准分子激光角膜切削术后屈光回退角膜地形图与屈光度变化的关系

不论是ＰＲＫ还是ＬＡＳＩＫ治疗近视术后都有屈光回退的可能。为探讨屈光回退的原因 ,我们应用计算机辅助角膜地形图对 6 6眼屈光回退患者进行检查并比较分析。1　资料与方法1.1　本组 130例 2 5 0眼 ,准分子激光治疗后发生屈光回退 6 6眼占 2 6 40 %。术前及术后 6月以上进行美国产ＥｙｅＳｙｓ角膜地形图仪检查 ,依ＨｏｌｌａｄａｙＤｉａｇｎｏｓｔｉｃＳｕｍｍａｒｙ中ＡｖｇＳｉｍＫ为角膜曲率值 ,电脑及视网膜检影验光 ,得出屈光回退患者手术前后角膜曲率变化和临床屈光度变化 ,以及术后角膜曲率变化值和屈光回退值。将数据输入计算…     

角膜地形图对准分子激光屈光性角膜手术后散光变化的判断作用

目的 探讨准分子激光我性角膜手术前后角膜地形图△ＳｉｎＫ变化值在散光度数变化判断中的作用。方法 对近视度为－１．５０～－２４．００Ｄ,散光度数－０．７５～－５．５０Ｄ的患者８９例１５０眼行准分子激光屈光性角膜切削术（ＰＲＫ）或分子激光原位角膜磨削术（ＬＡＳＩＫ）,观察６个月以上,经计算机得出角膜曲率△ＳｉｎＫ变化值Ｘ与临床散光度数变化 值Ｙ的散点图及相关系数ｒ值。结果 手术前后Ｘ与Ｙ的关系：Ｙ＝１     

影响准分子激光屈光性角膜切削术后眼压的因素

目的分析影响准分子激光屈光性角膜切削术（ｅｘｃｉｍｅｒｌａｓｅｒｐｈｏｔｏｒｅｆｒａｃｔｉｖｅｋｅｒａｔｅｃｔｏｍｙ,ＰＲＫ）术后眼压的因素。方法采用非接触式眼压计（ｎｏｎｃｏｎｔａｃｔｔｏｎｏｍｅｔｒｙ,ＮＣＴ）测量眼压,对ＰＲＫ前、后随访半年以上８６例（１５０只眼）患者眼压差与角膜切削厚度、术前术后角膜曲率差之间进行多元回归分析。结果术前眼压明显高于ＰＲＫ术后１周、３及６个月的眼压,差异有非常显著性（ｔ检验,Ｐ＜０．０１）,与术后１个月时眼压比差异无显著性（Ｐ＞０．０５）。术后１个月时的眼压高于术后其他时间眼压（Ｐ＜０．０１）。ＰＲＫ后眼压降低与角膜厚度减少及角膜前表面曲率的降低有关（ｒ＝０．３６１,Ｐ＜０．０１;ｒ＝０．１８８,Ｐ＜０．０５）,建立二元回归方程如下：Ｙ＝－０．０５９－０．０３８Ｘ１＋０．００９Ｘ２。Ｙ：术前术后眼压差（ｋＰａ）,Ｘ１：术前术后角膜曲率差（Ｄ）,Ｘ２：角膜切削厚度（μｍ）。结论ＰＲＫ后ＮＣＴ测量眼压低于术前,术后眼压与氟甲脱氧泼尼松龙（ｆｌｕｏｒｏｍｅｔｈｏｌｏｎｅ）的用药次数和时间、角膜切削厚度、角膜曲率有关。     

准分子激光角膜切削术后散光的角膜地形图分析

了解准分子激光角膜切削术（ｐｈｏｔｏｇｒａｃｔｉｖｅｋｅｒａｔｅｃｔｏｍｙ，ＰＲＫ）前、后最大轴性散光的变化及对术后视力的影响。方法对ＰＲＫ后１年以上的６１例（１０９只眼）术前散瞳验光散光度一１．００～－２．００Ｄ的角膜地形图进行分析及视力检查。结果散瞳验光散光轴位与地形图记录散光轴位基本一致，而散光度数有一定差异。地形图检查显示，最大散光轴位以循规性极光最多，计６７只眼（６１％），斜轴性散光３６只眼（３３％），逆规性散光６只眼（６％）。手术前、后散光轴位变化极小。散光度多数在术后１０天及１个月开始增加，以后逐渐减少。６个月或１年趋于稳定。术后的残存散光对视力影响较小，实际矫正度在预期矫正度±１．００Ｄ以内者占９７％。结论采用球柱折算方法，进行ＰＲＫ，对矫正近视合并散光者（－２．００Ｄ以下），可以获得满意的屈光矫正。     

