飞秒激光和角膜板层刀制瓣准分子激光原位角膜磨镶术的临床效果

目的 比较应用飞秒激光和角膜板层刀制瓣准分子激光原位角膜磨镶术(LASIK)的临床效果.方法 回顾性分析400例(800眼)近视手术,根据制作角膜瓣方法不同分为两组,每组均为200例(400眼),组1为飞秒激光(Intralase FS60 kHz)制作角膜瓣,组2为Moria M2 90号板层刀制瓣.两组均在Wavescan波前引导下VISX Star S4准分子激光进行基质层切削.术后3个月、6个月行视力、屈光状态、波前像差等检查.结果 术后3个月、6个月两组视力和屈光度比较差异无统计学意义(P＞0.05).术后3个月,组2总高阶像差、彗差、球差高于组1,两组差异有统计学意义(P＜0.05),三叶草像差比较差异无统计学意义(P＞0.05).术后6个月,组2总高阶像差、彗差、球差、三叶草像差均高于组1,两组差异有统计学意义(P ＜0.05).结论 应用飞秒激光和角膜板层刀制瓣LASIK术是矫正近视安全有效的方法,在提高视觉质量和安全性方面飞秒激光优于角膜板层刀制瓣LASIK术.     

应用Femto LDV飞秒激光制瓣的准分子激光原位角膜磨镶术

目的 探讨用Zeimer Femmto LDV飞秒激光制作角膜瓣准分子激光原位角膜磨镶术(LASIK)的安全性和效果.方法 同期行LASIK治疗的近视198例(396眼).根据角膜瓣制作方法分为两组:Ⅰ组120例(240眼)用Zeimer Femto LDV飞秒激光制作角膜瓣,Ⅱ组78例(156眼)用Moria M2 90 μm机械刀制作角膜瓣,比较两组术后1d、1个月、6个月裸眼视力、最佳矫正视力、屈光度及高阶像差.结果 两组角膜瓣制作都顺利;术后不同时间,两组的裸眼视力、最佳矫正视力的差异无统计学意义;术后1个月、6个月两组的屈光度比较,球镜的差异无统计学意义,但Ⅰ组的残余散光低于Ⅱ组,差异有统计学意义;术后6个月,两组的总高阶像差、慧差、球差都较术前增加,但Ⅰ组的总高阶像差和慧差的增加少于Ⅱ组,差异有统计学意义.结论 Femto LDV飞秒激光制瓣的LASIK与机械刀制瓣LASIK相比,术后视力无差别,但术后残余散光低,总高阶像差、慧差增加较少,视觉质量可能优于后者.     

飞秒激光联合LASIK术后视觉质量的变化

目的：对比飞秒激光制瓣的准分子激光原位角膜磨镶术( femtosecond-laser in situ keratomileusis, femto-LASIK )与传统机械板层刀制瓣的准分子激光原位角膜磨镶术( laser in situ keratomileusis,LASIK)治疗屈光不正患者术后视觉质量的变化。
　　方法：回顾性病例研究。选择我院2014-01/2015-12进行屈光手术的患者89例178眼,其中使用飞秒激光制作角膜瓣患者46例92眼,使用显微角膜板层刀制作角膜瓣患者43例86眼。术后随访6mo,观察患者的视力、屈光状态、主观视觉质量评分、高阶像差等情况。
　　结果：所有患者均顺利完成手术,角膜瓣均制作成功,无术中及术后并发症发生。两组患者术后不同时间裸眼视力与术前最佳矫正视力相比较,差异无统计学意义(P>0.05),两组患者术后屈光度与术前预期屈光度比较,差异具有统计学意义(P<0.05)。两组患者术后6mo主观视觉调查质量评分比较,差异有统计学意义(P<0.05)。术后6 mo飞秒激光组和机械板层刀组角膜像差均方根值、球差及彗差较术前增加,差异具有统计学意义(P<0.05),但飞秒激光组增加的幅度比机械板层刀组低,差异有统计学意义(P<0.05)。
　　结论：飞秒激光制作角膜瓣更精确可靠,离散度更小,可以制作更薄的角膜瓣,飞秒激光制瓣的LASIK较传统机械板层刀LASIK术后可以获得更好的视觉质量。     

