ORK-CAM引导的非球面切削不同近视组间屈光参数比较

目的:研究ORK-CAM引导的非球面切削个体化手术不同程度近视组间手术前后的角膜总体像差、球差、彗差和Q值的变化特点,并进行对比分析。方法:选取2010年在眼科激光中心行ORK-CAM引导的非球面切削个体化手术的250例500眼近视病例,其中低中度近视组有125例250眼,高度近视组有125例250眼。分别对两组病例手术前后的裸眼视力、等效球镜度、角膜总体像差RMS、球差、彗差和Q值的变化进行比较,随访6mo,所有数据采用SPSS 17.0进行统计分析,P<0.05有统计学差异。结果:两组术后裸眼视力分别为1.15±0.16和1.13±0.14,无统计学差异。两组术后残余等效球镜度均减少,但无统计学差异。术后角膜总体像差RMS、球差、彗差和Q值均增加,但高度近视组的增幅大于低中度近视组(P<0.05)。结论:ORK-CAM引导的非球面切削个性化手术对低中高度近视的治疗都是有效和安全的。但如要进一步减少高度近视术后角膜总体像差、球差、彗差和Q值的增加仍需深入探索。     

ORK-CAM角膜像差引导与传统切削模式近视LASIK手术比较研究

目的 探讨ORK-CAM角膜波阵面像差引导的近视LASIK手术的临床效果并与传统近视切削模式相比较.方法 回顾性分析接受近视LASIK手术的患者75例149只眼的临床资料.其中ORK-CAM角膜像差引导切削组4l例81只眼,常规切削组34例68只眼.统计患者术前和术后6个月的临床资料并进行手术前后以及两组间对比.主要观察指标包括裸眼视力、屈光度、角膜非球而系数、RMSh、RMS3-RMS7、球差、慧差以及三叶草像若值等.结果 两组术后角膜形态均由术前的长椭圆形变为扁椭圆形,ORK-CAM组角膜非球面系数改变较常规IASIK组小.两组术后角膜高阶像差均较术前显著增加.术后ORK-CAM组RMSh、RMS3、RMS4、球差以及三叶草像差值较常规IASIK组低,差异有统计学意义;术后ORK-CAM组6阶像差值较常规LASIK组高,二次球差是影响RMS6变化的主要因素.角膜Q值与球差值成正相关.结论 ORK-CAM角膜像差引导的个体化切削能够减小近视LASIK手术后角膜高阶像差的异常增加,术后角膜非球面性更接近于术前,有利于患者获得更好地术后视觉质量.     

LASIK后角膜高阶像差改变分析

目的 探讨近视LASIK术后角膜高阶像差的变化情况.方法 回顾性分析近视LASIK手术患者75例145只眼,比较患者术前术后角膜非球面系数(Q值)、总体高阶像差均方根值(RMSh)、3～7阶像差均方根值(RMS3-RMS7)、球差、慧差、三叶草像差等数值,用多元线性回归分析筛选引起术后角膜高阶像差改变的因素.结果 术前角膜高阶像差与年龄无相关关系;术后各观察值的大小主要受术前相应各数值的大小、预矫屈光度数、切削区大小等因素的影响,术前值越大、预矫屈光度越大以及切削区越小,术后角膜高阶像差值越大;术后Q值、RMSh以及球差的增加量主要受预矫屈光度数和切削区大小的影响;慧差以及三叶草像差的增加与切削区大小无关.使用较小切削区(5.25mm)时的单位屈光度矫正引起的高阶像差增加值以及角膜前表而非球面系数改变值高于使用较大切削区时,差异有统计学意义.结论 LASIK术后角膜高阶像差增大,预矫屈光度数高和切削区小是引起术后角膜高阶像差增加较大的主要原因.     