角膜外伤术后的角膜地形图分析

眼外伤、手术均可使角膜屈光状况、角膜内皮发生改变。本文对１６例３２只眼角膜裂伤术后伤眼与健眼进行了角膜地形图检查。发现角膜平均表面规则系数ＳＲＩ为３．４５８３±２．２９，平均表面不规则系数ＳＡＩ为２．２７３６±１．９０，角膜外伤术眼与健眼ＳＲＩ及ＳＡＩ均有显著性差异（Ｐ＜０．０１）。角膜外伤术眼的角膜地形图ＳｉｍＫ差值为５．７１６７±４．２５１８，健眼ＳｉｍＫ差值为１．５４１７±２．９６１１，二者存在显著性差异（Ｐ＜０．０１）。对评价手术的安全性，术中操作技巧及判定预后有着重要价值     

准分子激光角膜切削术治疗近视散光的角膜地形图分析

应用计算机辅助的角膜地形图分析系统对１５例（３０眼）近视散光患者于准分子激光角膜切削术（ＰＡＲＫ）后进行角膜地形图的检测分析,发现ＰＡＲＫ术后角膜表面的球面性状发生一定的改变：ＳＲＩ无显著性改变而ＳＡＩ有显著性改变;ＳｉｍＫ及ＳｉｍＫ的差值均有显著性改变。术后３个月检查时,角膜地形图主要表现为四种形态：圆形或椭圆形（４６．７％）、哑铃形（２６．７％）、半环形（１０．０％）、中央小岛形（１６．７％）,且各种形态与最佳视力有着一定的关系。由此证明,角膜地形图的定量分析对ＰＡＲＫ术后角膜表面球面性状的评价、手术设计的改进、手术疗效的预测等有重要的临床意义。     

角膜曲率计在测量角膜散光中的作用

目的 :探讨角膜曲率计检查在测量角膜散光中的作用。方法 :采用角膜曲率计、散瞳验光、显然验光三种方法对屈光不正患者 2 2 4只眼进行检查。结果 :本组病例中散光度数以 1 0 0D以下为主。散瞳验光和显然验光所测出的散光轴位与角膜曲率计所测出的散光轴位比较 ,差异无显著性 (P >0 0 5)。在散光度数上 ,散瞳验光和显然验光测出的散光度数与角膜曲率计所测出的散光度数比较 ,差异有非常显著性 (P <0 0 1 )。散瞳验光与显然验光之间在散光度数上比较 ,差异无显著性 (P >0 0 5)。结论 :角膜曲率计对于散光轴位的测量在散瞳验光和显然验光中起到重要的辅助作用     

LASIK术后角膜三维形态的改变及与临床屈光度的关系

目的应用裂隙扫描角膜地形图／角膜测厚系统（Ｏｒｂｓｃａｎ）评估高度近视眼ＬＡＳＩＫ术后角膜三维形态的改变以及探讨角膜屈光力改变和屈光度矫正之间的关系。方法选择行ＬＡＳＩＫ手术的高度近视眼４７例９１眼，应用Ｏｒｂｓｃａｎ系统进行术前、术后３月的角膜形态观察，分析角膜屈光力改变与眼球总体屈光力变化的相关性。结果高度近视眼前表面３　ｍｍ区平均曲率为４８．４９　Ｄ±１．２５　Ｄ，后表面３　ｍｍ区为－６．５　Ｄ±０．２３　Ｄ。术后３月平均矫正屈光度为６．６２　Ｄ±２．２１　Ｄ，前表面３　ｍｍ区平均曲率为４３．０２　Ｄ±１．２５　Ｄ，后表面３　ｍｍ区为－６．９　Ｄ±０．２４　Ｄ，与术前比较有显著性意义（Ｐ＜０．０５）。术后５　ｍｍ区与３　ｍｍ区的角膜屈光力差值明显比术前增大，差异有显著性意义（Ｐ＜０．０１）。术后角膜总屈光力改变平均值为５．８７　Ｄ±１．２１　Ｄ，与术后眼总体屈光力改变存在显著正相关（ｒ＝０．９５７　１，Ｐ＜０．０１）。结论Ｏｒｂｓｃａｎ能全面评估角膜屈光手术后三维形态的改变，对角膜屈光手术后白内障患者正确选择人工晶状体度数具有指导意义。     

