电脑验光仪、角膜曲率计、检影验光测量散光的比较

目的:比较电脑验光仪、角膜曲率计和检影验光检查角膜散光三种方法。方法:采用电脑验光仪、角膜曲率、检影验光三种方法对屈光不正患者169例(338眼),进行检查。结果:本组病例中散光度数以3.50D以下为主,顺规性散光125例(250眼),占74.5%。逆规性散光44例(88眼),占25.5%。三者测出散光轴位比较,散光轴位基本相同,其中以电脑验光最准,差异无显著性(P>0.05)。三者测出散光度数比较,差异有非常显著性(P<0.01)。结论:电脑验光、检影验光对散光轴位和度数测量各有优点、验光中相辅相成避免误差,是一种好的工作方法。     

三种不同仪器测量角膜曲率的对比观察

目的 :通过角膜曲率计 ,电脑验光仪 ,角膜地形图仪 (计算机辅助的角膜镜摄影 )三种不同仪器测定角膜曲率的对比观察 ,了解三种不同仪器的性能和优缺点 ,为临床适用仪器提供参考。方法 :选取来我院检查的屈光不正患者 ,年龄 13～ 40岁 ,平均年龄 2 0 5岁 ,66人 ,13 0眼 ,验配前用三种不同仪器测量角膜曲率 ,每人每种仪器测量三次 ,记录角膜曲率的最大值、最小值、角膜散光度数、散光轴位。结果 :结果显示三种仪器所测的角膜曲率的最大值、最小值 ,散光度数和平均角膜曲率值 ,都没有显著性差异 (P >0 0 5 ) ,三种仪器所测的散光轴位差 ,也没有显著性差异。结论 :本实验研究结果提示 ,角膜曲率计、电脑验光仪、角膜地形图仪检测中央角膜曲率的精确率相似。但各有优缺点 ,曲率计较简单 ,便宜、易普及 ,但较主观 ;电脑验光仪可同时测定眼的总屈光状态及晶体散光 ,可大量快速普查人群 ;角膜地形图仪较客观反映全角膜的平、陡地形情况 ,数据精密 ,图形直观 ,但价格昂贵 ,不易普及。     

角膜地形图和角膜曲率计测量散光的研究

目的探讨角膜地形图和角膜曲率计对屈光手术前、后角膜散光的应用价值。方法采用计算机辅助的角膜地形图、角膜曲率计及散瞳验光三种测量散光的方法,对屈光不正患者３６０只眼进行检查,同时对准分子激光角膜切削术（ｐｈｏｔｏｒｅｆｒａｃｔｉｖｅｋｅｒａｔｅｃｔｏｍｙ,ＰＲＫ）后７２只眼和准分子激光原位角膜磨镶术（ｅｘｃｉｍｅｒｌａｓｅｒｉｎｓｉｔｕｋｅｒａｔｏｍｉｌｅｕｓｉｓ,ＬＡＳＩＫ）后９５只眼的角膜散光用角膜地形图和角膜曲率计进行测量并比较。结果术前三组测量方法在散光轴位方面差异无显著性（Ｐ＞０．０５）。在散光度数上,角膜地形图△ＳｉｍＫ和角膜曲率计△Ｋ间差异无显著性（Ｐ＞０．０５）;而散瞳验光组与另两组间差异有显著性（Ｐ＜０．０１）。ＰＲＫ和ＬＡＳＩＫ术后△ＳｉｍＫ与△Ｋ值间差异有显著性（Ｐ＜０．０１）。结论角膜曲率计与角膜地形图对术前角膜散光测量具有相似的临床价值,角膜地形图图形与参数△ＳｉｍＫ值有关。但术后角膜地形图△ＳｉｍＫ测量的角膜散光较为准确     

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。     

角膜地形图与散瞳验光散光差异分析

目的观察角膜地形图仪与散瞳验光测得的散光差异。方法以138眼（74例）近视眼为研究对象，角膜地形图仪记录角膜地形图形态、角膜屈光度、角膜散光度；散瞳后应用全自动电脑验光仪结合带状光检影及试镜．确定球镜度数、柱镜度数和轴位。所有数据用SigmaSTAT软件包进行统计学配对t检验。结果二组总的平均散光度，散瞳组为－1．21±0．9D，角膜地形图组为－1．37±0．63D，统计有显著性差异（P＜0．01）；总平均散光轴位：散瞳验光组为100．14°±76．4°，角膜地形图组为96．80°±78．0°，统计无显著性差异（P＞0．05）。结论　角膜地形图仪和散瞳验光记录的散光度有差异性，轴位无显著性差异，在设计屈光性手术时有指导意义。     