使用飞秒激光刀制作角膜瓣行LASIK的像差分析

目的 比较飞秒激光刀与普通自动角膜板层刀制作角膜瓣行准分子激光原位角膜磨镶术（LASIK）后眼球的像差变化.方法 将行LASIK的患者21例42眼分别使用飞秒激光刀（16眼）与普通自动角膜板层刀（26眼）制作角膜瓣后,在同一机型下行激光切削,术后10 d、1个月、3个月分别对两组患者的像差进行分析.结果 角膜板层刀组高阶像差较术前增加,飞秒激光组高阶像差较术前减少,两组的高阶像差具有统计学意义（P＜0.05）;两组的球差均较术前增加,而自动角膜板层刀组球差增加明显高于飞秒激光组,差异有统计学意义（P＜O.05）.结论 使用飞秒激光刀制作角膜瓣行LASIK在一定程度上可抑制手术造成的像差增加,对提高LASIK术后的视功能具有重要意义.     

飞秒激光和显微板层刀行LASIK手术后视觉质量比较

目的:比较飞秒激光和角膜板层刀制瓣准分子激光原位角膜磨镶术(laser in situ keratomileusis,LASIK)的视觉质量。方法:回顾性系列病例研究。选取2011-06/09我院完成的LASIK手术病例150例300眼,根据制瓣方式分为飞秒激光组和板层刀组各75例150眼,所有手术均采用EC5000CX-Ⅱ(日本Nidek公司)行基质切削,且都由同一手术医师完成。比较两组患者术前及术后1wk;1,3mo的裸眼视力(uncorrected visual acuity,UCVA)、屈光度、术后最佳矫正视力(best corrected visual acuity,BCVA)、波前像差及明视和暗视状态下的对比敏感度。结果:术后1wk;1,3mo两组患者的UCVA和屈光度(等效球镜)比较差异均无统计学意义。在术后1mo时,飞秒组C7的绝对值、RMSh,RMS3和RMS6值均低于板层刀组(P<0.05);术后3mo时飞秒组C7的绝对值、C14和RMS6的值均显著低于板层刀组(P<0.05)。明视和暗视对比敏感度在术后1wk时,飞秒组和板层刀组均较术前降低,差异均有统计学意义(P<0.05)。术后1mo时,明视和暗视对比敏感度较术后1wk有所提高,至术后3mo略高于术前水平,差异无统计学意义(P>0.05)。结论:飞秒激光制作角膜瓣的LASIK手术在治疗近视和散光方面具有安全性、有效性的特点。飞秒激光在提高UCVA的同时,还能减少高阶像差的产生,并且不会导致术后对比敏感度的下降,能够提高了患者的视觉质量。其术后效果优于角膜板层刀制作角膜瓣的LASIK手术。     

角膜波前像差引导的个性化LASIK和常规LASIK治疗近视的临床研究

目的比较常规准分子激光原位角膜磨镶术（Laser in situ Keratomileusis，LASIK）和角膜波前像差引导的个性化准分子激光原位角膜磨镶术（corneal wavefront aberrations guidedL ASIK，CW-GLASIK）治疗近视眼术后患者视觉质量的变化，探讨角膜波前像差引导的个性化准分子激光原位角膜磨镶术对对比敏感度和眩光以及角膜波前像差的影响，评价其手术的有效性。方法选取拟做LASIK手术的近视眼患者（近视球镜≤-10．00D，散光≤-2．5D）随机分成两组，一组行常规LASIK手术，另一组行角膜波前像差引导的个性化LASIK手术，手术均采用德国Schwind公司Esiris’准分子激光治疗系统，微角膜刀采用Moria LSK-ONE气动平推刀，对比敏感度检查采用Vector Vision CSV-1000HGT，角膜波前像差分析采用德国OPTIKON 2000 Keratron Scout分析仪。手术光学区直径为（6．0-7．0）mm，波前像差分析为6mm瞳孔直径。术前、术后检查裸眼视力、屈光度、对比敏感度及角膜地形图并进行波前像差分析。结果术后两组的裸眼视力均达到术前矫正视力，无显著性差异（P〉0．05）。两组术后1m时对比敏感度及眩光和术前比较均明显下降，差异有显著性（P〈0．05），术后3m时各空间频率对比敏感度和眩光均有所恢复，但均未达到术前水平，角膜波前像差引导的个性化LASIK组在各空间频率的对比敏感度和眩光同术前比较，无显著性差异，LASIK组在各空间频率的对比敏感度和眩光和术前比较差异有显著性（P〈0．05），角膜波前像差引导的个性化LASIK组在中（6c／d）、高（12c／d、18c／d）空间频率的对比敏感度和眩光明显好于常规LASIK组，有显著性差异（p〈0．05）。两组术后1m、3m角膜彗差、球差均比术前增大，但角膜波前像差引导的个性化LASIK组较常规LASIK组增大幅度小，差异有统计学意义（P〈0．05）。结论角膜波前像差引导的LASIK手术能有效地矫正近视，改善近视眼患者术后对比敏感度，降低术后彗差和球差，手术效果稳定、安全。     

