高度近视LASIK治疗中角膜瓣厚度的临床分析

目的分析高度近视LASIK治疗中,影响角膜瓣厚度的因素。方法40例(80只眼)屈光度为-7.00D~-9.00D的高度近视患者,运用MoriaM2板层刀制作角膜瓣,对角膜曲率不同、板层刀负压吸引力不同、M2刀片新旧不同进行分组,对术前、术后屈光度、视力及剩余角膜基质床厚度进行分析比较。结果Ⅰ组板层刀负压吸引力相同时角膜曲率不同,制作出的角膜厚度不同,两者有明显差异(P<0.05);Ⅱ组角膜曲率相同,板层刀负压吸引力不同,制作出的角膜瓣厚度不同,两者有明显差异(P<0.05);Ⅲ组板层刀片新旧不同,制作出角膜瓣的厚度不同,两者有明显差异(P<0.05);结论LASIK治疗高度近视时,对一个有经验的手术医生制作一个80~110μm的薄角膜瓣是合理的,能有效防止术后屈光回退和医源性圆锥角膜的发生。     

高度近视波前引导的LASIK后屈光回退角膜后表面形态变化

目的 观察高度近视波前引导的LASIK后屈光回退角膜后表面屈光力和后高度的变化及后表面高度最大值与角膜厚度最薄点的关系.方法 采用眼前节全景仪测量13眼高度近视渡前引导的LASIK后屈光回退患者的角膜后表面屈光力及后高度值,对这些参数进行统计学分析.结果 本次选取的46例(90眼)患者中术后12个月时发生屈光回退患者8例13眼.13眼术后12个月时角膜后表面屈光力及后高度值均比术前增加,差异均有统计学意义(均为P<0.05).角膜后表面顶点和最大高度的平均变化值分别为(3.21±1.62)μm和(2.30±1.11)μm,高于正常眼角膜后表面顶点和最大高度的平均变化值,但差异均无统计学意义(均为P>0.05).角膜后表面高度最大值与角膜厚度最薄点均不在同一位置.结论 重视高度近视渡前引导的LASIK后出现屈光回退时角膜后表面屈光力及后高度的变化,防止或及时发现术后圆锥角膜.     

高度近视LASIK术后远期屈光回退的相关因素分析

目的探讨高度近视准分子激光原位角膜磨镶术(laser in situ keratomileusis,LASIK)后远期屈光回退的各种可能影响因素。方法 96例(167眼)高度近视患者(术前SE-6.00~-10.00D),随访5~6a,对其中发生屈光回退的37眼和未发生屈光回退的130眼术前及术后5a的随访资料进行对比,检测LASIK术后不同时期的屈光度和屈光回退率;进行屈光回退单因素分析和多因素分析。结果 LASIK术后1d、1个月、3个月、6个月、1a、5a SE分别为(-0.08±0.31)D、(-0.09±0.32)D、(-0.15±0.47)D、(-0.15±0.46)D、(-0.21±0.51)D、(-0.55±0.80)D,均小于术前(P=0.000);术后不同时期屈光回退率分别为0、1.20%、2.40%、3.59%、5.40%、22.16%;屈光回退单因素分析结果显示:产生5个对屈光回退有意义的变量:(1)术前SE(P=0.003);(2)术前CCT(P=0.018);(3)术前与术后5a CCT变化值(术前CCT-术后5a CCT)(P=0.009);(4)术前与术后5a角膜曲率变化值(术前角膜曲率-术后5a角膜曲率)(P=0.019);(5)术中角膜中心切削直径(P=0.001)。屈光回退多因素分析:产生4个对屈光回退有意义的变量:术前SE高、术前与术后5a角膜曲率变化值小、术前与术后5a CCT小、术中角膜中心切削直径小者术后易出现屈光回退。它们对屈光回退的影响作用(标准回归系数的绝对值大者易出现屈光回退)从大到小依次为:术前SE|-0.581|>术前与术后5a角膜曲率变化值|-0.370|>术前与术后5a CCT变化值|-0.302|>术中角膜中心切削直径|-0.231|。结论 LASIK可有效治疗-6.00~-10.00D的近视。术前SE高、术前与术后角膜曲率变化值小、术前与术后CCT变化值小、术中角膜中心切削直径小者术后易出现屈光回退。手术技术和激光治疗的不断改进,将有助于提高LASIK的预测性,避免屈光回退现象发生。     

