准分子激光原位角膜磨镶术与准分子激光角膜上皮瓣下磨镶术后角膜知觉恢复的研究

目的 比较准分子激光原位角膜磨镶术（LASIK）和准分子激光角膜上皮瓣下磨镶术（LASEK）后角膜知觉的恢复情况。方法 本研究观察在我院行LASIK或LASEK近视矫正的患者59例（59只眼）,包括低、中度近视行LASEK者20只眼,高度近视行LASEK者30只眼,以及低、中度近视行LASIK者9只眼。分别在术前、术后2周、1、3、6个月时测量角膜中央知觉,并和切削深度进行相关性检验。结果 LASIK和LASEK术后角膜知觉均下降,但LASIK术后下降更明显。在各观察时间点,LASEK术后的角膜知觉均好于LASIK术后2周、1个月和3个月时差异均有统计学意义（P〈0．01）,6个月时P=0．031。低、中度近视LASIK术后6个月时角膜知觉仍未恢复（P=0．023）;而LASEK术后3个月时角膜知觉已恢复（P〉0．05）。高度近视LASEK术后6个月时角膜知觉基本恢复（P〉0．05）。LASEK术后1、3及6个月的角膜知觉和切削深度有相关性（r=0．419,0．433,0．413;P〈0．05）,其余观察时间点两者无相关性。LASIK术后各时间点的角膜知觉和切削深度无相关性（P〉0．05）。结论 LASEK术后角膜知觉的恢复较LASIK术后快,LASEK术后角膜知觉的恢复和切削深度有关。     

准分子激光原位角膜磨镶术与角膜上皮下磨镶术对中高度近视高阶像差影响的对比研究

目的 比较准分子激光原位角膜磨镶术（LASIK）和准分子激光上皮下磨镶术（LASEK）对中高度近视眼高阶像差的影响。方法 选择中高度近视行准分子激光屈光手术的连续病例27例（41眼）,其中LASIK14例（23眼）、LASEK13例（18眼）。使用Zeiss-WASCA客观像差仪在术前和术后6月测量患眼暗室自然瞳孔下的波前像差。结果 术后6月两组总高阶像差均方根（RMSh）以及3～5阶高阶像差均方根（RMS3～5）均明显高于术前,以RMS4最明显。LASIK组术后RMSh的增幅高于LASEIK组（P=0.042）。LASIK组术后Y轴彗差（Z8）与球差（Z12）明显增高（均P〈0.01）。LASEK组术后Z12明显增高（P〈0.01）。LASIK组术后Z8大于LASEK组（P=0.021）。结论 对于中高度近视矫正,LASEK对高阶像差的影响比LASIK小。     

LASIK与LASEK术后角膜前后表面像差的变化

目的 探讨准分子激光原位角膜磨镶术(LASIK)与准分子激光上皮下角膜切削术(LASEK)手术前后角膜前、后表面球差(C球)、彗差(C慧)、三叶草像差(C三)和总高阶像差(C高)的变化.方法 前瞻性病例对照研究.应用Oculyzer眼前节分析系统采集并计算LASIK组17例(34眼)、LASEK组17例(34眼)患者的角膜前后表面的各像差.对检查结果进行方差分析、独立样本t检验和Pearson相关分析.结果 LASIK组角膜前表面C球、C高在术后1个月和3个月时均较术前有明显增加,术后1个月和3个月时比较差异无统计学意义;LASEK组角膜前表面C球、C慧和C高在术后1个月和3个月时均较术前有明显增加,术后1个月和3个月时比较差异无统计学意义;术后1个月时LASIK组的角膜前表面C球和C高高于LASEK组,术后3个月仍呈现同样趋势,而角膜前表面C慧始终低于LASEK组,C三差异无统计学意义;术后LASIK组角膜前表面C球和C高的增高值(△C球、△C高)高于LASEK组,而C慧和C三的变化在两组之间差异无统计学意义;角膜前表面△C球和△C高与矫正的等效球镜度呈现显著的正相关关系;两种术式间、同种术式手术前后角膜后表面各像差值差异无统计学意义.结论 LASIK和LASEK术后角膜前表面的C球、C慧和C高会增大,且在术后3个月时尚无明显恢复;到术后3个月,角膜前表面△C球和△C高在LASIK组始终高于LASEK组,而这种变化与所矫正等效球镜度呈正相关;两种术式对角膜后表面的各像差均无影响.     