准分子激光屈光性角膜切削术矫正散光的准确性及预测性

目的 探讨准分子激光屈光性角膜切削术（ｅｘｃｉｍｅｒ ｌａｓｅｒ ｐｈｏｔｏｒｅｆｒａｃｔｉｖｅ ｋｅｒｅｃｔｏｍｙ,ＰＲＫ）矫正散光的准确性及预测性。方法 根据角膜地形图提供的角膜屈光力数值,用Ｈｏｌｌａｄａｙ法计算复性近视散光３０例（５３只眼）和单纯近视２３例（３３只眼）患者术前与术后６个月角膜屈光力的差值,确定实际矫正散光度及轴位,及预期矫正散光度及轴位进行对比分析。结果 复性近视散光组５３     

准分子激光屈光性角膜手术后角膜知觉的改变

目的观察和分析准分子激光屈光性角膜切削术（ｐｈｏｔｏｒｅｆｒａｃｔｉｖｅｋｅｒａｔｅｃｔｏｍｙ，ＰＲＫ）和准分子激光原位角膜磨镶术（ｌａｓｅｒｉｎ－ｓｉｔｕｋｅｒａｔｏｍｉｌｅｕｓｉｓ，ＬＡＳＩＫ）治疗近视后角膜知觉的变化。方法对２３１例（３８７只眼）近视患者施行ＰＲＫ，对４８２例（７９６只眼）施行ＬＡＳＩＫ进行治疗。对术后角膜知觉不同时期的变化进行检查、分析。结果ＰＲＫ和ＬＡＳＩＫ术后早期角膜知觉均明显下降，尤以ＰＲＫ明显。ＰＲＫ术后角膜知觉在术后６个月才能恢复，ＬＡＳＩＫ术后角膜知觉约在术后１个月即恢复。结论ＰＲＫ术后角膜知觉的恢复比ＬＡＳＩＫ慢。     

角膜地形图在儿童散光检影验光中的应用

通过比较儿童验光中角膜地形图所测得的角膜散光与检影验光测得的散光的相互关系,探讨角膜地形图检查在儿童散瞳检影验光中的应用价值。 方法：采用计算机辅助的角膜地形图和散瞳检影验光两种测量方法,对88例171眼非混合性散光眼进行检查并比较。 结果：两种方法在检查散光度数及散光轴方面差异无统计学意义(t=1.838,P＞0. 05;t=1.009,P＞0.05),实际最好矫正视力与角膜地形图PVA高值及低值比较差别有统计学意义（t=3.566,P＜0.01;t=3.445,P＜0.01)。 结论:角膜地形图检查所得的散光度数及轴向可为散瞳检影验光提供重要的参考依据,角膜地形图检查在提高低龄儿童散瞳检影验光速度和准确度有一定作用。     

角膜曲率计测量的角膜散光与静态总合眼散光在病理性散光儿童中的对照研究

目的 明确在散光儿童中通过角膜散光预测总合眼散光的可靠性,证实角膜曲率计行儿童子午线弱视初步筛查的可行性.方法 随机抽取1005名(1910只眼)4～8岁的病理性散光儿童,比较用角膜曲率计测定的角膜散光与用阿托品眼膏行睫状肌麻痹后静态检影测定的总合眼散光之间的差异.结果 (1)角膜散光绝对值与总合眼散光的绝对值呈直线正相关关系,相关系数r =0.771 (P＜0.001).(2)按角膜散光度的高低分为5组(组间散光值跨度为1D),组1(散光值为0～0.99D)的角膜散光度均值较总合眼散光度均值低0.27D(P＜0.05),组5(散光值≥4D)的角膜散光度均值较总合眼散光度均值高0.43D(P＜0.05),其它各组的角膜散光度均值与总合眼散光度均值间差异无统计学意义(P＞0.05).结论 通过角膜曲率计测量的角膜散光度可以预测总合眼散光程度,角膜曲率计用于大面积筛查初步了解儿童的散光状态并对儿童子午线弱视进行初步筛查具有可行性.     