术前眼压、角膜厚度和高度近视术后视力的关系

目的:探讨高度近视患者术前眼压、中央角膜厚度与术后视力下降的密切关系。方法:对行准分子激光原位角膜磨镶术(laserinsitukaratomileusis,LASIK))、上皮下角膜磨镶术(laserepithelialkaratomileusis,LASEK)术后视力下降、屈光回退的高度近视眼患者90例,根据术前角膜厚度(cornealthickness,CT)眼压(intraocularpressure,IOP)值进行分组,分析术前眼压、角膜厚度和高度近视术后视力的关系。结果:术前角膜较厚,眼压较低,即CT/IOP比值大,术后裸眼视力较好,回退率越小;反之,术前角膜薄,眼压高,即CT/IOP值较小时,术后裸眼视力不稳定,回退率高。结论:LASIK、LASEK治疗高度或超高度近视有较好的疗效。为了使手术更安全,病例的选择、适应证的掌握尤为重要。     

超高度近视LASIK术后的屈光回退

目的探讨准分子激光原位角膜磨镶术(laser in situ keratomileusis,LASIK)矫正超高度近视的准确性、预测性、稳定性及有效性.方法 LASIK矫正超高度近视-10.1～-26.0 D,平均(-13.9±3.4)D 124例193眼,按术前预矫等值球镜分别观察术后1年的屈光度,术前最佳矫正视力及术后裸眼视力.结果术后1年屈光回退率与性别、年龄、切削方式无关(P＞0.05),而是随着术前预矫度数的增加而增加.术前预矫屈光度越高,屈光回退程度越明显.术后平均裸眼视力达0.6以上.结论超高度近视LASIK术后准确性、预测性及稳定性均较差,但由于其具有有效性,我们可以积极地为患者实施此项手术.     

从LASIK手术治疗高度近视的远期效果评价其手术的安全性

目的从LASIK手术治疗高度近视远期效果观察其手术的预测性与安全性.方法将连续随防2～3年的高度近视患者按高度近视(＞-6.0D～≤-10.0D),超高度近视(≥-10.25D～≤-15.0D)及极高度近视(≥-15.25D～≤-27.0D)分为3组,观察其术后裸视及术后屈光状态等进行比较分析.结果666眼术后裸视全部优于术前,其中609眼(91.44%)达到术前最佳矫正视力(BCVA),其中有57眼(8.56%)出现欠矫与回退.高度近视组回退率为3.16%,超高度近视和极高度近视组其回退率分别为13.81%和14.82%.屈光状态在0～±0.5D有504眼(75.67%),38眼(5.71%)呈过矫状态(＞+1.0D)中仅5眼低于术前BCVA一行,3眼低于术前BCVA2～3行,角膜层间混浊2眼(0.3%),眼底黄斑出血6眼(0.9%).结论LASIK手术治疗高度近视远期效果稳定,但由于受角膜厚度的限制,极高度近视的回退率明显增加,故认为LASIK手术最适宜-15.0D以下的高度近视.     

薄角膜中低度近视患者LASIK术后4年疗效观察

目的观察准分子激光原位角膜磨镶术（LASIK）治疗中央角膜厚度小于500μm中低度近视的安全性和远期疗效。方法选取2003年1至12月于我院接受LASIK手术的薄角膜中低度近视患者72例（136只眼），术前中央角膜厚度463～498μm（484．95±6．65）μm，术前等效球镜度-6．00～-1．50D（-3．74±1．27）D。检查术后4年的视力、屈光状态、Irreg值、角膜后表面Diff值和中央角膜厚度，并与术前及术后早期数据进行统计学对比和分析。结果术后4年均未发生继发进行性角膜扩张或医源性圆锥角膜，最佳矫正视力均无下降，平均等效球镜度为（-0．15±0．53）D，其中122只眼（89．7％）在-0．50～＋0．50D之间，屈光回退≥1．00D者8只眼（5．9％）；术后各阶段视力、等效球镜度、3mIrreg、5mIrreg以及中央角膜厚度差异无显著性（P〉0．05）；术后早期Diff值较术前明显增长（P〈0．05），但3个月后出现递减趋势。结论LASIK手术治疗薄角膜中低度近视具有良好的预测性和稳定的远期疗效。     