飞秒激光角膜屈光手术后视觉质量

目前飞秒激光在角膜屈光手术的应用主要有两类,飞秒激光制作角膜瓣联合基质面行准分子激光切削(FS-LASIK)以及全飞秒激光手术;后者可分为飞秒激光基质透镜切除术(FLEx)和飞秒激光小切口基质透镜切除术(SMILE).本文回顾了与传统LASIK相比,FS-LASIK手术后裸眼视力、矫正视力、安全指数、有效指数的差别,FS-LASIK术后对比敏感度、高阶像差等客观视觉质量以及主观视觉质量问卷的影响;与FS-LASIK相比,FLEx对术后裸眼视力、波前像差等客观视觉质量以及主观满意的影响;并对三种手术方式的术后的安全性、有效性、可预测性以及在角膜知觉方面的优缺点进行综述.     

Q值引导的飞秒激光与机械板层刀制瓣的SBK术后视觉质量比较

目的比较Q值引导的机械板层刀制瓣的前弹力层下角膜磨镶术（OUP-SBK）和飞秒激光制瓣的SBK（Femto-SBK）2种手术方式矫治高度近视患者后的视觉质量。方法前瞻性队列研究。筛选丽水市中心医院近视激光中心2013年6月至2015年1月间收治的高度近视患者110例（220眼）,根据制瓣方式分为Femto组55例（110眼）,OUP组55例（110眼）,分别行Q值引导的飞秒激光与机械板层刀制瓣的SBK术矫治高度近视。测量2种术式中制作的角膜瓣厚度及术后1 d、1周、1个月、3个月、6个月的视力、残余屈光度、总高阶像差、球差、水平彗差、垂直彗差、对比敏感度等指标。数据采用t检验及重复测量资料的方差分析进行比较。结果术后1、3、6个月,2组间患者的裸眼视力、屈光度、垂直彗差增幅、对比敏感度差异无统计学意义（P＞0.05）。术中Femto组制作的角膜瓣厚度与预设差值小于OUP组（t=24.45,P＜0.01）,且总高阶像差、球差、水平彗差增幅均小于OUP组（t=12.87、7.12、7.26,P＜0.01）。结论与机械板层刀制瓣的SBK相比,飞秒激光制瓣的SBK术治疗高度近视时引出的像差更小,可能可以提供相对更好的视觉质量。     