波前像差引导FS-LASIK矫正中高度近视患者术后1年眼前节变化

目的 探讨波前像差引导FS-LASIK矫正中高度近视患者术后1年对眼前节结构的影响。方法 收集2020年7月至2021年3月在徐州市第一人民医院就诊符合手术适应证且接受波前像差引导FS-LASIK患者共40例78眼的临床资料,分为中度近视组和高度近视组;分别于术前、术后1个月、术后1年行Pentacam AXL眼前节分析仪测量眼前节,包括角膜后表面Q值,全角膜像差,后表面高阶像差、球差、彗差,角膜后表面曲率、顶点高度及最薄点高度,前房深度(ACD)、前房容积(ACV)和前房角(ACA),并对比分析。结果 中度近视组患眼角膜后表面曲率和角膜后表面Q值术前与术后1个月、术后1年相比差异均有统计学意义(均为P<0.05),高度近视组患眼角膜后表面最薄点高度和角膜后表面Q值术前与术后1年相比差异均有统计学意义(均为P<0.05)。中度近视组患眼角膜后表面垂直彗差术前与术后1个月、术后1年相比差异均有统计学意义(均为P<0.05),高度近视组患眼全角膜像差、角膜后表面球差和垂直彗差术前与术后1个月、术后1年相比差异均有统计学意义(均为P<0.05)。中度近视组及高度近视组...     

非球面切削LASEK和LASIK治疗不同厚度角膜的高度近视

目的 探讨角膜波前像差联合Q值优化的非球面切削准分子激光上皮下角膜切削术(LASEK)与角膜波前像差联合Q值优化的非球面切削准分子激光原位角膜磨镶术(LASIK),分别治疗角膜薄(<500μm)和角膜厚(>500μm)的高度近视的临床疗效比较.方法 选取角膜厚度薄的高度近视患者行LASEK治疗25例(42只眼),角膜厚的高度近视患者38例(65只眼),比较术前视力、年龄、角膜厚度、切削厚度、剩余角膜厚度、等效球镜度、球差、慧差、总阶像差,术后2周,4周,3月,6月的视力,比较术后6月两组视力、等效球镜度、球差、慧差、总阶像差、HAZE等级.结果 两种手术方式术后6月内的视力,术后6月的等效球镜度、球差、慧差、总阶像差均无统计学意义,治疗高度近视具有相同均具有很高的安全性、有效性及可预测性且两组具有相同的临床疗效.结论 非球面切削的LASEK治疗角膜薄的高度近视与非球面切削的LASIK治疗角膜厚的高度近视具有相同的临床疗效.     

江西近视手术人群角膜前表面非球性参数调查分析

目的 调查江西近视激光手术人群角膜前表面非球性参数(Q值)的分布特征,并分析Q值与其他参数如屈光度、角膜平均曲率、角膜散光、像差、年龄等凶素的关系.方法 应用Orhscan- Ⅱ角膜 地形图仪(Bausch & Lomb)K＆Q计算软件获得411例近视患者822只眼角膜6mm分析区域的Q值和K值,使用Zywave波前像差仪获取完全的像差分布图像.按性别不同分为男性组(188例376只眼)和女性组(223例446只眼).按照近视程度不同分为轻、中、高度三组.按年龄分为Ⅰ组(17～25岁)、Ⅱ组(26～34岁)、Ⅲ组(35～44岁)三组.并对性别间、不同程度近视、不同年龄组间Q值的差别,总体Q值的分布及与其他参数如屈光度、角膜平均曲率、角膜散光、像差、年龄等因素的相关性进行统计学分析.结果 411例822只近视眼角膜Q值呈正态分布,总体Q值平均为-0.148±0.120,男性为-0.130±0.128,女性为-0.163±0.110,男女间差异有统计学意义(t=4.069,P<0.01).不同程度近视组间角膜Q值差异无统计学意义(F=1.434,r=0.239,P>0.05),Q值与近视屈光不正度数间无明显相关;不同年龄组间Q值的差异有统计学意义(F=4.567,P<0.05),26～ 34岁和35～44岁组间角膜Q值差异有统计学意义(P<0.01);Q值与平均角膜曲率、角膜散光、高阶像差(RMSh)和水平彗差(C8)间均有统计学的相关性,尤其与球差(C12)间存在显著负相关,但与其他参数如总体像差(RMSg)、垂直彗差(C7)、角膜直径、角膜厚度、眼压、年龄之间无明显统计学相关性.结论 适宜激光手术的江西近视人群Q值呈正态分布,大部分人群的角膜曲率由中央到周边逐渐变平.角膜Q值与近视程度无关,个体间变异较大.Q值与平均角膜曲率、角膜散光、高阶像差(RMSh)和水平彗差(C8)相关,Q值和球差之间存在密切相关.性别间角膜Q值有统计学差异性,不同年龄组间的角膜Q值有统计学差异性.     