微型角膜刀法与乙醇浸润法准分子激光角膜上皮瓣下磨镶术对角膜基质细胞影响的实验研究

目的探讨微型角膜刀法准分子激光角膜上皮瓣下磨镶术（Epi-LASIK）与乙醇浸润法准分子激光角膜上皮瓣下磨镶术（LASEK）对角膜基质细胞的影响研究。方法50只新西兰大白兔随机编号,其中48只（96只眼）随机一只眼行Epi-LASIK,另一只眼行LASEK,余2只（4只眼）未进行手术,作为对照组。采用核苷酸末端转移酶介导的dUTP缺口标记（TUNEL）法观察角膜基质细胞的凋亡情况、Ki-67和d平滑肌肌动蛋白（α-SMA）的免疫组化和免疫印迹法测定角膜组织d-SMA蛋白来观察角膜基质细胞的增殖与向肌成纤维母细胞转化情况,进行计数与半定量分析,对haze形成影响进行分析。结果Epi-LASIK与LASEK术后角膜基质中均有较多的TUNEL阳性细胞出现,在术后24h达最高峰,LASEK术后1周内细胞凋亡情况较Epi-LASIK明显（t=3．63、7．80、4．34、2．95,均P〈0．01）。术后1周基质Ki-67阳性细胞表达增高,72h时达高峰,两组在1周内差异有统计学意义（t=3．81、5．85、5．09、5．59,均P〈0．01）。α-SMA阳性细胞在术后1周明显出现,3个月时仍有较高表达,在术后1个月时阳性细胞数达高峰,α-SMA蛋白表达量的情况与α-SMA阳性细胞数变化一致,均提示LASEK术后增高的情况较Epi-LASIK差异有统计学意义（t=2．97、7．19、6．73,均P〈0．01）。结论Epi-LASIK较LASEK有着更少的角膜基质细胞凋亡、更弱的增殖以及向肌成纤维母细胞的转化,提示Epi-LASIK较LASEK有着更轻的haze反应几率。     

Effectiveness of laser-assisted subepithelial keratectomy to treat residual refractive errors after laser in situ keratomileusis

PURPOSE: To evaluate the effectiveness of laser-assisted subepithelial keratectomy (LASEK) to treat residual refractive errors after laser in situ keratomileusis (LASIK). SETTINGS: Isik Eye Clinic, Ankara, Turkey. METHODS: This retrospective study included 24 eyes of 15 patients who had retreatment by LASEK for residual refractive errors after myopic LASIK. All patients had examinations that included slitlamp biomicroscopy, subjective and cycloplegic refractions, uncorrected visual acuity (UCVA), best corrected visual acuity, corneal topography, and pachymetry preoperatively and postoperatively. Postoperative examinations were performed at 1 week and 1, 3, and 6 months. RESULTS: The patient cohort comprised 9 men and 6 women. The median spherical equivalent (SE) of attempted correction for retreatment with LASEK was -1.25 diopters (D). The median follow-up after LASEK was 11.5 months (range 6 to 16 months). At the end of the follow-up, the median SE of the refractive error was -0.38 D. The median UCVA increased from 20/45 before LASEK to 20/25 at the last follow-up visit, which was statistically significant (P<.001). After LASEK, significant postoperative haze developed in 5 eyes. In all 5 eyes, the estimated ablation depth was more than 40 mum and the SE of attempted correction was -2.00 D or greater. CONCLUSIONS: Laser-assisted subepithelial keratectomy retreatment in eyes with myopic regression after LASIK resulted in a significant improvement in UCVA that was comparable to the improvement after flap lifting. An SE of attempted correction greater than -2.00 D was associated with a significant rate of haze.     