飞秒激光与微型角膜刀制瓣LASIK术后视觉质量比较

背景 准分子激光角膜原位磨镶术(LASIK)是目前矫正近视和近视散光的主要手术方式之一,研究表明飞秒激光制瓣LASIK的安全性、精确性及可预测性明显优于微型角膜刀制瓣LASIK,但飞秒激光制瓣LASIK对患者视觉质量的影响仍是关注的焦点. 目的 比较Intralase FS60飞秒激光和Moria M2微型角膜刀制瓣LASIK矫正屈光不正的临床疗效及术后视觉质量. 方法 采用前瞻性非随机临床对照研究方法,纳入2012年3-8月于首都医科大学附属北京同仁医院拟行LASIK治疗近视及近视散光并符合纳入标准的患者共102例204眼.根据自愿的原则将患者分为2个组,各组患者基线特征匹配.飞秒激光制瓣组50例100眼行飞秒激光制瓣的LASIK,微型角膜刀制瓣组52例104眼行微型角膜刀制瓣的LASIK.分别于术前及术后3个月、6个月和1年采用波前像差仪分析6 mm瞳孔下Zernike系数及高阶像差的均方根值,采用Optec 6500视功能测试仪测定暗视及暗视+眩光状态下1.5、3.0、6.0、12.0和18.0 c/d空间频率的对比敏感度(CS).结果 飞秒激光制瓣组术后3个月、6个月和1年裸眼视力达到及超过术前最佳矫正视力(BCVA)者分别占95.1％、94.2％和93.9％,微型角膜刀制瓣组分别为94.2％、93.8％和93.2％.术前、术后3个月和术后1年,飞秒激光制瓣组等效球镜度(SE)分别为(-6.37±2.12)、(-0.26±0.45)和(-0.45±0.51)D,微型角膜刀制瓣组分别为(-6.25±2.05)、(-0.44±0.64)和(-0.35±0.59)D,术后3个月和1年2个组间SE比较差异均无统计学意义(u=l.194、1.429,均P＞0.05).术后3个月、6个月及1年飞秒激光制瓣组总高阶像差(RMSh)及各项高阶像差均明显低于微型角膜刀制瓣组(均P＜0.05).术后3个月和6个月飞秒激光制瓣组术眼在暗视及暗视+眩光状态下各空间频率的LogCS值均明显优于微型角膜刀制瓣组,差异均有统计学意义(均P＜0.05).术后1年,2个组间术眼在暗视状态下1.5 c/d空间频率的LogCS差异无统计学意义(P＞0.05),而飞秒激光制瓣组术眼在暗视及暗视+眩光状态下12.0 c/d和18.0 c/d空间频率的LogCS值均明显优于微型角膜刀制瓣组,差异均有统计学意义(均P＜0.05). 结论 飞秒激光制瓣的LASIK术后产生的高阶像差低于微型角膜刀制瓣的LASIK,视觉质量优于微型角膜刀制瓣的LASIK.     

飞秒激光和角膜板层刀制瓣LASIK术后临床效果的比较

目的：观察飞秒激光和角膜板层刀制瓣准分子激光原位角膜磨镶术(LASIK)术后的临床疗效。

方法：对本院眼视光中心行飞秒激光和角膜板层刀制瓣LASIK术的近视患者各50例100眼在术后1、3、6mo做裸眼视力、残余屈光度、干眼症调查、高阶像差检查。

结果：两组的裸眼视力及残留屈光度在术后6mo内差异均无统计学意义(P>0.05); 干眼症状调查显示：术后1、3mo,两组比较差异均有统计学意义(P<0.05); 术后6mo两组比较,差异无统计学意义(P>0.05); 两组术后1、3、6mo高阶像差与术前对比均增大,差异有统计学意义(P<0.05),两组术后1mo水平彗差、垂直彗差及球差之间差异均无统计学意义(P>0.05); 两组术后3、6mo水平彗差、垂直彗差之间差异均无统计学意义(P>0.05),但飞秒激光制瓣LASIK术球差变化值小于角膜板层刀制瓣LASIK术,差异有统计学意义(P<0.05)。

结论：飞秒激光制瓣LASIK术是一种安全、有效、稳定的手术方式,干眼症发生率低,术后视觉质量更优于角膜板层刀制瓣LASIK。     

不同方式角膜准分子激光手术对人眼波前像差的影响

目的研究不同方式的角膜准分子激光手术(LASIK、LASEK)对术后高阶像差的影响。设计病例对照研究。研究对象行LASIK及LASEK患者各22例(各43眼)。方法对行LASIK或LASEK的患者术前、术后1、3、6个月进行波前像差检查。主要指标视力、屈光、波前像差的变化。结果两种手术方式的术后视力与等效球镜度相近。6mm瞳孔直径下,术后1个月时,总波前像差的RMS值比术前减少61%,高阶像差增加110%。术后高阶像差的主要成分大部分增加;其中,球差增加最大,1个月时比术前增加285%。术后1、3个月,LASIK术式组高阶像差RMS值稍低于LASEK术式组;术后6个月,LASIK术式组高阶像差RMS值稍高于LASEK术式组(P>0.05)。其中,两组的三阶彗差、三叶草、球差RMS值改变无统计学意义(P>0.05)。结论LASIK与LASEK患者术后视力与屈光结果相近。术后总波前像差和低阶像差降低,高阶像差增加。不同手术方式对术后高阶像差无显著性影响。(眼科,2006,15:191-194)     