LASIK/PRK术后人工晶状体度数计算的研究进展

随着屈光不正患者数量的增加及角膜屈光手术的盛行,越来越多早期选择角膜屈光手术(LASIK/PRK)矫正高度近视的患者如今面临着白内障手术,然而,用常规方法计算这部分患者的人工晶状体度数往往是不精确的。目前的第三代和第四代公式过高地估计了角膜屈光力,导致人工晶状体度数矫正不足,从而出现术后的远视漂移。而传统的角膜地形图采用2.5～3.2mm范围环上的角膜计算角膜屈光力,忽略了角膜中央的真实曲率,导致角膜屈光术后尤其是偏中心切削患者术后出现严重的屈光误差。本文旨在总结LASIK/PRK术后患者人工晶状体度数计算最新的误差来源以及最新计算方法,为提高屈光术后患者人工晶状体度数计算的准确性提供更多的选择。     

Laser in situ keratomileusis versus photorefractive keratectomy in the correction of myopic astigmatism

PURPOSE: To evaluate retrospectively the effectiveness of astigmatism correction in eyes treated with laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK). METHODS: Patients with low to moderate myopia with astigmatism ranging from +0.25 to +4.50 diopters were included in the study. PRK was performed on 62 eyes and LASIK on 70 eyes. Six-month data were analyzed with regard to astigmatism power, astigmatism axis, spherical equivalent, uncorrected visual acuity, vector astigmatism change, and topographic corneal regularity. RESULTS: Mean astigmatism magnitude change was 0.54 +/- 0.76 in PRK-treated eyes and 0.60 +/- 0.67 in LASIK-treated eyes (61% versus 64% change, respectively, p = 0.61) at 6 months after surgery. Mean spherical correction change was -2.79 +/- 1.51 for PRK and -2.90 +/- 1.03 for LASIK (p = 0.63). Mean spherical equivalent change was -2.5 +/- 1.57 for PRK and -2.6 +/- 1.23 for LASIK (p = 0.73). Mean change in astigmatism axis was 20.8 +/- 73.1 for PRK and 33.8 +/- 81.7 for LASIK (p = 0.34). Mean change in uncorrected visual acuity (LogMar) was 0.84 +/- 0.26 for PRK and 0.89 +/- 0.23 for LASIK (p = 0.21). Mean vector-corrected astigmatism change was 0.88 +/- 0.66 for PRK and 0.95 +/- 0.59 for LASIK (p = 0.51). Mean vector-corrected astigmatism axis for PRK was 86.9 +/- 59 degrees and for LASIK 83.8 +/- -47.6 degrees (p = 0.75). CONCLUSION: There was no significant difference in astigmatism correction between PRK and LASIK at 6 months after surgery.     

PRK、LASIK术后角膜地形图的变化对视力恢复的影响

目的：探讨准分子激光角膜切削术（photorefractive keratectomy,PRK)与准分子激光原位角膜磨镶术（laser insitu keratomileusis,LASIK)前后角膜地形图的变化及其与裸眼视力的关系。方法：采用EyeSys2000型角膜地形图系统测量PRK、LASIK术前及术后10天，1、3、6、12及24个月时的角膜地形图并记录同期的视力。结果：角膜地形图显示术后切削形态随着时间延长，趋于规则，Simk的差值和等效值，PRK组和LASIK组术前与术后相比都有显著性差异，术后偏心距离均在1.00mm内，术后裸眼眼力≥0．6，结论：在低、中度近视中，LASIK术后的偏心程度较PRK的稍重，引起裸眼视力偏低。     

Changes in central corneal thickness after laser in situ keratomileusis and photorefractive keratectomy

PURPOSE: To evaluate changes in corneal thickness after laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) in eyes with the same preoperative refraction, correlate these changes to postoperative refractive outcomes, and compare corneal healing process in a standardized subset of patients. METHODS: Central corneal thickness was measured by contact ultrasound pachymetry in 14 eyes of 8 patients with preoperative myopia of -6.00 D who had LASIK, and in 14 eyes of 8 patients with the same preoperative refractive error who had PRK. Measurements were taken preoperatively, and 1 week, 3, and 6 months after surgery. Data were evaluated and compared using the paired Student t-test and Pearson correlation coefficient. RESULTS: Mean preoperative central corneal thickness in the LASIK group was 549.14 +/- 37.4 microm, and in the PRK group, 552.64 +/- 34.9 microm. At 1-week postoperatively, mean central corneal thickness in the LASIK eyes was 467.28 +/- 29 microm and in the PRK eyes, 473.85 +/- 39.2 microm; at 6 months, central corneal thickness had increased in both groups compared to the 1-week values; LASIK eyes had a mean central corneal thickness of 481.42 +/- 23.0 microm and PRK, 481.50 +/- 35.3 microm. Mean postoperative refraction after 6 months was -0.48 +/- 0.30 D in the LASIK group and -0.67 +/- 0.35 D in the PRK group. CONCLUSION: Increase in central corneal thickness between 1 week and 6 months postoperatively occurred in both LASIK and PRK eyes, but differences were not statistically significant. No statistically significant differences were found in myopic regression between the two patient groups.     