Laser-assisted subepithelial keratectomy retreatment after laser in situ keratomileusis

PURPOSE: To evaluate the efficacy and safety of laser-assisted subepithelial keratectomy (LASEK) retreatment after laser in situ keratomileusis (LASIK). SETTING: Mater Private Hospital, Dublin, Ireland. METHODS: In this retrospective study, 22 eyes of 20 patients had LASEK retreatment for residual refractive errors after LASIK. All patients who had the procedure between January 2004 and May 2007 were included in the study. The main outcome measures at the final follow-up visit were efficacy, predictability, safety, and stability. RESULTS: The mean spherical equivalent (SE) was -4.50 diopters (D)+/-2.88 (SD) (range -10.00 to +3.87 D) before LASIK and -1.23+/-0.95 D (range -2.50 to +2.00 D) after LASIK. The mean time between the initial LASIK procedure and LASEK enhancement was 56.2+/-24.3 months (range 6 to 84 months). The mean follow-up after retreatment was 6.68+/-6.47 months (range 3 to 24 months). At the final follow-up visit, 19 eyes (86.4%) had an uncorrected visual acuity of 20/30 or better and 17 eyes (77.3%) were within +/-1.00 D of the target refraction. No patient lost more than 1 line of best corrected visual acuity or developed corneal haze greater than grade 1. CONCLUSION: Results indicate that LASEK retreatment after LASIK is a safe and effective alternative when LASIK retreatment is deemed unsafe because there is not sufficient residual corneal stromal bed or when retreatment is required many years after LASIK and relifting the original flap is expected to be problematic.     

Effect of laser in situ keratomileusis and laser-assisted subepithelial keratectomy on retinal nerve fiber layer thickness

PURPOSE: To evaluate and compare the influence of laser in situ keratomileusis (LASIK) and laser-assisted subepithelial keratectomy (LASEK) on the peripapillary retinal nerve fiber layer (RNFL) thickness. SETTING: Observational case series. METHODS: Twenty nonglaucomatous patients with mild to moderate myopia were included. One eye in each patient was randomly selected to have LASIK (Group 1, n = 20), and LASEK was performed in the fellow eye (Group 2, n = 20). The RNFL thickness measurements were performed using optical coherence tomography (OCT) preoperatively and 1 day and 1 month postoperatively. The RNFL thickness parameters were compared using repeated-measures 1-way analysis of variance (ANOVA) followed by multiple comparison tests in both groups. The main outcome parameter was RNFL thickness as determined by OCT before and after LASIK and LASEK. RESULTS: The mean age of the patients was 21 years +/- 3.2 (SD). The mean preoperative spherical equivalent was -4.23 +/- 1.71 diopters (D) in Group 1 and -4.16 +/- 1.68 D in Group 2. The mean ablation depth was 73.35 +/- 27.85 microm and 66.35 +/- 23.64 microm in groups 1 and 2, respectively. In Group 1, the mean average RNFL thickness, inferior average, superior average, temporal average, and nasal average were 98.2 +/- 5.6 microm, 128.6 +/- 11.9 microm, 120.38 +/- 10.2 microm, 65. 8+/- 7.1 microm, and 80.5 +/- 18.8 microm, respectively. None of the RNFL thickness parameters or RNFL ratios were found to have a significant change after surgery. In Group 2, the average RNFL thickness, inferior average, superior average, temporal average, and nasal average were 98.47 +/- 5.9 microm, 128.38 +/- 14.3 microm, 125.1 +/- 8.8 microm, 66.4 +/- 8.2 microm, 73.6 +/- 15.8 microm, respectively. No significant change was observed in any of the parameters following surgery. No significant alterations were noted in the RNFL parameters following LASIK or LASEK. CONCLUSIONS: Laser in situ keratomileusis and LASEK did not significantly affect the RNFL thickness parameters postoperatively.     

Comparison of wavefront aberration changes in the anterior corneal surface after laser-assisted subepithelial keratectomy and laser in situ keratomileusis: preliminary study