Randomized prospective clinical study comparing induced aberrations with IntraLase and Hansatome flap creation in fellow eyes: potential impact on wavefront-guided laser in situ keratomileusis

PURPOSE: To measure and compare the changes in objective wavefront aberration and subjective manifest refraction after laser in situ keratomileusis (LASIK) flap creation with a mechanical microkeratome and a femtosecond laser. SETTING: Private practice refractive surgery center, Irvine, California, USA. METHODS: This randomized prospective study comprised 9 patients (18 eyes) treated with a 2-step LASIK procedure: lamellar keratectomy with a Hansatome microkeratome (Bausch & Lomb) or the IntraLase femtosecond laser in fellow eyes followed by non-wavefront-guided (standard) excimer laser treatment with the Technolas 217A (Bausch & Lomb) excimer laser 10 weeks later. Fellow eyes were matched to within 0.75 diopter (D) sphere and 0.50 D cylinder. Patients were followed for 3 months after excimer laser treatment. Preoperative and post-flap creation wavefront aberrometry using a Hartmann-Shack aberrometer and manifest refraction were compared between the 2 groups. The same tests were performed 3 months after excimer laser ablation. RESULTS: Statistically significant changes were seen in defocus wavefront aberrations after Hansatome (P=.004) and IntraLase (P=.008) flap creation. A hyperopic shift in manifest refraction was noted in the Hansatome group after the creation of the corneal flap (P=.04); no statistically significant changes in manifest refraction were seen in the IntraLase group. Statistically significant changes in total higher-order aberrations (HOAs) (trefoil and quadrafoil Zernike terms) were seen after flap creation in the Hansatome group (P=.02). No significant changes in HOAs were noted after flap creation in the IntraLase group. After the flap was relifted and standard excimer laser ablation was performed, a statistically significant increase in coma occurred in the Hansatome group (P=.008). Standard refractive outcomes in the 2 groups were similar. CONCLUSIONS: The creation of the LASIK flap alone can modify the eye's optical characteristics in low-order aberrations and HOAs. A significant increase in HOAs was seen in the Hansatome group but not in the IntraLase group. This may have significant clinical implications in wavefront-guided LASIK treatments, which are based on measurements made before flap creation.     

Visual performance after conventional LASIK and wavefront-guided LASIK with iris-registration:results at 1 year

AIM: To compare visual performance of wavefront-guided laser in situ keratomileusis (LASIK) with iris-registration (Wg-LASIK group) and conventional LASIK (LASIK group) one year after surgery and analyze the correlation between wavefront aberrations and visual performance.METHODS: Eight hundred and fifty-two myopic eyes of 430 patients were enrolled in this prospective study and divided into two groups:Wg-LASIK group (436 eyes) and LASIK group (416 eyes). A Wavescan Wavefront aberrometer was used to analyze Zernike coefficients and the root-mean-square (RMS) of higher order aberrations, and Optec 6500 visual function instrument was used to measure contrast sensitivity (CS) before and 3, 6, 12 months after surgery.RESULTS:The mean spherical equivalent (SE) in Wg-LASIK group was significantly better than those in LASIK group one year after surgery (P=0.024). Wg-LASIK eyes showed better CS values than LASIK eyes at all spatial frequencies with and without glare after surgery (P all<0.01). Moreover, the increase of higher RMS (RMSh), coma, RMS3, RMS4, RMS5 in Wg-LASIK group were significantly lower than those in LASIK group 1 year after surgery (P all<0.05). The increase of coma, spherical aberration (SA), RMS3 and RMS4 in Wg-LASIK and coma and RMS3 in LASIK group were negatively correlated with reduction of contrast sensitivity 1 year after surgery.     

