准分子激光角膜切削术对角膜的影响

屈光不正是发病率较高的疾病之一,其手术治疗方法种类很多。近年发展起来的屈光性激光角膜切削术（ｐｈｏｔｒｅｆｒａｃｔｉｖｅｋｅｒａｔｅｃｔｅｏｍｙ,ＰＲＫ）和激光原位磨镶术（ｅｘｃｉｍｅｒｌａｓｅｒｉｎｓｉｔｕｋｅｒａｔｏｍｉｌｅｕｓｉｓＬＡＳＩＫ）已...     

准分子激光角膜切削术后视网膜脱离

准分子激光角膜切削术后视网膜脱离牛建军孙时英王黎波吴国夷刘晓荣兰州军区乌鲁木齐总医院眼科（８３００００）准分子激光角膜表面屈光性切除术（Ｐｈｏｔｏｒｅ－ｆｒａｃｔｉｖｅＫｅｒａｔｅｃｔｏｍｙ，ＰＲＫ）术后视网膜脱离少见，现将我们遇到的两例报告如下。例...     

准分子激光兔角膜切削术后细胞凋亡和增殖

目的 寻找准分子激光角膜切削术（ＰＲＫ）术后细胞凋亡和激活增殖的动态联系,评价激光去除上皮（ＰＴＫ）和机械刮除上皮（ＭＥＳ）对凋亡和增殖的影响。方法 对１８只兔按ＰＴＫ和ＭＥＳ行ＰＲＫ（－９．９０Ｄ,６．０ｍｍ直径）,术后定期用活体共聚焦显微镜观察及制作病理切片,ＴｄＴ介导ｄＵＴＰ缺口末端标记（ＴＵＮＥＬ）原位显示凋亡细胞,激光扫描共聚焦显微镜观察凋亡细胞形态,定量统计比较凋亡水平差别。结果 ＰＲ     

兔眼准分子激光近视角膜切削术后角膜膨出的研究

目的：探讨兔眼在准分子激光近视角膜切削术（Excimer laser in-situ keratomileusis,LASIK)手术后在不同的眼压下角膜膨出的程度。方法：26兔52眼随机分为对照组，LASIK手术组，单盲法，术前，术后测量角膜厚度和角膜地形图后，再将两组随机交叉分为正常眼压组，低度高眼压组，高度高眼压组，并观察1个月，用角膜地形图对实验前后的角膜形态进行分析。并应用统计学方法将手术切削量和眼压两个因素对角膜扩张的影响做双因素方差分析。结果：LASIK手术的角膜切削量，术后高眼压以及两者的交互效应对角膜抵抗力都有显著影响。较大的切削量和术后持续高眼压后的兔眼角膜地形图经分析符合圆锥角膜模式，并出现前，后弹力膜断裂的形态学改变。结论：角膜较大的切削量和术后持续的高眼压是导致兔眼LASIK术后发生圆锥角膜的重要原因。     

准分子激光屈光性角膜切削术对角膜内皮细胞的影响

目的 探讨分析准分子激光屈光性角膜切削术（ＰＲＫ）治疗近视后对角膜内皮细胞的影响。方法 对１０１只眼ＰＲＫ术后者,用接触型镜面反光角人皮显微镜（Ｋｏｎａｎ ＳＰ－３５００型,日本）检测不同部位角膜内皮细胞,并统计分析其在不同度数范围内的平均细胞密度、细胞面积的变异系数和六角形细胞的百分率。结果 平均细胞密度在Ｃ组上降１０％,Ａ,Ｂ组的下降无统计学意义。细胞面积的变异系数及六角形细胞百分率均下降１０     

准分子激光屈光性角膜切削术后角膜地形图分析

目的分析准分子激光屈光性角膜切削术（ｐｈｏｔｏｒｅｆｒａｃｔｉｖｅｋｅｒａｔｅｃｔｏｍｙ,ＰＲＫ）术后角膜切削区的形态、偏心情况和屈光的稳定性。方法对３１２例（３６６只眼）ＰＲＫ手术患者进行术后１、３和６个月的角膜地形图检查。结果术后１个月切削区中心偏离瞳孔中心的距离为０．２６６ｍｍ,双眼平均偏离瞳孔中心的方向均为鼻上侧。切削区形态平滑型占４９．５％,半环型、钥匙洞型、肾型和哑铃型占４２．９％,中心岛型占６．０％。中心岛型对术后最佳矫正视力影响较大。术后１～３个月角膜屈折力变化较大,高度近视比低度近视回退明显。结论提示ＰＲＫ术中瞄准中心问题非常重要,直接影响术后的效果,同时也应长期随访角膜地形图,进一步观察术后的稳定性。     

