角膜屈光手术后人工晶状体度数的测算

角膜屈光手术后人工晶状体（IOL）度数的测算很复杂。按常规的测算方法,术后常会出现较大偏差。本文分析了角膜屈光手术后IOL度数测算的误差原因,并列出了多种解决策略,希望为该类患者IOL度数测算提供依据。（中华眼科杂志,2008,44：82-85）     

角膜屈光手术后人工晶状体度数计算公式的选择

角膜屈光手术后的患者发生白内障并行人工晶状体置换手术时,如果按常规计算公式选择人工晶状体的度数,往往会在术后产生不同程度的屈光不正,主要来源于角膜屈光力的测算误差和计算公式的误差,以及眼轴长度测量和有效人工晶状体位置计算的准确性降低等方面的原因.因此,对于曾行角膜屈光手术的白内障患者, 术前应运用适当的方法估算角膜屈光力,并正确地选择合适的人工晶状体度数计算公式,从而减少晶状体置换术后引起的屈光误差.     

角膜屈光手术后人工晶状体度数计算的初步研究

目的 对准分子激光角膜屈光手术后的白内障患者,分析其超声乳化白内障吸除联合人工晶状体(IOL)植入术后的屈光状态以及各种IOL度数计算方法的准确性.方法 回顾性系列病例研究.17例(24只眼)患者根据是否提供准分子激光术前(包括准分子激光角膜切削术和准分子激光角膜原位磨镶术)角膜屈光度数资料分为两组(有历史资料组和无历史资料组).所有患者在白内障术前接受自动角膜曲率计、角膜地形图、Pentacam、IOL Master综合检查,分别采用临床病史法、Feiz-Mannis公式法、Feiz-Mannis法等多种公式进行IOL度数计算.白内障术后3个月时进行客观验光.采用非配对t检验,Pearson相关分析及线性回归分析,配对t检验以及Bland-Ahman一致性检验对数据进行分析.结果 有历史资料组患者准分子激光术前的平均屈光度数与平均等效球镜分别为(43.28±1.21)D与(-15.33±4.36)D;无历史资料组的平均等效球镜为(-10.11±3.12)D.白内障术前两组平均角膜屈光度数为(36.96 ± 2.07)D与(36.85±1.40)D.白内障术后两组平均屈光误差分别为(-0.66±1.27)D与(-0.47 ± 0.82)D.Hamed Wang Koch法、Masket法、Koch/Maloney法、Shammar法与Pentacam ERK法计算值低于平均真实值,易造成术后欠矫;Feiz-Mannis公式法、Latkany法、Savini法与Armberri Double K的计算值高于真实值.临床病史法,角膜忽略法和Haigis-L法的计算值与真实值之间差异无统计学意义(P=0.364,0.318,0.069;t=0.956,-1.057,-1.911).Feiz-Mannis法和Haigis-L法计算结果与真实值之间具有一定相关性(r=0.921,0.915;P=0.000,0.000).但无一种方法计算结果与真实值具有一致性.结论 为避免术后发生屈光欠矫,需要通过综合方法计算IOL度数,应联合临床病史法、Feiz-Mannis法、角膜忽略法、Haigis-L法进行IOL度数计算.     

角膜屈光手术后人工晶状体度数计算的初步研究

Objective To evaluate the results of cataract surgery in myopia patients after laser in situ keratomileusis(LASIK)and to compare the predictability of various methods of intraccular lens(IOL)power calculation.Method Seventeen cases (24 eyes)who had LASIK for myopia were divided into two group by with or without history of corneal power data.Corneal power was obtained by autokeratometry,corneal topography.Pentacam and IOLMaster.The IOL power was calculated with the clinical history method,Feiz-Mannis formula,Feiz-Mannis method and other methods.Postoperative final refraction and the deviation of the final spherical equivalent (SEQ) from the refractive target were measured 3 month after the surgery.Two sample t-test.linear correlation and regression analysis,paired t-test and Bland-Altman method of agreement were used to analyze these data.Results In the group with history data,the mean corneal power was(43.28±1.21)D and the mean SEQ was(-15.33±4.36)D before the LASIK surgery.In the group without history data,the mean SEQ was(-10.11±3.12)D.Before cataract surgery,the mean corneal power was(36.96±2.07)D and(36.85±1.40)D in these two groups.The mean arithmetic refractive prediction error after cataract surgery was(-0.66±1.27)D and(-0.47 ± 0.82)D in these two groups, respectively. Data calculated by using Hamed-Wang-Koch method, Masket Formula, Koch/Maloney method, Shammar method and Pentacam ERK method were lower than the emmetropic IOL power. Data calculated by using Feiz-Mannis Formula, Latkany Method, Savini method, Armberri Double K method were overestimated. The mean arithmetic errors of clinic history method, Corneal Passby Method and Haigis-L Formula were not significantly different from the predict refraction (P=0. 364, 0. 318 and 0. 069;t=0. 956,-1. 057 and -1. 911, respectively). There was strong correlation between the value calculated by using Feiz-Mannis Method or Haigis-L Formula and the true power (r = 0. 921,0. 915; P = 0. 000 and 0. 000,respectively). But none of the values calculated by these method could fully agree with the true value.Conclusions IOL power should be calculated accurately to avoid undercorrection. We recommend the combination of clinical history method, Feiz-Mannis Method, Corneal Passby Method and Haigis-L Formula for the calculation of IOL power.     