PURPOSE: To compare changes in anterior corneal wavefront aberrations after myopic laser-assisted subepithelial keratectomy (LASEK) and laser in situ keratomileusis (LASIK). SETTING: Institute of Ophthalmology, Catholic University, Rome, Italy. METHODS: This prospective study included 36 eyes of 25 myopic patients: 18 eyes of 12 patients had LASEK and 18 eyes of 13 patients, LASIK. The topography data (CSO EyeMap, version 6.2) were used to calculate corneal aberrations with 3.0 mm and 7.0 mm pupils before and 3 months after surgery. RESULTS: Total corneal aberrations increased similarly after LASEK and LASIK with the 7.0 mm pupil but did not change with the 3.0 mm pupil. Coma-like and spherical-like aberrations changed similarly after both procedures, but spherical-like aberrations increased after LASEK with the 3.0 mm pupil (P<.05, independent t test). With the 7.0 mm pupil, the amount of achieved correction was positively correlated with changes in total corneal aberrations after LASIK (P =.007) and with spherical-like aberrations after LASEK (P =.03) and LASIK (P<.003). Although there was no significant difference between LASEK and LASIK (P>.05, independent t test), in individual eyes with an achieved correction less than 7.50 diopters (D), spherical-like aberrations increased more after LASEK than after LASIK. CONCLUSIONS: In this preliminary study, myopic LASEK and LASIK changed total and higher-order corneal aberrations. In both procedures, changes in spherical-like aberrations were dependent on the achieved correction. However, in individual eyes, spherical-like aberrations increased more after LASEK than after LASIK for low-moderate achieved correction, suggesting that these procedures may induce the same optical changes in the anterior corneal surface in different ways.     

Comparison of ocular higher-order aberrations and visual performance between photorefractive keratectomy and laser in situ keratomileusis for myopia

The purpose was to compare the ocular higher-order aberrations and the visual performance between photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK). Ocular aberrations and visual performance were measured after PRK in 26 eyes, after LASIK in 39 eyes, and in 29 normal myopic control eyes. Ocular aberrations were measured with a Hartmann-Shack aberrometer. Visual performance was evaluated with grating contrast sensitivity, high and low contrast visual acuity, and letter contrast sensitivity under full correction with spectacles. The results were that the root mean square (RMS) values of ocular higher-order aberrations after PRK or LASIK were significantly greater than that of normal controls for both 4-mm and 6-mm zones (PRK; 0.22 +/- 0.09 and 0.85 +/- 0.24 microm, LASIK; 0.20 +/- 0.06 and 0.82 +/- 0.24 microm, normal; 0.10 +/- 0.03 and 0.33 +/- 0.11 microm. P < 0.05 between PRK and normal, LASIK and normal, One Way ANOVA on Ranks). There were no significant differences between PRK and LASIK. The ocular higher-order aberrations increased in proportion with the attempted refractive correction by PRK and LASIK. The ocular higher-order aberrations correlated better with grating contrast sensitivity, low contrast visual acuity, and letter contrast sensitivity than with high contrast visual acuity. There was no difference among normal, PRK and LASIK in all the visual function tests, except between normal and PRK, or between normal and LASIK with letter contrast sensitivity. In conclusion, there was no difference in both ocular higher-order aberrations and visual performance between PRK and LASIK. The result suggests that surgeons can choose refractive procedures according to the corneal conditions or daily activities of patients.     

Comparison of visual results between laser-assisted subepithelial keratectomy and epipolis laser in situ keratomileusis to correct myopia and myopic astigmatism

PURPOSE: To compare the visual results after laser-assisted subepithelial keratectomy (LASEK) and epipolis laser in situ keratomileusis (epi-LASIK) to correct myopia. DESIGN: Retrospective, interventional, nonrandomized comparative study. METHODS: Patients treated with LASEK to correct myopia < or = -9.00 diopters (D) were compared to age- and refraction-matched patients treated with epi-LASIK using the same excimer laser (Esiris; Schwind Eye Tech Solutions, Kleinostheim, Germany). The epithelial flap was replaced after the ablation in every case. The visual results after both procedures were compared at each postoperative visit (one day, one week, one and three months). RESULTS: Ninety-four consecutive eyes were included in the study (47 in each group), matched for age and refraction. The preoperative spherical manifest refraction was -3.98 +/- 2.40 D in the LASEK group and -3.95 +/- 2.40 D in the epi-LASIK group (P = .9) (range -0.50 to -9.00 D). The uncorrected visual acuity (UCVA) one day postoperatively was 0.7 +/- 0.2 and 0.5 +/- 0.2 (P < .001), and one week after surgery it was 0.8 +/- 0.2 and 0.7 +/- 0.2, respectively (P = .1). The difference was again statistically significant one month after surgery (0.94 +/- 0.1 after LASEK, 0.82 +/- 0.1 after epi-LASIK, P < .001), but not three months postoperatively (1.06 +/- 0.21 and 1.03 +/- 0.18, respectively, P = .1). UCVA was > or =1.0 in 78.7% of LASEK eyes and 65.9% of epi-LASIK eyes three months after surgery. At that moment, the safety indices were 0.99 +/- 0.1 after LASEK and 0.93 +/- 0.1 after epi-LASIK (P = .04). The efficacy indices were 0.97 +/- 0.1 and 0.89 +/- 0.1, respectively (P = .01). CONCLUSIONS: Our results suggest a faster visual rehabilitation and better safety and efficacy outcomes after LASEK compared to epi-LASIK with repositioning of the epithelial flap when correcting low to moderate myopia.     

