角膜屈光术后人工晶状体度数计算的临床观察

Clinic observation of intraocular lens power calculation after corneal refractive surgery

目的:探讨角膜近视屈光术后白内障患者的人工晶状体度数的计算方法,观察初步的临床效果。方法:回顾性分析2013-03/2015-06于我院行白内障手术同时伴有角膜近视屈光手术史的患者14例23眼。根据患者既往角膜手术方式分为LASIK(laser in situ keratomileusis)组9例15眼,RK(radial keratotomy)组5例8眼。将每例患者的角膜地形图中央2.5mm最低点曲率值,带入SRK-T公式,按照预留-1.00^-1.50D选择人工晶状体度数,完成常规的白内障超声乳化联合人工晶状体植入术。术后随访3mo,观察术后视力、矫正视力和屈光状态。计算出术后人工晶状体计算公式的预测屈光误差,分别与www.iolcalc.org网站上的Shammas公式和Barrett True K公式进行比较,观察其应用效果,采用独立样本t检验进行统计分析。结果:LASIK组和RK组相比,两组患者术后3mo的裸眼视力(LogM AR)分别是0.15±0.11、0.21±0.16,术后屈光度分别是-0.43±1.04、-1.52±1.01D,SRK-T公式预测屈光误差分别是-0.71±0.80、0.43±0.99,LASIK组均优于RK组且两组间差异均有统计学意义(P<0.05)。将本研究方法分别与Shammas公式和Barrett True K公式相比,观察各种公式的预测屈光误差,本研究方法的屈光误差最小,但是差异无统计学意义(P>0.05)。结论:应用研究方法的术后屈光状态均为轻度近视,适用于因近视行角膜屈光手术的白内障患者进行人工晶状体度数的选择,此方法对于LASIK手术史患者的人工晶状体度数预测性更佳。

AIM：To explore the method to calculate intraocular lens（IOL） power after corneal refractive surgery.METHODS：A retrospective study was conducted.Fourteen patients（23 eyes） with age-related cataract after corneal refractive surgery were treated in our hospital from March 2013 to June 2015.Patients were divided into LASIK group（laser in situ keratomileusis,9cases with 15 eyes） and RK group（radial keratotomy,5cases with 8 eyes）.Corneal curvature values of the lowest point in central 2.5mm were measured by corneal topography,which were used in SRK- T formula.Phacoemulsification with IOL implantation was performed with the target refraction was between-1.0^-1.5D.The patients were followed up for uncorrected visual acuity（UCVA）,best corrected visual acuity（BCVA） and refractive statuses at 3mo after the operations.The predictive error of the calculation formula were calculated and compared to Shammas formula and Barrett True K formula from www.iolcalc.org respectively.Statistical analysis of the data was performed using independentsamples t test..RESULTS：The UCVA（LogMAR） of LASIK group and RK group were 0.15±0.11,0.21 ±0.16 respectively,refractive status were-0.43±1.04,-1.52±1.01 D and the predictive errors of the SRK-T were-0.71 ±0.80,0.43±0.99 at 3mo after operations.There was significant differences（P〈0.05） between these two groups at all the three indicators,and those of the LASIK group were better,compared to those of RK group.The predictive errors of our observed method were better than those of the Shammas and Barrett True K formula,but there were no significant difference.CONCLUSION：Our results imply that using our observed method,the postoperatively predictive errors are mild myopia,which can be applied for determination of IOL power for cataract patients who received corneal refractive surgery.And it can improve accuracy of the intraocular lens power calculation for cataract patients with corneal myopic refractive surgery,especially for patients with LASIK.