Q值引导的机械板层刀与飞秒激光制瓣的SBK术后角膜像差比较

目的比较Q值引导的机械刀制瓣前弹力层下角膜磨镶术（OUP-SBK）和飞秒激光制瓣SBK（Femto-SBK）2种手术方式对术眼角膜像差的影响。方法回顾性病例对照研究。138例患者（276眼）根据制瓣方式不同分为2组：OUP-SBK组77例,其中按术前等效球镜度（SE）分为低度近视组17例（SE≤-3.00 D）,中度近视组29例（-3.00 D＜SE＜-6.00 D）,高度近视组31例（SE≥-6.00 D）;Femto-SBK组61例,其中低度近视组13例,中度近视组24例,高度近视组24例。均采用Q值引导的准分子切削模式手术,分别于术前及术后1、3、6个月测量术眼角膜的总高阶像差、球差、水平彗差、垂直彗差、水平三叶草和斜向三叶草数据,采用方差分析和独立样本t检验进行统计分析。结果术后低度近视组角膜总高阶像差、球差、垂直彗差高于术前（F=32.4、14.6、4.6,P<0.01）;中度近视组角膜总高阶像差、球差、水平彗差、垂直彗差、水平三叶草术后高于术前（F=40.9、22.5、34.0、2.7、24.4,P<0.05）;高度近视组角膜总高阶像差、球差、水平彗差、垂直彗差OUP-SBK组明显高于Femto-SBK组（F=15.4、3.9、10.4、4.8,P<0.05）。结论对于高度近视患者,飞秒激光制瓣较角膜刀制瓣产生的像差少,能给患者提供更优质的视觉质量。     

非球面切削准分子激光角膜屈光手术的早期临床观察膊

目的 前瞻性研究非球面切削引导准分子激光角膜屈光手术的临床疗效.方法 将球镜-6.00D以下,柱镜0.00～2.00D的近视患者随机分成2组,Q调整组32例64眼行非球面切削引导准分子激光角膜屈光手术,对照组32例64眼行传统准分子激光原位角膜磨镶术(LASIK).观察术后裸眼视力,残余屈光度,高阶像差中的慧差、球差、总高阶像差均方根增加值和满意度等指标.结果 术后裸眼视力和残余屈光度两组比较差异无统计学意义,但Q调整组高阶像差的增加较对照组小,差异有统计学意义(P＜0.05).术后Q调整组患者的满意度情况比较,两组差异有统计学意义(P＜0.05).结论 非球面切削引导准分子激光角膜屈光手术可以减少术后角膜波面像差的增加,尤其是减少球差增加,明显改善视觉质量.     

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。     

不同屈光手术方式术后角膜高阶像差的相关研究

目的：探讨飞秒激光制作角膜瓣的准分子激光原位角膜磨镶术(laser in situ keratomileusis,LASIK)、准分子激光上皮下角膜磨镶术(laser epithelial keratomileusis,LASEK)和前弹力层下角膜磨镶术(sub-Bowman keratomileusis,SBK)三种手术方式术后人眼角膜高阶像差(包括彗差、球差及总高阶像差均方根)的变化。方法：近视患者82 例164 眼,其中行飞秒激光制瓣(FSLASIK)手术者31 例62 眼,B 组行SBK 者31 例62 眼,C 组行LASEK 者20 例40 眼,分别记录患者术前;术后1, 15d;1,3mo 彗差(C7,C8)、球差(C12)及高阶相差均方根(RMSh),并进行统计学分析。结果：(1)视力：术后各时段三组患者比较,差异无统计学意义(P>0. 05)。(2)角膜像差：三种手术方式对患者角膜像差均有显著影响,三组患者角膜彗差(C7,C8)、角膜球差(C12)、高阶相差均方根(RMSh)均于术后1d 开始显著增加(P<0. 05)。术后3mo,患者的C7,C8,C12 和RMSh 均未恢复至术前水平。但FS-LASIK 组患者增幅比其它两组小,差异有统计学意义(P<0. 05)。结论：与SBK 和LASEK 相比,飞秒做瓣LASIK 在术后早期拥有较好的裸眼视力,且术后角膜高阶像差的增幅相对较小。     