角膜厚度和眼压对高度近视准分子激光原位角膜磨镶术疗效的影响

目的探讨中央角膜厚度和眼压对高度近视准分子激光原位角膜磨镶术(excimer laser in-situ keratomileusis,LASIK)疗效的影响.方法采用LASIK对96例166眼高度近视患者进行治疗.根据术前中央角膜厚度(cornealthickness,CT)与术前眼压(intraocular     

降眼压药物治疗LASIK术后屈光回退3例

0引言准分子激光原位角膜磨镶术(Laser in situkeratomileu-sis,LASIK)与准分子激光屈光性角膜切削术(photorefrac-tive keratectomy,PRK)相比较,其术后稳定性大大提高,但是对于高度或超高度近视患者来说,屈光回退的发生率依然相当高[1,2]。一般认为,LASIK术后屈光回退的发病机制可能与组织增生和角膜前膨有关[3],但是到底是以组织增生为主,还是以角膜前膨为主,可能又存在较大的个体差异。对于屈光回退,目前除了在角膜厚度足够、屈光度稳定和排除圆锥角膜的情况下行增强术之外,没有其他治疗手段。我们对3例(6眼)LASIK术后屈光回退患者,运     

分区切削模式在LASIK治疗超高度近视的应用

目的评价对角膜相对较薄的超高度近视,应用分区切削模式进行LASIK治疗的临床效果。方法对95例(185眼)超高度近视,因选择6.0 mm直径的切削区,剩余角膜厚度小于250μm,而进行LASIK分区切削治疗,分区切削分为2～3区,切削光区4.7～6.0 mm。随访时间6～20月,观察手术前后的屈光状态、裸眼视力、矫正视力、角膜地形图及并发症的发生情况。结果术后1月视力达到最好并趋于稳定,所有患者的裸眼视力均较术前提高,术后3月183眼(98.92%)裸眼视力超过或等于术前最佳矫正视力。屈光回退47眼(25.41%),术后眩光51眼(27.57%),分析手术后角膜地形图,切削过度区光滑,无偏心切削。与标准手术相比可节省角膜厚度20%～25%,视力、屈光度变化与分区多少及近视度数有关。少数患者出现的眩光、夜视力下降等并发症,1个月后减轻或消失,角膜地形图均为正常负性形态。结论LASIK分区切削模式是对角膜相对较薄的超高度近视进行激光治疗有效安全的方法。可节省角膜组织,具有安全可靠,稳定性、可预测性强的临床效果。     

Posterior corneal ectasia following LASIK

PURPOSE: To evaluate the cases of posterior corneal ectasia following laser in situ keratomileusis. MATERIAL AND METHODS: Thirteen eyes of 7 patients, that were diagnosed to have posterior corneal ectasia (?0.060 mm) on Orbscan topographic system following LASIK, were identified. The parameters evaluated were uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), refraction, contrast sensitivity, glare, corneal topography, keratometry and pachymetry. The preoperative and postoperative data at day 1, 1 week, 1 month, 3 months, 6 months and 1 year were retrospectively analyzed. RESULTS: The mean UCVA of the patients before LASIK surgery was 0.032 +/- 0.04. It was 0.320 +/- 0.159 in follow-up of LASIK surgery after 1 year. The mean Pre-LASIK BCVA was 0.59 +/- 0.11. There was no change in mean BCVA at 1 year. The mean preoperative spherical equivalent was -14.25 +/- 2.91 D except in 2 hyperopic eyes in which the mean spherical equivalent preoperatively was +5.75 +/- 0.35 D. The mean postoperative spherical equivalent after 1 year of LASIK surgery in last follow-up (+/- enhancement) was - 3.45 +/- 2.08 in the myopic eyes and + 1.0 +/- 0.70 in the two hyperopic eyes. The mean preoperative posterior corneal elevation was 0.022 +/- 0.011 mm, which at the end of 1 week following LASIK was 0.067 +/- 0.009 and at 1 year/ last follow-up following LASIK, it was 0.068 +/- 0.006 mm. CONCLUSIONS: Higher amplitudes of refractive correction may lead to the occurrence of posterior corneal ectasia.     