角膜屈光手术后人工晶状体度数计算的初步研究

Objective To evaluate the results of cataract surgery in myopia patients after laser in situ keratomileusis(LASIK)and to compare the predictability of various methods of intraccular lens(IOL)power calculation.Method Seventeen cases (24 eyes)who had LASIK for myopia were divided into two group by with or without history of corneal power data.Corneal power was obtained by autokeratometry,corneal topography.Pentacam and IOLMaster.The IOL power was calculated with the clinical history method,Feiz-Mannis formula,Feiz-Mannis method and other methods.Postoperative final refraction and the deviation of the final spherical equivalent (SEQ) from the refractive target were measured 3 month after the surgery.Two sample t-test.linear correlation and regression analysis,paired t-test and Bland-Altman method of agreement were used to analyze these data.Results In the group with history data,the mean corneal power was(43.28±1.21)D and the mean SEQ was(-15.33±4.36)D before the LASIK surgery.In the group without history data,the mean SEQ was(-10.11±3.12)D.Before cataract surgery,the mean corneal power was(36.96±2.07)D and(36.85±1.40)D in these two groups.The mean arithmetic refractive prediction error after cataract surgery was(-0.66±1.27)D and(-0.47 ± 0.82)D in these two groups, respectively. Data calculated by using Hamed-Wang-Koch method, Masket Formula, Koch/Maloney method, Shammar method and Pentacam ERK method were lower than the emmetropic IOL power. Data calculated by using Feiz-Mannis Formula, Latkany Method, Savini method, Armberri Double K method were overestimated. The mean arithmetic errors of clinic history method, Corneal Passby Method and Haigis-L Formula were not significantly different from the predict refraction (P=0. 364, 0. 318 and 0. 069;t=0. 956,-1. 057 and -1. 911, respectively). There was strong correlation between the value calculated by using Feiz-Mannis Method or Haigis-L Formula and the true power (r = 0. 921,0. 915; P = 0. 000 and 0. 000,respectively). But none of the values calculated by these method could fully agree with the true value.Conclusions IOL power should be calculated accurately to avoid undercorrection. We recommend the combination of clinical history method, Feiz-Mannis Method, Corneal Passby Method and Haigis-L Formula for the calculation of IOL power.     

准分子激光屈光性角膜手术后白内障人工晶状体植入术

目的探讨准分子激光屈光性角膜手术后白内障吸出术中、植入人工晶状体的屈光度计算方法。方法对4例（4眼）准分子激光屈光性角膜手术后的白内障行超声乳化吸出及人工晶状体植入术，术前采用OrbscanⅡ角膜地形图及角膜曲率计测量角膜的K值，分别应用第二代经验公式（SRKⅡ）计算所需人工晶状体的屈光度。术后验光记录术眼屈光状况，与术前结果对比，评价所选择的人工晶状体屈光度的准确性。结果OrbscanⅡ角膜地形图和角膜曲率计分别测量的角膜K值，以及所计算的人工晶状体的屈光度，均有明显的差别。尽管按预留近视状态，选用角膜地形图测量的K值计算人工晶状体的屈光度，术后仍然欠矫，平均产生远视＋1．57D，较术前预留度数仍相差约＋3．44D。结论采用OrbscanⅡ角膜地形图的K值来计算人工晶状体屈光度误差小，在预留的屈光度数基础上加3．50D来选择人工晶状体是较为精确和安全的。     

角膜屈光手术后人工晶状体植入度数的计算

目的分析应用 HolladayⅡ公式计算角膜屈光手术后人工晶状体(IOL)植入度数的准确性。方法角膜屈光手术后患者15例(15只眼),分成两组行超声乳化白内障吸除术联合 IOL 植入术。第一组(8只眼)应用 HolladayⅡ公式进行 IOL 度数计算,角膜屈光度根据手术医师经验计算获得,为 KS。第二组(7只眼)应用同一公式,但角膜屈光度应用患者的屈光度数计算获得,为 KR。比较超声乳化白内障吸除术后1个月的屈光度数与术前的预期屈光度数,并应用两者差的绝对值作为标准进行分析。结果两组超声乳化白内障吸除术后1个月的角膜屈光度数与术前预期屈光度数差的绝对值平均值依次为(0.90±0.22)D 和(0.99±0.22)D。结论应用 HolladayⅡ公式计算角膜屈光手术后行超声乳化白内障吸除术时植入 IOL 度数的准确性相对较高。KS 与 KR 在 HolladayⅡ公式中应用的差异无统计学意义。(中华眼科杂志,2006,42:888-891)     