标准及波前像差引导LASIK对高阶像差影响的对比研究

目的:比较常规准分子激光原位角膜磨镶术(标准LASIK)和波前像差引导的个体化准分子激光原位角膜磨镶术(波前像差引导LASIK)矫正中高度近视后高阶像差的变化情况。方法:选取2008-10/2009-05在我院行准分子激光手术者共60例120眼。按手术方式不同分为两组:波前组,接受波前像差引导的个体化准分子激光原位角膜磨镶术30例60眼;标准组,接受常规准分子激光原位角膜磨镶术30例60眼。所有患者于术前与术后6mo行波前像差(WaveScan WaveFrontTM System,AMOCo.,USA)检查,观察两组术前术后高阶像差的变化,并比较两组的差别。结果:所有患者无手术并发症,矫正视力≥1.0。波前组和标准组高阶像差均呈增加趋势,以彗差和球差增加为主。波前组HOAROM,Z7,Z8,Z12分别显著增加了73.2%,64.1%,128.9%和139.5%(P<0.05),标准组HOAROM,Z7,Z8,Z12分别显著增加了98.3%,149.1%,193.2%和107.8%(P<0.05)。波前组在总高阶像差(HOAROM)、30°三叶草(Z6)、垂直彗差(Z7)和水平彗差(Z8)高阶像差的改变显著优于标准组(P<0.05)。结论:术后6mo的随访结果表明,波前像差引导的LASIK可更好的控制术后高阶像差的增加,有助于患者获得更好的视觉质量。     

Comparison of optical quality parameters and ocular aberrations after wavefront-guided laser in-situ keratomileusis versus wavefront-guided laser epithelial keratomileusis for myopia

Background

To compare optical quality, ocular scattering, and higher-order aberrations (HOAs) after laser in-situ keratomileusis (LASIK) versus laser epithelial keratomileusis (LASEK).

Methods

A total of 47 eyes from 47 participants who had undergone LASIK (group I) or LASEK (group II) procedure at least 6 months prior were enrolled. Ocular aberrations and modulation transfer function (MTF) values measured using iTrace, a ray-tracing type aberrometer, were compared to MTF (modulation transfer function) cut-off values, Strehl ratio, and objective indices of scattering obtained using the Objective Quality Analysis System II (OQAS II).

Results

There was no significant correlation between the postoperative optical quality parameters and the HOAs between both groups. In group I, the MTF cut-off value was significantly correlated with cylinder refraction (p?=?0.037), and the objective scattering index (OSI) was positively correlated with spherical equivalent (p?=?0.023). In group II, there was a statistically significant correlation between the OSI and achieved refractive correction (p?=?0.001). Regression analysis showed that the OSI was the most significant predictor of MTF cut-off values after refractive surgery. Additionally, MTF values measured by OQAS were significantly lower than those measured by iTrace without correlation.

Conclusion

Optical quality after refractive surgery may be influenced by not only ocular aberrations but also by scattering. Even though the accuracies of the machines used in this study to measure optical quality have yet to be proven, this study showed limited correlation among the values measured using the two different machines after refractive surgery. Therefore, for more generalized evaluation of visual function after refractive surgery, more advanced optical devices still need to be developed.     