Single Intacs segment for post-laser in situ keratomileusis keratectasia

PURPOSE: To describe the visual outcome of implantation of a single Intacs segment (Addition Technology Inc.) in eyes with keratectasia after myopic laser in situ keratomileusis (LASIK). SETTING: Private refractive surgery center, Jerusalem, Israel. METHODS: This retrospective, noncomparative, interventional, consecutive, small case series studied 5 eyes of 5 patients with post-LASIK keratectasia from 3 refractive laser centers treated by Intacs implantation. Before and 9 months after Intacs implantation, the uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, keratometry, videokeratography, inferior-superior asymmetry, and patient questionnaires about visual function were assessed. RESULTS: Intacs implantation was performed 17 to 32 months post LASIK with no intraoperative complications and no loss of visual acuity. After implantation, the UCVA improved 8, 4, 3, 0.5, and 5 lines and the BSCVA, 2, 2.5, 1, 0.5, and 2 lines. The mean manifest refraction spherical equivalent improved from -1.60 diopters (D) +/- 1.67 (SD) to -0.80 +/- 1.05 D. The mean manifest astigmatic correction decreased from -3.9 +/- 2.96 to -2.46 +/- 2.77 D. Corneal topography showed improved inferior steepening and less irregular astigmatism. The mean inferior-superior asymmetry improved from 7.88 +/- 4.59 to 2.46 +/- 2.77 D. Self-reported visual symptoms improved significantly in Cases 1, 2, and 5 and slightly in Cases 3 and 4. CONCLUSIONS: Implantation of a single Intacs segment inferiorly appeared to improve progressive myopia and regular and irregular astigmatism in eyes with corneal ectasia after LASIK. With further study, this technique may prove to be an effective, relatively noninvasive approach.     

Correction of severe ectasia after LASIK with intracorneal ring segments

PURPOSE: To report a case of severe bilateral ectasia after LASIK that was treated with implantation of small-diameter Keraring intrastromal corneal ring segments (Mediphacos Ltd). METHODS: A 31-year-old woman underwent LASIK in 2001 at a different institution. One year after LASIK, the patient complained of decreased vision in the left eye and underwent LASIK retreatment. Three months after retreatment, uncorrected visual acuity (UCVA) was counting fingers and best spectacle-corrected visual acuity (BSVCA) was 0.4 in the left eye; UCVA was 0.1 and BSCVA was 0.3 in the right eye. Corneal topography showed inferior steepening bilaterally, consistent with ectasia, and the patient was fitted with rigid gas permeable contact lenses. The patient presented to our clinic 4 years after bilateral LASIK with severe loss of BSCVA in both eyes. Examination confirmed the diagnosis of severe bilateral ectasia. The patient underwent implantation of small-diameter Keraring segments assisted by femtosecond laser in June 2005 (left eye) and March 2006 (right eye). RESULTS: Best spectacle-corrected visual acuity improved by four lines in both eyes. Postoperative keratometry showed a decrease of seven diopters in the right eye and nine diopters in the left eye. Postoperative refraction and keratometry have remained stable for 18 and 10 months in the left and right eyes, respectively. CONCLUSIONS: Implantation of intracorneal ring segments can be considered as a treatment option in patients with severe ectasia after LASIK.     