准分子激光角膜切削术后视网膜脱离

准分子激光角膜切削术后视网膜脱离北京同仁医院（１００７３０）齐颖王光璐李志辉魏文斌陆文秀孟玉玲自１９９３年我院行准分子激光角膜切削术（ＰＲＫ）治疗高度近视（＞－９Ｄ）资料完整者约９０例１７０眼，３眼发生视网膜脱离（ＲＤ），发生率１．７６％，其中１例为...     

准分子激光角膜切削术后角膜混浊的初步临床观察

对我院1995年2月-6月397例（738眼）近视患者行准分子激光角膜切削术治疗，随访6－10月的126例（239眼）进行观察发现，术后角膜混浊2级以上影响视力恢复盲占3．77%。角膜混浊的发生与性别、年龄、屈光度和切削深度无关，可能与屈光回退，末使用皮质类固醇和个体差异有关。在术后随访6－10月，绝大多数角膜混浊逐渐减轻。本组病例PRK手术效果初步观察表明，这是治疗近视的一种比较安全有效的方法。     

角膜地形图在准分子激光角膜切削术中的应用

角膜地形图的问世，使人们系统地、精确地了解角膜性 状成为可能。本文参考大量文献，就角膜地形图的构成原理与特性、正常角膜的角膜地形图表现，圆锥形角的筛选及角膜地形图对ＰＲＫ手术疗效的评价等方面进行综述。     

准分子激光角膜切削术前后角膜地形图对比分析

应用角膜地形图仪对比分析了９０例（１７６眼）ＰＲＫ手术前后角膜表面的形态特征及其变化。结果表明,术前角膜地形图以蝴蝶结形为多（７３．３％）;术后７９．０％为圆形或钥匙孔形,半圆形和蝶形为１８．８％中央岛形占２．２％。ＰＲＫ对散光的一次最大矫正量为－１．７５Ｄ,切削中心偏位是最佳矫正视力下降,复视和屈光度回退的重要原因。提示：ＰＲＫ术后角膜地形图的检查可准确显示角膜形态的细微变化,有利于手术设计的不断完善和效果的提高。     

丝裂霉素C对准分子激光屈光性角膜切削术后角膜混浊的实验研究

目的探讨丝裂霉素Ｃ对准分子激光屈光性角膜切削术后角膜上皮下雾状混浊（ｈａｚｅ）的影响。方法对４５只新西兰白兔的双眼行准分子激光屈光性角膜切削术,术中、术后分别给予０．００８％丝裂霉素Ｃ、０．１％地塞米松治疗及空白对照。术后分别进行裂隙灯、角膜内皮镜、光镜和透射电镜检查。结果术后４及８周,丝裂霉素Ｃ组角膜ｈａｚｅ轻于对照组和地塞米松组;地塞米松组轻于对照组。术后１、４及８周,丝裂霉素Ｃ组术区前基质内角膜细胞数较对照组和地塞米松组少,后两组间差异不明显。三组间角膜上皮愈合时间、角膜上皮厚度及内皮细胞密度差异无显著性（Ｐ＞０．０５）。结论丝裂霉素Ｃ能通过抑制角膜细胞的生长而减轻ｈａｚｅ的形成,其效果优于地塞米松,且无明显副作用,是一种较理想的抑制ｈａｚｅ形成的药物     

准分子激光屈光性角膜切削术治疗高度近视探讨

目的探讨准分子激光角膜切削术(PRK)治疗高度近视的效果.方法应用VISX20/20B型准分子激光仪,采用多光区切削法治疗-15D以上超高度近视.术后随访19～38月,并对结果进行分析.结果术前最佳矫正视力0.69±0.19,术后裸眼视力0.61±0.11.术后3月左右角膜上皮下混浊(haze)明显,1年后最轻,该组haze平均(0.53±0.17)级,屈光度回退平均(3.15±1.56)D.结论对于角膜较薄,不适于准分子激光原位角膜磨削术(LASIK)的超高度近视患者,PRK的多光区切削方式仍不失为一种安全、有效且稳定性较好的方法.     