去瓣型Epi-LASIK与LASEK术后角膜上皮内紧密连接蛋白occludin的表达

背景 紧密连接作为角膜上皮屏障的重要构成部分,是角膜屈光手术后角膜上皮损伤修复中的关键因素,目前国内外有关这一方面的研究尚不多见. 目的 探讨和比较去瓣型微型角膜刀法准分子激光角膜上皮瓣下磨镶术(Epi-LASIK)与准分子激光上皮瓣下角膜磨镶术(LASEK)术后早期角膜上皮内紧密连接蛋白occludin的表达.方法 48只健康清洁级成年新西兰白兔按照随机数字表法随机分为2个组,每组24只.2个组均取右眼分别行去瓣型Epi-LASIK和LASEK手术,后者术中也不保留角膜上皮瓣.于术后1、2、3、5d用空气栓塞法处死实验兔并分离角膜组织,每个时间点获取6只兔眼角膜标本.另取2只正常兔为正常对照组.采用免疫荧光检查法观察各组兔眼角膜上皮内occludin蛋白的表达变化,用RT-PCR半定量检测兔眼中央区角膜内occludin mRNA表达的变化.结果 角膜免疫荧光检测结果表明,正常兔眼角膜上皮内可见occludin蛋白表达呈绿色荧光,荧光信号较强且排列有序.术后1～2d,LASEK组兔眼角膜上皮内绿色荧光信号表达强度低,数量少且排列紊乱,而去瓣型Epi-LASIK组角膜上皮内荧光信号强于LASEK组且排列整齐,术后3～5d,2个组荧光信号均增强,排列有序.RT-PCR检测表明,术后1、2、3d,LASEK组兔眼角膜上皮内occludin mRNA表达相对值分别为0.11±0.02、0.25±0.03、0.43 ±0.04,明显低于去瓣型Epi-LASIK组的0.20±0.04、0.44±0.04、0.76±0.04,差异均有统计学意义(t=6.476、12.898、17.315,P＜0.05);术后5d,2个组角膜上皮内occludin mRNA表达相对值差异无统计学意义(t=-0.733,P＞0.05).2个组随着术后时间的延长,occludinmRNA表达相对值均逐渐升高,总体差异有统计学意义(F时间=768.903,P=0.000). 结论 与LASEK比较,去瓣型Epi-LASIK对角膜上皮紧密连接的损害轻,术后角膜上皮紧密连接的修复也更加迅速,提示去瓣型Epi-LASIK有利于减少术后角膜刺激症状和并发症的发生.     

Ocular higher-order aberrations and contrast sensitivity after conventional laser in situ keratomileusis

PURPOSE: To investigate prospectively the relation between induced changes in higher-order aberrations of the eye and changes in contrast sensitivity by conventional laser in situ keratomileusis (LASIK) for myopia. METHODS: In 200 eyes of 110 consecutive patients (mean age, 32.7 +/- 8.4 years) undergoing LASIK, ocular aberrations and contrast sensitivity function were determined before and 1 month after surgery. The amount of myopic correction was 5.2 +/- 2.8 D (range, 1.0-13.0). Ocular higher-order aberrations were measured for a 4-mm pupil using the Hartmann-Shack wavefront analyzer (KR-9000PW; Topcon, Tokyo, Japan). The root mean square (RMS) of the third- and fourth-order Zernike coefficients was used to represent coma- and spherical-like aberrations, respectively. Total higher-order aberrations were calculated as the RMS of the third- and fourth-order coefficients. Contrast sensitivity and low-contrast visual acuity were measured. From the contrast sensitivity data, the area under the log contrast sensitivity function (AULCSF) was calculated. RESULTS: LASIK significantly improved logMAR best corrected visual acuity (Wilcoxon signed-rank test, P <0.001), but significantly reduced AULCSF (P <0.001) and low-contrast visual acuity (P=0.007). Total higher-order (P <0.001), coma-like (P <0.001), and spherical-like (P <0.001) aberrations were significantly increased after LASIK. The greater the amount of achieved myopia correction was, the more the changes in contrast sensitivity function and ocular higher-order aberrations were. The induced changes in AULCSF by LASIK showed significant correlations with changes in total higher-order (Pearson r=-0.221, P=0.003), coma-like (r=-0.205, P=0.006), and spherical-like (r=-0.171, P=0.022) aberrations. The changes in logMAR low-contrast visual acuity by surgery significantly correlated with changes in total higher-order (r=0.222, P=0.003), coma-like (r=0.201, P=0.007), and spherical-like (r=0.207, P=0.005) aberrations. CONCLUSIONS: Conventional LASIK significantly increases ocular higher-order aberrations, which compromise the postoperative contrast sensitivity function.