Wavefront-guided laser in situ keratomileusis: early results in three eyes

PURPOSE: Wavefront optical aberrations induced by refractive corneal surgery correction of myopia are probably the reason for deterioration of visual performance in some eyes after surgery. Customized photoablation of the cornea to correct both the sphero-cylindrical refractive error as well as individual optical aberrations may improve postoperative visual acuity and visual performance. METHODS: In 3 eyes of 3 patients the wavefront deviations were measured by means of an aberrometer of the Tscherning-type. Based on these measurements an ablation pattern was determined and applied during a LASIK procedure using a Wavelight Allegretto scanning spot excimer laser with a spot size of 1 mm and a laser repetition rate of 200 Hz. The 3 eyes are part of a prospective study on wavefront-guided LASIK started in July 1999. RESULTS: At 1 month after LASIK, all 3 eyes had gained up to 2 lines of best spectacle-corrected visual acuity. Best spectacle-corrected visual acuity improved to 20/10 in all 3 eyes, uncorrected visual acuity was 20/10 in two eyes, and 20/12.5 in 1 eye 1 month postoperatively. The wavefront deviations were reduced by 27% on average. At 3 months, best spectacle-corrected visual acuity was 20/10 in 2 eyes and 20/12.5 in 1 eye. CONCLUSION: Wavefront-guided LASIK is a feasible approach in refractive corneal surgery. Optimized ablation patterns may further improve the visual results.     

飞秒激光制作角膜瓣的激光角膜原位磨镶术的临床观察

目的探讨应用飞秒激光制作角膜瓣的准分子激光角膜原位磨镶术（LASIK）的安全性、有效性和可预测性。方法应用VISX Stars 4准分子激光设备和Intralase飞秒激光仪,对屈光不正512例（1016眼）施行飞秒激光制作角膜瓣的LASIK手术。术后随访6～12个月,裂隙灯显微镜及角膜地形图仪检查角膜及角膜屈光改变情况。结果术后6个月的屈光状态,（等效球镜）为（1．00D～＋1．25D）,平均为（-0．25±0．75D）。923眼（90．85％）的裸眼视力大于或等于1．0,1002眼（98．62％）的裸眼视力等于或超过术前最佳矫正视力。术前与术后结果行t检验显示,二者差异有统计学意义（P〈0．01）。术中并发症有结膜下出血57眼（5．61％）,未见其他并发症。结论应用飞秒激光制作角膜瓣的LASIK手术是矫正屈光不正的安全和有效的方法,可预测性好。     

激光上皮下角膜磨镶术治疗高度近视远期对比敏感度的研究

目的:研究激光上皮下角膜磨镶术(laser epithelial keratom ileusis,LASEK)治疗高度近视的远期对比敏感度的改变,并评价LASEK治疗高度近视的安全性及有效性。方法:回顾性分析比较LASEK和激光原位角膜磨镶术(laser in situ keratom ileusis,LASIK)治疗高度近视各30眼的临床资料,LASEK和LASIK均采用美国产BAUSCH&LOMB公司的TECHNOLS217c型准分子激光治疗仪进行激光切削,术后随访3mo,对术后haze、屈光状态和对比敏感度进行分析比较。所有患者年龄分布在18～30岁,术前最佳矫正视力均≥0.8,所有病例均无其他任何影响对比敏感度的眼疾,亦无其它可能会影响对比敏感度的全身性疾病。结果:比较术后3mo时LASEK和LASIK两组的haze发生率,差异无显著性(P>0.05)。两组术后的屈光度值,差异无显著性(P>0.05)。两组术后各空间频率的对比敏感度,差异无显著性(P>0.05)。结论:准分子激光上皮下角膜磨镶术在治疗高度近视时,可产生很好的远期疗效,手术安全性高。     

Measurement of corneal curvature change after mechanical laser in situ keratomileusis flap creation and femtosecond laser flap creation

