激光原位角膜磨镶术后患者角膜总屈光力的评估及人工晶体屈光力的预测

Assessments of total corneal power and intraocular lens power in post-LASIK eyes

目的比较不同评估激光原位角膜磨镶术（LASIK术）后角膜屈光力的方法之间的差异；评估各角膜屈光力测算方法用于LASIK术后IOL度数预测的准确性和差异性。方法2011年2至9月浙江省温州医学院附属眼视光医院屈光手术中心接受LASIK手术且术后3个月来院复查患者39例71眼，按眼轴长度分为两组，A组（23．46～25．97mm）共44眼，B组（26．00～28．52mm）共27眼。术前等效球镜-1．75--9．50D，平均（-4．82±1．98）D，术前行主觉验光和Pentacam眼前节分析系统检查，术后3个月行主觉验光、IOLMaster和Galilei1I眼前房分析系统检查。通过GalileiⅡ获得模拟角膜屈光力SimK、基于高斯厚透镜公式的总屈光力K。和基于光线追击原理的总屈光力Kray，通过临床病史法获得Kchm，通过IOLMster获得Km。各K值联合Haigis、HofferQ、Holladay和SRK／T公式，IOLMaster自带Haigis-L公式预测LASIK术后眼人工晶体屈光力。重复测量方差分析比较SimK、Kn、Kray、Km与Kchm之间的差异，SimK、Kn、Kray、Km联合各IOL计算公式获得的IOL屈光力与Kchm联合各IOL计算公式的差异。Pearson相关分析各K值之间及各K值计算得出的IOL度数之间的相关性，P〈0．05为差异有统计学意义。结果（1）SimK、Kn、Kray、Km、Kchm分别为（39．0±1．8）D、（37．8±1．5）D、（36．8±1．8）D、（39．18±1．75）D、（38．55±1．83）D，SimK、Kn、Kray、Km与Kchm差异有统计学意义（P〈0．01）；SimK、Kn、Kray、Km和Krhm具有密切的相关性（r〉0．9，P^a〈0．01）。（2）同一种IOL屈光力预测公式中，Kray得到的IOL度数最大，Kn次之，Kchm第三，SimK和Km最小。（3）不同IOL屈光力预测公式之间，Haigis—L和Haigis公式得到的IOL度数最大，HofferQ次之，Holladay第三，SRK／T最小。结论Kray／Kn联合Haigis公式可能为预测LASIK手术后人工晶体屈光力的新的有效方法。

Objective To compare the different evaluations of corneal power in post- laser-assisted in situ keratomileusis（LASIK） eyes and assess the accuracy and differences of intraocular lens （IOL） power prediction with corneal powers through different calculation methods. Methods For this prospective study, 71 eyes of 39 candidates undergoing LASIK and 3 months later returning for reexamination were included. All subjects were divided into 2 groups according to the axial length： Group A （23.46 -25.97 mm） 44 eyes, Group B （26. 00 - 28.52 ram） 27 eyes. The ranges of spherical equivalents were - 1.75 - - 9.50 D with an average of （ - 4. 82 ± 1.98 ） D. Subjective refraction and Pentacam Scheimpflug analyzer were performed at pre-operation and subjective refraction, IOLMaster and Galilei I1 dual Seheimpflug analyzer at over 3 months post-operation. The following values were obtained： SimK by Galilei II dual Scheimpflug analyzer, Kn calculated with Gaussion thick lens formula, Kray with ray tracing method, Kchm calculated with clinical history method and Km by IOLMaster. Repeated measures analysis of variance analyze the differences between SimK, Kn, Kray, Km and Kchm employed to analyze the differences between SimK, Kn, Repeated measurement analysis of variance was Kray, Km combining intraocular lens power formula and Kchm combining intraocular lens power formula. Pearson＇s analysis was performed to analyze the correlations between SimK, Kn, Kray, Km and Kchm. Those combining with formulas for IOL power calculations were also analyzed. P 〈 0.05 indicated statistical significance. Results The values of SimK, Kn, Kray, KmandKchm were（39.02 ± 1.8）,（37.8 ±1.51）,（36.8 ±1.84）,（39.18 ±1.75）and （38.55 ± 1.83） D respectively. The differences between SimK, Kn, Kray, Km and Kchm had statistical significances （P 〈 0.01 ）. High correlations existed between SimK, Kn, Kray, Km and Kchm （r 〉 0.9, P 〈0.01 ）. In the same IOL formula, Kray had the highest IOL power value, Kn followed, Kchm the third, SimK and Km the smallest. Among the IOL formulas, Haigis-L and Haigis predicted the highest IOL power, HofferQ followed, Holladay the third and SRK/T the smallest. Conclusion Kn/Kray combining with Haigis formula may be a new and effective method for predicting the IOL power in post-LASIK eyes.