角膜厚度平均为424.9±8.2μm，术后观察1a，随访检查包括术后视力、屈光不正度数、角膜后表面高度、波前像差仪等。采用t检验或χ2检验进行统计学处理。
结果：术中测量角膜基质床厚度平均275.4±9.3μm； 角膜瓣厚度平均144.7±7.5μm，切削深度平均28.1±9.3μm。术后1a裸眼视力(uncorrected visual acuity， UCVA)4.99±0.04，最佳矫正视力(best corrected visual acuity， BCVA)5.03±0.04，BCVA相比术前无1例下降者。屈光不正球镜度数至术后1a时-0.22±0.19D，相比术前差异有统计学意义(t=10.232， P<0.001)； 散光度数1a时-0.24±0.26D，与术前相比有统计学意义(t=2.365，P=0.028)。角膜后表面高度值术前1.95±1.68μm，术后1a 2.00±1.88μm，两者差异无统计学意义(t=0.090， P=0.929)。彗差由术前0.283±0.112μm变化到术后1a时0.331±0.149μm，两者差异无统计学意义(t=1.452， P=0.161)； 球差由术前0.320±0.119μm变化到术后1a时0.341±0.103μm，两者差异无统计学意义(t=0.390， P=0.674)。
结论：以合理的手术设计为基础，UAF治疗LASIK术后屈光回退是安全和有效的，可以作为一种治疗屈光回退的选择之一。
[Key word]
[Abstract]
AIM: To investigate the safety and efficacy of undersurface ablation of the flap(UAF)for laser
in situ keratomileusis(LASIK)retreatment in eyes with regression.
METHODS: Twelve patients(22 eyes)with regression after LASIK were performed undersurface ablation of the flap. The mean of preoperative refractive error was -2.27±0.88D, the astigmatism was -0.44±0.30D, the central corneal thickness was 424.9±8.2μm. The follow-up time was 1a, including visual acuity, refractive error, the elevation of posterior cornea, WavScan. The data was analyzed with Student's t test and χ2 test.
RESULTS:During the operation, the measured stromal thickness was 275.4±9.3μm, the flap thickness 144.7±7.5μm, the depth of ablation 28.1±9.3μm. The mean postoperative uncorrected visual acuity(UCVA)was 4.99±0.04, best corrected visual acuity(BCVA)5.03±0.04, at 1a follow up. There was no patient with postoperative BCVA decreasing, compared to preoperation. Mean spherical refraction decreased to -0.22±0.19 D at 1a follow up(t=10.232, P<0.001)and the astigmatism decreased to -0.24±0.26 D(t=2.365, P=0.028). The elevation of posterior cornea changed from 1.95±1.68μm preoperatively to 2.00±1.88μm after 1a, but there was no statistical significance(t=0.090, P=0.929). The coma changed from 0.283±0.112μm preoperatively to 0.331±0.149μm after 1a(no statistical significance, t=1.452, P=0.161)and the spherical aberration changed from 0.320±0.119μm to 0.341±0.103μm(no statistical significance, t=0.390, P=0.674).
CONCLUSION:UAF, as one of a choice, is an effective and safe procedure for the treatment of regression after LASIK, based on the reasonable surgery design.
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