Q值调整非球面切削与标准化LASIK术后视觉质量临床分析

目的:通过对Q值调整非球面切削与标准化LASIK术后视觉质量的观察来分析Q值引导个性化切削技术的临床效果。方法:对2008-01/05等效球镜低于-12.00D的46例88眼进行非球面切削或标准化LASIK术后进行随访,按术前屈光度数将其分为A组(<-6.00D)和B组(-6.00～-12.00D)两组,对比各组非球面切削与标准化LASIK术后1mo裸眼视力、Q值、夜间眩光、夜间视物质量及满意率(后3者采取问卷调查)。结果:A、B组内非球面切削与标准化LASIK术后裸眼视力差异无统计学意义(t=1.18,P>0.05;t=0.62,P>0.05);A、B组内非球面切削与标准化LASIK术后Q值差异无统计学意义(t=-0.93,P>0.05;t=-0.372,P>0.05);A组内非球面切削与标准化LASIK术后眩光、夜间视物质量差异无统计学意义(眩光:χ2=2.397,P>0.05;夜间视物质量:χ2=1.263,P>0.05);B组内非球面切削与标准化LASIK术后眩光、夜间视物质量差异有统计学意义(眩光:χ2=10.85,P<0.01;夜间视物质量:χ2=10.85,P<0.01);术后效果满意率达到98.8%。结论:非球面切削能明显改善-6.00D以上的术后主观视觉质量。     

波前像差联合Q值优化的非球面切削治疗中低度近视的临床研究

目的:探讨波前像差引导联合Q值优化的非球面切削的准分子激光原位角膜磨镶术(laser in situkeratomileusis,LASIK)治疗中低度近视眼的临床疗效。方法:随机选取欲行LASIK治疗的符合条件的中低度近视患者158例进行前瞻性研究,分别对40眼使用波前像差联合非球面切削程序(A组),38眼使用Q值优化的非球面切削程序(B组),39眼使用波前像差程序(C组),41眼使用标准切削进行LASIK手术(D组),比较术前和术后1,3,6mo的波前像差值、裸眼视力、最佳矫正视力和验光值。结果:158例研究对象中所有患者手术均成功,在术后6mo随访期间无1例患者发生严重的并发症,4组间比较手术的精确性、安全性、有效性无统计学差异(P>0.05);术后6moA组总高阶像差均方根值和球差均方根值较其它3组小。结论:与标准的LASIK、单独使用波前像差或Q值优化的非球面切削技术相比波前像差引导联合Q值优化的非球面切削的LASIK手术更能有效地减少术后高阶像差的增加、改善术后视觉质量。     

Q值引导与波前引导的LASIK治疗近视的初步研究

目的:观察Q值引导与波前引导的LASIK治疗近视的疗效。方法:接受非球面切削与波前引导的LASIK治疗26例患者(52眼),每名患者的1眼使用Q值引导的切削,另1眼使用波前引导的个性化切削进行LASIK手术,分析2组的治疗效果。结果:术后3mo,2组手术眼视力矫正均满意,其间屈光度无差别(P>0.05);Q值引导组与波前引导组比较其术后角膜更倾向于长椭球形,Q值(0.24±0.32)低于波前引导组Q值(0.53±0.41)(P<0.01),当瞳孔直径为6mm时,两组术后高阶像差RMS均有增加,Q值引导组术后球差增加的幅度小于波前引导组,而彗差增加的幅度大于波前引导组。术后眩光发生率两组无显著性差异(P>0.05)。结论:使用Q值引导与波前引导的LASIK治疗近视及近视散光均是安全有效的,但仍存在不足,需要进一步改进、优化或整合。     

Photorefractive keratectomy with aspheric profile of ablation versus conventional photorefractive keratectomy for myopia correction: six-month controlled clinical trial

PURPOSE: To analyze ocular wavefront error and corneal asphericity (Q) in patients treated with aspheric profile photorefractive keratectomy (PRK) compared with patients having conventional PRK to correct myopia and myopic astigmatism and to evaluate the effect of postoperative corneal shape on visual performance. SETTING: Eye Clinic, University G. d'Annunzio, Chieti-Pescara, Italy. METHODS: Fifty eyes were treated with aspheric profile PRK using the MEL 80 flying-spot excimer laser, and 24 eyes were treated with standard PRK using the MEL 70 flying-spot excimer laser. RESULTS: Postoperative wavefront error increased in both groups. Six months after surgery, there was a smaller increase in root mean square (RMS) of total higher-order aberrations and spherical aberration (59% and 106%, respectively) in the aspheric profile PRK group than in the conventional PRK group (94% and 136%, respectively) (P<.01).The aspheric profile PRK group showed more prolate corneal asphericities (mean Q of 0.15 +/- 0.26) than the conventional group (mean Q of 0.45 +/- 0.26) (P<.001), with increasing oblateness for higher attempted corrections. A higher percentage of patients with better low-contrast uncorrected visual acuity and best corrected visual acuity was observed in the aspheric PRK group than in the conventional PRK group (P<.05). CONCLUSIONS: Aspheric profile and conventional PRK were safe and efficient for the correction of myopia and myopic astigmatism. Moreover, aspheric profile PRK induced a smaller increment of total wavefront error, was related to a smaller increase in spherical aberration, and better maintained the physiology of the corneal surface than conventional treatment.     

