准分子激光屈光性角膜手术后人工晶状体屈光度数的预测

目的　探讨准分子激光屈光性角膜手术后 ,不同公式预测人工晶状体屈光度数的准确性及其校正方法。方法　应用第二代经验公式、第三代理论公式和BinkhoistⅡ公式 ,分别于准分子激光原位角膜磨镶术 (laserinsitukeratomileusis,LASIK)前、后测算 6 0例 (12 0只眼 )近视患者矫正至正视眼所需的人工晶状体屈光度数 ,并应用F值计算与术眼原晶状体屈光力等值的人工晶状体屈光度数 ,即等值人工晶状体屈光度数。应用SPSS统计软件对数据进行统计学分析。结果　低度近视患者3个公式计算结果LASIK手术前、后比较 ,差异均无显著意义 (P >0 0 5 ) ;中、高度近视患者 3个公式计算结果LASIK术后均小于术前 ,差异有显著意义 (P <0 0 1)。 3个公式计算的LASIK手术前、后等值人工晶状体屈光度数差值 (differenceofequalintraocularlenspower,EILD)均与LASIK实际矫正屈光度数呈高度相关性 (P <0 0 1)。回归公式 :EILD =a +b×手术实际矫正屈光度数 ,其中第二代经验公式 :a =- 1 2 3,b =0 72 ;第三代理论公式 :a =- 1 0 3,b =0 5 2 ;BinkhoistⅡ公式 :a =- 1 4 4 ,b =0 5 0。结论　对于中、高度近视患者 ,准分子激光屈光性角膜手术后使用现有人工晶状体屈光度数测算公式 ,其结果均偏小 ,应用EILD校正可提高准确性。对

Research on the forecast of intraocular lens power after excimer laser keratorefractive operation

OBJECTIVE: To study the accuracy of different formulas forecasting intracellular lens (IOL) power after excimer laser keratorefractive operation. METHODS: One hundred and twenty eyes (60 cases) underwent LASIK surgery. Before and after the surgery, the IOL powers were calculated to correct the myopia to emmetropia by experiential SRK II formula, theoretical SRK/T formula and Binkhoist II formula respectively. Then we calculated the IOL power equal to original lens power by F, and analyzed the results before and after surgery by SPSS statistical software. RESULTS: 1. The IOL powers were not obviously different by different formulas between pre-operative and post-operative results in low myopia (P > 0.05). In middle and high myopia there were obvious differences (P < 0.01), the postoperative results were smaller than the preoperative ones. 2. The differences of equal IOL power by different formulas were highly related to the practical corrective refractive values of the surgery. Regression formula: The difference of equal IOL power = a + b x the practical corrective refractive value of the surgery. (SRK II: a = -l.23, b = 0.72; SRK/T: a = -l.03, b = 0.52; Binkhoist II: a = -1.44, b = 0.5). CONCLUSION: The IOL powers forecasted by different formulas are smaller in middle and high myopia after excimer laser keratorefractive operation than that before the operation, and can be corrected by regression formula.