PURPOSE: To compare the change in corneal curvature from the predicted surgical radius (sculpted in the corneal stroma) and the measured postoperative radius of the first surface of the cornea after laser in situ keratomileusis (LASIK) for myopia correction using 2 methods of flap creation: mechanical microkeratome and femtosecond laser. SETTING: Vissum-Instituto Oftalmológico de Alicante, Alicante, Spain. METHODS: This retrospective consecutive nonrandomized comparative interventional case series included 85 eyes with myopia or myopic astigmatism treated using the Esiris excimer laser (Schwind). Patients were divided into 2 groups. One group had LASIK with an M2 microkeratome (Moria) (mechanical LASIK group) and the other, with a femtosecond laser (IntraLase FS, IntraLase Corp.) (femtosecond LASIK group). The relationship between the postsurgical corneal radius and the predicted sculpted radius as well as the mean value of the percentage change in the curvature radius were analyzed to obtain the effect on the refractive defect in each group. RESULTS: There were 44 eyes in the mechanical LASIK group and 41 eyes in the femtosecond LASIK group. A high correlation was found between the final corneal radius and the predicted sculpted radius in both groups (r(2) = 0.85). The mean percentage change in the curvature radius was -3.6% in the mechanical LASIK group and -1.6% in the femtosecond LASIK group (P<.001). The mean estimated refractive change was 1.2 diopters (D) and 0.8 D, respectively. CONCLUSIONS: The refractive change in corneal curvature, which related to the biomechanical response of the corneal surface after the flap cut and repositioning, was lower after femtosecond laser LASIK than after LASIK performed using a mechanical microkeratome. Estimations of refractive change induced by this response should be taken into account in surgery design.     

A comparative study for mesopic contrast sensitivity between photorefractive keratectomy and laser in situ keratomileusis.

BACKGROUND AND OBJECTIVE: To compare the effect on visual performance of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) with mesopic contrast sensitivity. PATIENTS AND METHODS: Postoperative visual performance for 40 eyes undergoing PRK and 40 eyes undergoing LASIK was compared with mesopic contrast sensitivity at 1, 3, and 6 months postoperatively. Eyes were divided into two groups (< -6.0 D and > -6.25 D). Mesopic contrast sensitivity was performed with the patient's best-corrected visual acuity of 20/20 or better under photopic conditions. RESULTS: A significant decrease in mesopic contrast sensitivity from preoperative baseline was obtained at all spatial frequencies for the PRK and LASIK groups (P < .05). There was no statistically significant difference at 1 or 3 months postoperatively in both groups (P > .05). At 6 months postoperatively, LASIK significantly decreased mesopic contrast sensitivity more than PRK in myopia with a refractive error of less than -6.0 D, especially at the middle and high spatial frequencies of 6, 9, and 12 cycles per degree (P < .05). However, no statistically significant differences in mesopic contrast sensitivity between PRK and LASIK were found in myopia with a refractive error of greater than -6.25 D (P > .05). CONCLUSIONS: In broad-beam excimer laser refractive surgery, PRK seemed to have a more significant effect on mesopic contrast sensitivity than LASIK for myopia with a refractive error of less than -6.0 D at 6 months postoperatively.     

角膜波前引导的LASIK治疗低中度近视角膜高阶像差的临床观察

目的:比较角膜波前像差引导下的准分子激光原位角膜磨镶术(laser in situkeratomileusi,LASIK)和常规的LASIK对低中度近视角膜高阶像差的影响。方法:采用前瞻性非随机对比研究,选取6mo内连续的低中度近视患者32例58眼实施常规LASIK(A组,其中低度近视24眼,中度近视34眼),34例52眼实施角膜波前引导下的个性化LASIK(B组,其中低度近视23眼,中度近视29眼)。所有手术均使用德国Schwind公司Esiris第九代准分子激光治疗仪和Carriazo Pendular钟摆式角膜板层刀,使用4.2.0版本的Optikon keratron Scout2000角膜地形图对两组患者在术前和术后3mo进行6mm瞳孔直径时角膜高阶像差检查。结果:两组病例角膜球差和均方根均高于术前。A组低度近视术后高阶像差增加量依次为均方根0.236μm、彗差0.146μm、球差0.139μm和三叶差0.054μm,中度近视高阶像差增加量依次为均方根0.367μm、球差0.284μm、彗差0.177μm和三叶差0.021μm。B组低度近视高阶像差增加量依次为球差0.127μm、均方根0.088μm、三叶差0.051μm、和彗差0.042μm,中度近视高阶像差增加量依次为均方根0.175μm、球差0.162μm、彗差0.027μm和三叶差0.024μm;两组病例术后3mo裸眼视力非常接近.同样条件下低中度近视角膜波前像差引导下的个性化LASIK切削的深度较常规LASIK深。结论:角膜波前像差引导下的低中度近视LASIK较常规LASIK角膜高阶像差影响少。