Corneal higher-order aberrations after customized aspheric ablation and conventional ablation for myopic correction

PURPOSE: To investigate and compare the corneal wavefront aberrations and corneal asphericity after customized aspheric and conventional myopic ablation. METHODS: Fifty-eight myopic patients from two laser centers were enrolled in this study. The patients were treated with laser in situ keratomileusis (LASIK) randomly with customized aspheric algorithm (32 patients, group A) and conventional algorithm (26 patients, group B). There was no significant difference in preoperative mean equivalent sphere (p = 0.954). The manifest refraction, corneal asphericity, and corneal wavefront data were taken into account to generate the customized aspheric ablation profile. Corneal wavefront aberrations, and corneal asphericity were analyzed and compared before and 6 months after the treatment. RESULTS: Preoperatively, no significant difference was found in corneal asphericity and higher-order aberrations (HOAs) between two groups (p = 0.833 and p = 0.459, respectively). Root mean square (RMS) value of corneal HOAs, spherical aberration, and corneal asphericity increased postoperatively in both groups (p < 0.05), but the smaller increase was shown in group A (p < 0.05). The Zernike third-order aberration increased by 10% (p = 0.088) but without significance in group A compared with significant increase by 27% (p < 0.01) in group B. CONCLUSIONS: The customized aspheric ablation induced smaller increase in corneal higher-order aberrations and corneal asphericity. It provides a good option for the customized myopic correction.     

Topographic- and wavefront-guided customized ablations with the NIDEK-EC5000CXII in LASIK for myopia

PURPOSE: To assess refractive outcomes, changes in the total higher order root mean square (RMS) aberration, and changes in higher order wavefront aberrations after LASIK for myopia and myopic astigmatism with the NIDEK Advanced Vision Excimer Laser platform (NAVEX) using either an aspheric or topography-based or whole eye wavefront ablation algorithm. METHODS: This was a retrospective study of 1459 eyes that underwent LASIK for myopia and myopic astigmatism. The mean preoperative spherical equivalent refraction was -4.68 diopters (D) (range: -0.50 to -9.63 D) with astigmatism up to -4.50 D. Treatments were classified into three categories depending on the type of ablation algorithm used--optimized aspheric transition zone (OATz) denoted eyes that underwent aspheric treatment zones; customized aspheric treatment zone (CATz) denoted eyes that underwent customized ablations based on corneal topography; and OPDCAT denoted eyes that underwent customized ablation based on the whole eye wavefront profile. Follow-up data are reported at 3 months (69%) and 12 months (17%) postoperatively. RESULTS: Three months after LASIK, the predictability (10.5 D from target refraction) was 80% for OATz, 91% for CATz, and 76% for OPDCAT. Of all eyes, 96% were within +/- 1.0 D of intended refraction 3 months postoperatively and 100% after 12 months (87% +/- 0.5 D). In the aspheric and custom groups, a notable improvement of uncorrected visual acuity was noted between 3 and 12 months after LASIK. No eye lost >1 line of best spectacle-corrected visual acuity. Mean higher order RMS increased in all groups. CONCLUSIONS: The data support that the treatment of myopia and myopic astigmatism is safe and effective with NAVEX. Customized ablation based on corneal topography rather than on total wavefront error was more predictable.     