角膜屈光手术后人工晶状体度数计算

自上世纪80年代以来,角膜屈光手术在矫正屈光不正方面取得了很大进展,首先是角膜放射状切开手术治疗了大量的近视眼患者,90年代后逐渐被准分子激光手术(photorefrective keratectomy,PRK)和准分子激光原位角膜磨镶术(laser in situ keratomileusis,LASIK)所取代,随着年龄的增加这些患者已逐步发生白内障并且需要手术治疗.这些白内障手术操作与普通白内障手术相比并无多大区别,但人工晶状体的度数计算却是个难题.近视眼尤其是高度近视的白内障患者由于眼球解剖结构异常,人工晶状体(Intra OcularLens,IOL)度数计算误差就较大,角膜屈光手术改变了角膜的解剖结构,按曲率计或角膜地形图测定角膜屈光度、眼轴长度以及传统人工晶状体公式计算出的度数,在IOL植入术后普遍会出现不同程度的远视,据报道最高远视度数可高达 10D.这是由于目前的角膜屈光度测量都是基于Gullstrand's模型眼计算的,在眼球角膜结构发生较大改变时,这些计算公式无法表达出来,从而导致错误.目前已有一些比较成功的校正方法用于克服此类计算误差,本文就这一些方法及进展并结合自己的临床经验围绕计算公式及计算公式中主要参数角膜屈光度重估等为重点进行介绍和讨论.     

角膜屈光手术后的人工晶状体度数计算

角膜屈光手术后用现行的角膜曲率检测方法测量角膜屈光力不精确,导致该类患者白内障手术时人工晶状体度数计算偏低,术后呈较严重的远视状态。随着接受准分子激光角膜屈光手术人数的增加,此问题在未来将日益突出。围绕这一问题,不少学者提出多种修正方案,以期提高角膜屈光手术后人工晶状体度数计算的准确性,本文就此进行综述。     

角膜屈光手术后人工晶状体度数的测算

目的评价Pentacam等效角膜屈光力（EKR）代入Holladay I公式联合双K法测算角膜屈光手术后人工晶状体（IOL）度数的准确性。方法回顾性系列病例研究。收集既往有准分子激光角膜屈光术史白内障患者32例（45眼）,所有患者在白内障术前接受Pentacam、IOLMaster检查,分别采用Pentacam EKR法、临床病史法、Haigis-L公式法计算IOL度数。白内障术后1个月进行客观验光,采用Kruskal-Wallis秩和检验和单因素方差分析比较术后屈光度的中值绝对偏差（MedAE）、平均绝对偏差（MAE）。结果Pentacam EKR代入Holladay I公式联合双K法得出MedAE为0.32 D,MAE为0.39 D,术后71%眼屈光误差在±0.50 D范围内,93%眼在±1.00 D范围内,而Haigis-L公式法得出MedAE为0.51 D,临床病史法MedAE为1.48 D。结论Pentacam EKR代入Holladay I公式联合双K法测算角膜屈光手术后IOL屈光度数比较准确。     

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     

准分子激光原位角膜磨镶术后人工晶状体度数的计算方法

目的 验证准分子激光原位角膜磨镶(LASIK)术后人工晶状体度数的有效测量方法.方法 回顾性系列病例研究.收集在香港养和医院行LASIK手术8年或3个月后因白内障形成而行白内障超声乳化吸除术的患者28例(40只眼).利用临床既往数据计算得出K(K1)值以及由IOLmaster人工晶状体测量仪所测得K(K2)值,将K值输入SRK/T公式得出人工晶状体的度数.用K1与用K2预测术后屈光度组间比较采用配对t检验,用K1预测术后屈光度与术后3个月时实际屈光度组间比较采用秩和检验.结果 患者眼轴长度为(24.28～31.96)mm,平均为(28.06±1.98)mm.LASIK手术前的初始屈光度数(球镜当量)为(-3.13～-18.00)D,平均为(-10.44±3.93)D;K值为(41.40～46.90)D,平均为(43.57±1.47)D.最佳矫正视力:19只眼为1.0,10只眼为0.8,7只眼为0.6,4只眼为0.5.LASIK术后6个月的平均屈光度数(球镜当量)为(-2.83～+1.25)D,平均为(-0.32±0.95)D.超声乳化白内障吸除术前的平均屈光度数(球镜当量)为(-5.75～+1.13)D,平均为(-2.35±2.16)D.根据临床既往数据计算所得的K1平均值(KpreLASIK+RpreLASIK-RpostLASIK)为(27.60～40.70)D,平均为(34.62±3.56)D,由IOLmaster人工晶状体测量仪所测得的K2值为(32.39～43.53)D,平均为(38.04±2.45)D,两者间比较差异有统计学意义(t=-7.68,P=0.00).由K1值测得的人工晶状体度数的术后预计平均屈光度数(球镜当量)为(-3.69～0.61)D,平均为(-1.32±1.00)D;而由K2值测得的则为(-3.67～3.95)D,平均为(-0.60 ±1.84)D,两者差异有统计学意义(t=-2.40,P=0.02).超声乳化白内障吸除术后的平均屈光度数(3个月以上)为(-4.50～+1.75)D,平均(-1.10 ±1.51)D,与K1值测得的人工晶状体度数的术后预计平均屈光度数比较,两者差异无统计学意义(Z=1.20,P=0.23).超声乳化白内障吸除术后最佳矫正视力:20只眼为1.0,9只眼为0.8,5只眼为0.6,6只眼为0.5.结论 本研究所使用的人工晶状体度数的计算公式是准确而可行的.     