丝裂霉素C与地塞米松治疗PRK后角膜上皮下雾状混浊的对比实验研究

目的　探讨滴用丝裂霉素 C溶液治疗准分子激光屈光性角膜切削术 (excim erlaser photorefractive keratectom y,PRK)后角膜上皮下雾状混浊 (haze)的作用 ,并与地塞米松溶液对比。方法　对 4 1只新西兰白兔双眼行 PRK,术后分别给予 0 .2 g· L- 1丝裂霉素 C和 1.0 g· L- 1地塞米松滴眼治疗及平衡盐液滴眼作为对照 ,并行裂隙灯、角膜内皮镜、光镜、电镜检查。结果　术后 4、8周 ,丝裂霉素 C组与地塞米松组 haze程度相同 (P>0 .0 5 ) ,均较对照组为轻 (P<0 .0 5 )。光镜及电镜检查表明 :对照组术区角膜上皮细胞过度增生 ,前基质成纤维细胞增生活跃 ,纤维排列明显紊乱 ;而丝裂霉素 C组与地塞米松组角膜上皮细胞和前基质成纤维细胞的增生以及胶原纤维合成均受抑制 ,纤维排列较整齐。结论　丝裂霉素 C能减轻 PRK后 haze,且无明显副作用 ,可望成为防治 haze的一种新药     

Contrast sensitivity after excimer laser photorefractive keratectomy for myopia

AIM: To evaluate contrast sensitivity in patients who had undergone uncomplicated excimer laser photorefractive keratectomy (PRK) for myopia. · METHODS: Monocular contrast sensitivity function was measured with the CSV-I000E chart in 41 patients who had received PRK by the Nidek EC-5000 excimer laser system. Mean preoperative refractive error was -2.62±1.33 D (range, -0.75 to -4.00 D). Contrast sensitivity function was measured preoperatively, 1week, 1, 3 and 6 months after surgery through the CSV-1000E contrast sensitivity unit (VectorVision). · RESULTS: Logarithmic values of contrast sensitivity at each spatial frequency were used for statistical analysis and normalized values were used for graphical representation. Contrast sensitivity decreased 1 week and 1 month postoperatively. Starting from the first month, there was rapid recovery of contrast sensitivity especially at low spatial frequencies, and at the third month, only at 6 and 12 cycles per degree (cpd) statistically significant decrease was seen. Six months after surgery, there was an increase in contrast sensitivity values at all spatial frequencies. · CONCLUSION: Photorefractive keratectomy can induce significant reductions in contrast sensitivity in the first month after surgery; these values returned to the preopereative values at 6 months after surgery.     

近视眼准分子激光角膜切削术后的对比敏感度评价

目的:评价近视患者PRK术后的对比敏感度变化.方法:应用CSV-1000E图表对41例接受Nidek EC-5000型准分子激光仪行PRK手术的患者,行单眼对比敏感度测量.患者术前平均屈光度为-2.62±1.33D(范围从-0.75至-4.00D).应用CSV-1000E对比敏感度仪分别在术前,术后1wk;1,3,6mo行对比敏感度检查.结果:将每个空间频率的对比敏感度对数值进行统计学分析,并应用图表与正常值进行比较.结果显示对比敏感度在术后1wk及术后1 mo时明显降低,从第1 mo开始,对比敏感度尤其是低空间频率的对比敏感度快速恢复,在第3mo,只有6和12cpd两种空间频率的对比敏感度明显降低,在术后6mo时,所有频率的对比敏感度功能都明显增加.结论:PRK术后患者第1 mo对比敏感度功能明显降低,但在术后6mo时对比敏感度功能即恢复至术前水平.     