LASIK非球面切削治疗近视眼术后3年角膜 Q 值及曲率变化

目的 比较准分子激光原位角膜磨镶术（LASIK）非球面切削及普通切削术后3年的角膜 Q 值及曲率变化。设计 回顾性比较性病例系列。研究对象 哈尔滨242医院行准分子激光近视治疗的患者155例（295眼）。方法 患者分非球面切削和普通切削两组,每组预留基质分为＞350 μm（A组）、300~350 μm（B组）及280~299 μm（C组）三组。不同术式两组患者术前年龄、等效球镜度数、中央角膜厚度无统计学差异。利用Orbscan II 检测术后1周,1、6个月,1、 3年角膜Q值及前表面曲率。主要指标 角膜Q值及前表面曲率。结果 手术后3年时,非球面切削者三组角膜Q值分别是A组0.27±0.21、B组0.33±0.31、C组0.93±0.19;角膜前表面曲率分别是（39.6±1.17）D、（39.9±0.83）D、（37.9±1.51）D。普通切削者三组的角膜Q值分别是A组0.35±0.24、B组0.71±0.35、C组1.03±0.36;角膜前表面曲率分别是（40.2±0.98）D、（39.6±0.33）D、（37.3±1.83）D,差异无统计学意义。结论 经过3年的观察显示,与LASIK普通切削模式相比,非球面切削在预留基质300~350 μm范围内能保持更好的角膜非球面形态。两组术式在预留基质280 μm以上时均是安全的。（眼科, 2014, 23： 301-304）     

Total and corneal optical aberrations induced by laser in situ keratomileusis for hyperopia

PURPOSE: To evaluate changes induced by standard laser in situ keratomileusis (LASIK) for hyperopia on total and corneal optical quality. METHODS: Total and corneal aberrations were measured before and after standard hyperopic LASIK in 13 eyes (preoperative spherical equivalent refractive error +3.17 +/- 1.10 D). The Chiron Technolas 217C laser with PlanoScan was used. Total aberrations (measured using laser ray tracing) and corneal aberrations (estimated from a videokeratoscope) were described using Zernike terms. Root-mean-square wavefront error for both total and corneal aberrations, and through-focus Strehl ratio for the point spread function of the whole eye were used to assess optical changes induced by surgery. RESULTS: Third and higher order aberrations increased significantly after hyperopic LASIK (by a factor of 2.20 for total and 1.78 for corneal aberrations, for a 6.5-mm pupil). Spherical aberration changed to negative values (corneal average decreased by -0.85 +/- 0.48 microm and total average by -0.70 +/- 0.30 microm). Best Strehl ratio for the whole eye decreased by a factor of 1.84. Hyperopic LASIK induced larger changes than myopic LASIK, compared to an equivalent group of myopic eyes from a previous study. Induced corneal spherical aberration was six times larger after hyperopic LASIK, for a similar range of correction, and of opposite sign. As with myopic LASIK, changes in internal spherical aberration are of opposite sign to those induced on the corneal anterior surface. CONCLUSIONS: Hyperopic LASIK induced significant amounts of aberrations. The largest increase occurred in spherical aberration, which showed a shift (toward negative values) of opposite sign; increase was greater than for myopic LASIK.     

Corneal wavefront-guided ablation with the Schwind ESIRIS laser for myopia

PURPOSE: To evaluate the outcome of corneal wavefront-guided LASIK for the treatment of myopia and myopic astigmatism. METHODS: This study included 56 myopic virgin eyes of 28 patients with a mean spherical equivalent refraction of -4.40 +/- 1.83 diopters (D) (range: -1.25 to -9.75 D) and astigmatism < 2.50 D. The corneal wavefront aberrations were analyzed using a corneal topography system. The preoperative corneal wavefront aberration data obtained from the above analyses combined with manifest refraction were used to generate a customized ablation profile. The safety, efficacy, and predictability of the correction, contrast sensitivity, and corneal higher order wavefront aberrations were evaluated. RESULTS: At 1-year follow-up, the mean residual spherical equivalent refractive error was -0.15 +/- 0.3 D (range: 0 to -1.25 D) and mean cylinder was -0.54 +/- 0.34 D (range: 0 to -1.50 D). Ninety-five percent of eyes were in the residual refractive error range of +/- 0.50 D and uncorrected visual acuity improved by 1.00 D or better in 94% of eyes. The safety index and efficacy index were 1.13 and 0.92, respectively. After treatment, corneal higher order wavefront aberrations with a 6-mm pupil diameter increased significantly (paired sample t test, P < .01), and contrast sensitivity with glare had small reductions at high spatial frequencies. Changes in spherical-like aberration (R = 0.708, P < .001) and higher order wavefront aberration (R = 0.449, P = .001), except for coma-like aberration (P = .238), were positively correlated with the amount of achieved correction. CONCLUSIONS: Evaluation of clinical results showed that corneal wavefront-guided LASIK for the correction of myopia and myopic astigmatism was safe and effective. There was an increase in all higher order aberrations postoperatively.