Intraocular lens power calculation after keratorefractive surgery

The number of keratorefractive procedures designed to correct refractive errors has dramatically increased over the last few years. The techniques for cataract extraction and intraocular lens implantation have evolved into a refractive surgical procedure as well as an operation to improve best corrected visual acuity and/or spectacle independence. The calculation of intraocular lens power for a desired refractive target can be challenging in post-refractive surgically treated eyes, given the frequent case reports of "refractive surprises" after cataract surgery. After corneal refractive surgery, the direct use of the measured topographic or keratometric values, with no correction, results in less accurate calculation of intraocular lens (IOL) power required for cataract surgery than calculation in virgin eyes. After laser refractive surgery for myopia, this could result in an overestimation of the corneal power and subsequent underestimation of the IOL power, therefore leading to a hyperopic outcome after phacoemulsification. Conversely, after laser refractive surgery for hyperopia, inaccuracy in the keratometric power estimation could result in a myopic outcome after phacoemulsification. Despite current progress in this subject, awareness of the shortcomings of classical methods and suggested strategies to improve accuracy can be valuable to clinicians. This article provides an overview of the possible sources of error in intraocular lens power calculation in post-keratorefractive patients, and reviews the methods to minimize intraocular lens power errors.     

光学虹膜切除术后先天性白内障摘除人工晶状体植入联合瞳孔成形术

目的：探讨光学虹膜切除术后治疗先天性绕核性白内障的方法。方法：对光学虹膜切除术后的先生性绕核性白内障患者12例（24只眼）行软性白内障摘除囊袋人工晶状体植入联合瞳孔成形术,术中采取角膜进针、穿过缺损区域两侧虹膜、角膜出针、通过白内障切口行前房内打结方法恢复瞳孔形状。结果：全部患者术后矫正视力均≥0．5,瞳孔近似圆形,且对光反射存在;无畏光和单眼复视症状;美容效果良好。结论：白内障摘除人工晶状体植入联合瞳孔成形术是治疗光学虹膜切除术后先天性绕核性白内障患者的理想方法。     

应用优化计算方法与计算机软件计算角膜屈光手术后人工晶状体屈光力

目的 对准分子激光角膜屈光手术后人工晶状体屈光力的计算方法进行优化,并开发为计算机软件,评价其准确性与可靠性.方法 对人工晶状体屈光力计算方法进行优化,包括：角膜屈光力的矫正计算 人工晶状体有效位置的计算与双K值法（double-K method）的应用 标准化计算公式的应用.将计算方法编写为计算机应用软件（IOL calculator for post-refractive cases）.应用该软件对49例角膜屈光手术后的白内障患者的人工晶状体屈光力进行计算,以白内障手术后实际屈光状态为标准,预测屈光状态与实际屈光状态之间的差异为预测误差,预测误差的绝对值为绝对预测误差.以SPSS 11.0软件分析预测误差与绝对预测误差的平均值与分布.结果 白内障手术后屈光状态为-2.50～0.75 D,平均为（-0.78±o.83）D,3眼（6.1%）为正视,36眼（73.5%）为近视,10眼（20.4%）为远视.预测误差为-1.26～1.96 D,平均（-0.02±0.75）D,接近于正视性屈光状态.绝对预测误差为0～1.96 D,平均（0.62±0.42）D,绝对预测误差≤0.5 D者19眼（38.8%）,＞0.5 D且≤1.0 D者22眼（44.9%）,＞1.0 D且≤1.5 D者7眼（14.3%）,＞1.5 D 且≤2.0 D者1眼（2.0%）.结论 通过优化计算方法与开发计算机软件,可以充分简化准分子激光角膜屈光手术后人工晶状体屈光力的计算过程,并提高计算的准确性与可靠性.