准分子激光屈光性角膜切削术后的再治疗

目的 评价准分子激光屈光性角膜切削术（ｐｈｏｔｏｒｅｆｒａｃｔｉｖｅ ｋｅｒａｔｅｃｔｏｍｙ,ＰＲＫ）术后因屈光回退,欠矫出现的残留近视及严重角膜上皮下雾状混沌（ｈａｚｅ）而再次手术治疗的疗效及安全性。方法 采用准分子激光仪对－１．００～－１６．５０Ｄ的近视眼及近视散光患者进行治疗。ＰＲＫ术后３５例（５１只眼）患者出现残留近视及严重ｈａｚｅ。结合ＰＲＫ手术及准分子激光治疗性角膜切削术（ｐｈｏｔｏｐ     

雷帕霉素对兔眼准分子激光角膜切削术后haze的影响

目的:探究调节自噬活性对兔眼准分子激光角膜切削术(PRK)术后角膜上皮下雾状混浊(haze)的影响.方法:新西兰大白兔64只行右眼PRK手术后,根据术后局部用药不同,随机分为4组:单纯手术组、14μmol/L二甲基亚砜组(DMSO)、50μmol/L雷帕霉素组、100μmol/L雷帕霉素组,每组16只.根据分组情况,术...     

准分子激光屈光性角膜切削术角膜神经损伤及再生的形态学研究

２２只新西兰白兔（４０眼）行－５．５０Ｄ，５．５ｍｍ直径的近视ＰＲＫ，术后不同时期取角膜进行氯化金染色以观察角膜神经的损伤及再生。ＰＲＫ术后切削区内上皮下神经丛被切除，术后１周可见神经纤维再生，２个月时新生神经纤维密度高于正常，术后３—４个月其密度达高峰，到术后６个月时角膜中央区神经再生过程尚未全部完成。结果表明，ＰＲＫ可以损伤切削区角膜神经，其再生在术后早期即可发生，但神经的修复还需一个较长的时间过程。     

Confocal microscopy reveals persisting stromal changes after myopic photorefractive keratectomy in zero haze corneas

AIMS—Micromorphological examination of the central cornea in myopic patients 8-43 months after excimer laser photorefractive keratectomy (PRK), using the slit scanning confocal microscope.
METHODS—Patients were selected from a larger cohort of individuals on the basis of full corneal clarity (haze grading 0 to +1; mean 0.3) and their willingness to participate in the study. 15 eyes of 10 patients with myopic PRK (−4 to −11 D; mean 6.7) and an uneventful postoperative interval of 8-43 months (mean 26) were examined. Contact lenses had been worn by eight of the 10 patients for 4-11 years (mean 6.7) before surgery. Controls included the five untreated fellow eyes of PRK patients, 10 healthy, age matched volunteers without a history of ocular inflammation or contact lens wear, and 20 patients who had worn rigid gas permeable (n=10) or soft contact lenses (n=10) for 2-11 years. Subjects were examined with a real time flying slit, scanning confocal microscope using ×25 and ×50 objectives.
RESULTS—In PRK treated patients and contact lens wearers, basal layer epithelial cells sporadically displayed enhanced reflectivity. The subepithelial nerve plexus was observed in all individuals, but was usually less well contrasted in the PRK group, owing to the presence of a very discrete layer of subepithelial scar tissue, which patchily enhanced background reflectivity. Within all layers of the stroma, two distinct types of abnormal reflective bodies were observed in all PRK treated eyes, but in none of the controls. One had the appearance of long (>= 50 µm), slender (2-8 µm in diameter) dimly reflective rods, which sometimes contained bright, punctate, crystal-like inclusions, arranged linearly and at irregular intervals. The other was shorter (<25 µm), more slender in form (<1 µm in diameter), and highly reflective; these so called needles were composed of crystal-like granules in linear array, with an individual appearance similar to the bright punctate inclusions seen in rods, but densely packed. Both of these unusual structures were confined, laterally, to the ablated area, but were otherwise distributed throughout all stromal layers, with a clear predominance in the anterior ones. These rods and needles were observed in all PRK treated corneas, irrespective of previous contact lens wear. On the basis of qualitative inspection, the incidence of rods and needles did not appear to correlate with either the volume of tissue ablated or the length of the postoperative interval. In contact lens wearing controls, highly reflective granules, reminiscent of those from which the needles were composed, were found scattered as isolated entities throughout the entire depth and lateral extent of the corneal stroma, but rods and needles were never encountered. The corneal endothelium exhibited no obvious abnormalities.
CONCLUSION—Confocal microscopy 8-43 months after PRK revealed belated changes in the corneal stroma. These were manifested as two distinct types of abnormal reflective bodies, which had persisted beyond the stage when acute wound healing would have been expected to be complete. The clinical significance of these findings in the context of contrast visual acuity and long term status of the cornea is, as yet, unknown.

Keywords: photorefractive keratectomy; excimer laser; confocal microscopy; stromal pathology