准分子激光原位角膜磨镶术后5年的疗效观察

目的 观察近视眼患者准分子激光原位角膜磨镶术（laser in keratomileusis, LASIK）后5年中央角膜厚度及角膜曲率等的变化情况,并分析LASIK的安全性和远期疗效.方法 接受LASIK手术的近视患者52例（104只眼）,检查患者术后5年的视力、屈光状态、中央角膜厚度及角膜曲率,并与术前及术后早期数据进行比较.结果 术后5年均未发生继发性角膜扩张或医源性圆锥角膜;最佳矫正视力均无下降;平均等效球镜度数为（0.043±0.502）D,其中94眼为0～0.50 D,占90.38%.术后各阶段视力较稳定,等效球镜度数3个月时渐趋稳定.术后1年与术后5年中央角膜厚度差异无统计学意义（P〉0.05）,而各自与术后预计角膜厚度相比差异有统计学意义（P〈0.05）,均较术后预计角膜厚度厚;术后1～5年角膜曲率差异无统计学意义（P〉0.05）.结论 LASIK治疗近视具有良好的预测性和稳定的远期疗效.     

Intracorneal rings to correct corneal ectasia after laser in situ keratomileusis

PURPOSE: To evaluate the potential of using intrastromal corneal ring technology (Intacs, KeraVision) to correct posterior ectasia after laser in situ keratomileusis (LASIK) for myopia. SETTING: Department of Cornea and Refractive Surgery, Instituto Oftalmológico de Alicante, and Miguel Hernández University School of Medicine, Alicante, Spain. METHODS: In this prospective noncomparative intervention case series, Intacs segments were implanted in 3 eyes that developed posterior ectasia after myopic LASIK with clear central corneas. Posterior ectasia and corneal thickness were tested using the Orbscan II Slit Scanning Corneal Topography/Pachymetry System (Orbtek Inc.). Segment thickness varied based on corneal topography analysis and refraction. The mean follow-up was 8.3 months (range 7 to 11 months). RESULTS: The cases showed marked improvement after Intacs segment implantation. Postoperatively, there was a reduction in the magnitude of the posterior and anterior corneal surface steepening or ectasia and an increase in the topographical regularity index. In addition, the significantly enlarged optical zones resulted in a favorable visual outcome. In 2 eyes, the uncorrected visual acuity (UCVA) was 20/40 postoperatively. In the third eye, there was a residual refractive error; the UCVA was 20/50 and the best spectacle-corrected visual acuity, 20/40. CONCLUSIONS:Intacs intrastromal corneal rings used as a mechanical device may alter the biomechanical properties of the cornea for the correction of iatrogenic keratectasia and the associated residual myopia.     

Long-term results of laser in situ keratomileusis for high myopia: risk for ectasia

PURPOSE: To ascertain the long-term stability of laser in situ keratomileusis (LASIK) in highly myopic eyes. SETTING: Clinical practice office-based surgery. METHOD: Charts of eyes with high myopia who had LASIK surgery by the same surgeon between 1994 and 2000 were reviewed in 2003, and patients were given an appointment for follow-up examinations. In these highly myopic eyes, surgery was originally performed to create undercorrections with or without decreasing the ablation diameters to maximally conserve the residual stromal bed thickness. RESULTS: Of the 107 eyes with myopia between -10.00 diopters (D) and -35.00 D reviewed and operated on in a 3-year period between 1994 and 1998, 35 eyes of 31 patients had a single enhancement procedure. One case of ectasia as a result of excessive tissue removal occurred in a patient with a preoperative refraction of -28.00 D. Of the 107 eyes reviewed, 78 (73%) were examined after 5 years, 68 (63%) after 7 years, and 15 (14%) between 9 years and 11 years. CONCLUSIONS: Operating on eyes with highly myopic refractive errors and removing substantial tissue thickness did not produce ectasia in this series. Although high myopia has been considered a risk factor for post-LASIK ectasia, adherence to proper screening and intraoperative pachymetry appears to decrease the risk.     