Corneal power determination after previous corneal refractive surgery for intraocular lens calculation

PURPOSE: To assess the accuracy of different corneal power determination methods in patients who had undergone myopic laser in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), and radial keratotomy (RK). METHODS: The results for 208 eyes of 116 patients who had had corneal refractive surgery (LASIK, PRK, RK) for myopia were analyzed retrospectively. Keratometry measurements, i.e., autokeratometry readings (K(meas)), simulated keratotopography readings (Sim-K), and topographically measured average central corneal power in a 3-mm zone (ACP) were compared with calculated refraction-derived keratometric value. Correction factors based on the difference between measured and calculated keratometric powers were rated. RESULTS: Direct power measurements with standard keratometers and planokeratotopography systems overestimate corneal power after myopic PRK and LASIK. The average K(meas) and K(topo) were significantly greater than the average calculated refraction-derived keratometric values. Corneal power overestimation correlated significantly with the spherical equivalent change after refractive surgery (p < 0.001). After RK, there is no significant correlation of the difference between all measured K values and refraction-derived power with the spherical equivalent change. In these cases, the Sim-K value seems the most accurate among measured keratometric powers. The precision of measurement significantly depends on the parameters of the autokeratometer (i.e., measurement place, number of measurement points, keratometric index of refraction). CONCLUSIONS: To avoid underestimation of intraocular lens power after cataract surgery in the eyes that had previously undergone myopic corneal refractive surgery, the measured corneal power must be corrected. Although correction factors may be calculated for cases after PRK and LASIK, there are no universal and absolutely reliable methods to determine corneal power in these cases. More than one accessible method should be used, and the lowest, most reliable data should be used.     

LASIK手术治疗-2.0D以上散光的角膜地形图分析

目的 利用角膜地形图评价LASIK治疗-2.0D以上散光疗效的准确性.方法 对25例(36只眼)散光度在-2.0D以上的近视散光患者于LASIK手术前后行角膜地形图和主觉验光检查,并将主觉验光测得的散光值换算成角膜平面的散光值,随访6月以上,比较手术前后角膜地形图测得的角膜散光的改变情况以及主觉验光所得的散光改变.结果 手术前后平均角膜地形图散光大小分别为(-2.29±0.61)D和(-1.91±0.68)D,主觉验光手术前后平均角膜平面的散光大小分别为(-2.22±0.61)D和(-0.46±0.43)D,两者手术前后差异均有统计学意义(P<0.05);手术前后平均角膜地形图散光轴位改变(3.19±3.04)度,手术前后显性散光轴位改变(29.61±29.49)度;术前角膜地形图散光和术前显然验光角膜平面的散光大小差异无统计学意义(P>0.05),散光轴位平均差异为(6.53±14.19)度,而术后角膜地形图散光和术后显然验光角膜平面的散光大小差异有统计学意义(P=0.00).结论 角膜地形图测量术前-2.0D以上散光与主觉验光结果基本一致,但LASIK术后,角膜地形图往往高估术后的散光值.     

Excimer laser refractive correction of myopia after episcleral buckling for rhegmatogenous retinal detachment

PURPOSE: To evaluate the long-term effects of excimer laser treatment for ametropia after surgical treatment of rhegmatogenous retinal detachment (RRD) with scleral buckles. SETTING: Helsinki University Eye Hospital, Helsinki, Finland. METHODS: Ten patients (10 eyes) who had 1 or more surgeries for RRD followed by refractive surgery for myopia were retrospectively enrolled in this study and were examined after excimer laser refractive surgery. Photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK) was performed using a Star S2 excimer laser system (Visx). The best spectacle-corrected visual acuity (BSCVA), refraction, degree of anisometropia, and topographical changes were evaluated before and after the surgeries. RESULTS: All patients were free of asthenopic symptoms after refractive surgery. At the end of the follow-up, a mean of 67 months +/- 14 (SD) after refractive surgery, 6 patients were within +/-1.0 diopter of the intended correction. Compared with previously reported cohorts of myopic patients, the achieved refraction in patients who previously had a scleral buckling procedure was worse. The postoperative refraction was stable, and corneal topography did not show induced scar formation, keratectasia, or irregular astigmatism. After refractive surgery, the BSCVA improved 1 Snellen line in 3 patients and 2 lines in 1 patient. One patient lost 1 Snellen line and another patient lost 2 lines. Four patients showed no changes. New retinal complications were not observed. CONCLUSIONS: In the long-term, PRK and LASIK were safe methods for the treatment of myopia in RRD patients after scleral buckling. The predictability of myopic LASIK/PRK may be worse than generally reported in myopic cohorts.