Intraocular lens power calculation in eyes after corneal refractive surgery

PURPOSE: The purpose of this review article is to discuss the major reasons for postoperative hyperopia after cataract surgery following radial keratotomy (RK) and photorefractive keratectomy (PRK) and to illustrate potential methods for improvement of intraocular lens (IOL) power prediction after keratorefractive surgery based on exemplary model calculations. METHODS: We previously performed model calculations in eyes after PRK for myopia (-1.50 to -8.00 D, mean -5.40 +/- 1.90 D) using keratometry readings as measured by the Zeiss keratometer and the TMS-1 topography unit and as calculated using the "clinical history method" (spherical equivalent refraction change) and change in anterior surface keratometry readings. RESULTS: We found that after PRK, mean measured keratometry readings were significantly greater than respective calculated values considering the preoperative to postoperative change of anterior corneal surface (P < .001), which itself was significantly greater than calculated keratometry readings considering the preoperative to postoperative change of spherical equivalent refraction (P < .001). IOL power underestimation correlated significantly with the difference between preoperative and postoperative spherical equivalent refraction (P = .001). CONCLUSIONS: For correct assessment of keratometric readings to be entered into more than one modern third-generation IOL power calculation formula (but not a regression formula), the clinical history method should be applied whenever refraction and keratometric diopters before the keratorefractive procedure are available to the cataract surgeon. If preoperative keratometric diopters and refraction are not known, average central power on the postoperative videokeratograph may be used after RK, but refined calculation of keratometric diopters from radius of anterior and posterior corneal surface should be used after PRK and/or LASIK.     

LASIK矫正体表瘢痕疙瘩者近视的临床研究

目的：研究和观察准分子激光原位角膜磨镶术（LASIK）治疗体表伴瘢痕疙瘩近视患者的安全性、有效性和预测性。方法：前瞻性连续研究,在伦理委员会同意下,对16例32眼体表有瘢痕疙瘩的近视患者行LASIK矫正,年龄19～29（平均23.6）岁,裸眼远视力0.05～0.2,最佳矫正视力0.8～1.2,常规行裂隙灯显微镜,OrbscanⅡ眼前节分析系统、眼压、角膜厚度、电脑验光、散瞳检影、主观验光、对比敏感度和眩光等检查。患者均先行1眼手术,术后3mo无异常反应者再行对侧眼,术后随访2～6a,平均58.20±4.6mo。结果：术后2～6a,裸眼视力≥1.0者30眼（94%）,0.8者2眼（6%）。术后最佳矫正视力高于或等于术前者31眼（97%）,1眼有-0.75D屈光回退,术后屈光度与目标屈光度的差值平均为-0.25±0.35（-0.75～＋0.75）DS。角膜透明,层间无haze形成及瘢痕愈合,无角膜扩张及角膜明显增厚。结论：LASIK治疗瘢痕疙瘩近视患者安全、有效;同时也说明,角膜瓣与基质层间愈合非瘢痕性愈合,但需大样本长期随访进一步证明。     

智慧型光斑LASIK治疗近视临床分析

目的:探讨智慧型光斑LASIK治疗近视或近视散光可预测性、稳定性、有效性及术后残留屈光度危险因素分析。方法:回顾性分析2008-10/2009-10在我中心行LASIK病例,术前最佳矫正视力(BCVA)≥0.8,随访时间>1mo,球镜<-10.00D纳入统计分析病例,共768例。按激光切削模式及屈光度分组,对术后裸眼视力,术后1,3,6mo;1a残留等效球镜,屈光回退患者术前术后数据行统计学分析。结果:10例BCVA术后未达术前;预测性:术后常规组98.0%SE<0.50D,99.2%SE<1.00D;波前组97.4%SE<0.50D,99.3%SE<1.00D;术后残留屈光度,常规组:1mo:-0.01±0.10D;3mo:-0.02±0.20D;6mo:-0.07±0·31D;1a:-0.15±0.38D。波前组:1mo:-0.01±0.08D;3mo:-0.01±0.09D;6mo:-0.03±0.15D;1a:-0.08±0.19D;视力改变,常规组:0±0.05,波前组:0.01±0.04。23例术后残留屈光度危险因素分析,术后残留球镜与年龄,术前球镜有关,术后球镜=1.355-0.034年龄+0.142术前球镜;术后残留柱镜与术前柱镜,术前中央角膜厚度有关,术后柱镜=3.489+0.238术前柱镜-0.007术前中央角膜厚度。结论:智慧型光斑LASIK预测性,稳定性,有效性均较好,波前像差引导LASIK在预测性及有效性方面更优,两种术式均有较好的稳定性;术后残留球镜危险因素:年龄、术前球镜,术后残留柱镜危险因素:术前柱镜、术前中央角膜厚度。