LASIK前后角膜地形图与散瞳验光测量结果的比较分析

目的 观察激光原位角膜磨镶术(laser in situ keratomileusis,LASIK)前后角膜地形图仪与散瞳验光测量结果的差异.方法 以我院行LASIK的患者103例(200眼)为研究对象,进行回顾性分析,测量LASIK术前、术后6个月的散光状态,以角膜地形图仪记录角膜地形图形态、角膜屈光度、角膜散光度;散瞳后应用全自动电脑验光仪结合带状光检影及试镜,确定球镜度数、柱镜度数和轴位.所有数据用SAS 6 12分析软件进行统计学分析.结果 术前散瞳验光测得散光度为(-0.71±0.42)D,角膜地形图测得散光度为(-0 86±0.54)D,2种方法测得散光度有显著统计学差异(t=-5 10,P<0 01);散瞳验光测得散光轴位为(95.09±64.83)°,角膜地形图测得散光轴位为(93.72±71.92)°,2种方法测得散光轴位比较差异无统计学意义(t=-0.72,P>0.05).术后3个月、6个月散瞳验光测得散光度为平均(-0.54±0.38)D、(-0.43±0.33)D,角膜地形图测得散光度分别为平均(-0 51±1.94)D、(-0.42±1.92)D,2种方法测得散光度比较差异无统计学意义(r=-0.11、-0.07,P>0.05),且术后3个月与6个月比较差异无统计学意义(t=0.15,P>0 05);散瞳验光测得散光轴位分别为(75.11±51.17)°、(76.25±51 22)°,角膜地形图测得散光轴位为(76.08±54 96)°、(76 39±55.58)°,2种方法测得散光轴位差异有统计学意义(r=0.78、0.70,P<0.01),且术后3个月与6个月比较差异无统计学意义(t=0.43,P>0.05).结论 LASIK术前角膜地形图仪和散瞳验光记录的散光度有差异性,轴位无显著性差异;LASIK术后角膜形态改变,眼部参数之间的关系也发生改变,角膜地形图仪和散瞳验光记录的散光度无统计学意义,轴位有统计学意义.术后3个月与6个月测量结果证明,LASIK在矫正散光上有较高的精确性,在设计屈光性手术时有指导意义.     

角膜地形图检查在低龄儿童散光检影验光中的应用

目的 通过比较在低龄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285例(554只眼)复性远视散光眼进行检查并比较.结果 两种方法在检查散光轴方面差异无统计学意义(P>0.05),而在检查散光度数方面差异有统计学意义(P<0.05).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的轴向确定提供重要的参考依据,患眼的总合散光仍以睫状肌麻痹后检影、插片接受的度数和散光作为标准,角膜地形图检查在提高低龄儿童散瞳检影验光速度和散光轴向准确度有一定作用.     

不同仪器测量角膜曲率计算人工晶体屈光度的可行性分析

目的探讨角膜曲率计、电脑验光曲率仪和角膜地形图在人工晶体屈光度计算中应用的可行性。方法应用三种仪器测量55只眼的角膜曲率,分别计算人工晶体度数,并对角膜水平轴屈光度、垂直轴屈光度、轴位以及人工晶体屈光度进行统计学分析。结果三种仪器测得的角膜水平轴屈光度(P=0.52)、垂直轴屈光度(P=0.314)和人工晶体屈光度(P=0.152)无显著差异;而轴位测量结果有显著差异(P=0.000)。结论三种角膜曲率测量仪器均可以应用于人工晶体屈光度的计算中,且数据可靠;如果植入的人工晶体与散光轴位有关,则推荐使用自动化角膜曲率计。     

三种仪器测量角膜曲率的准确性比较

目的比较手动角膜曲率计、电脑自动验光仪、角膜地形图仪三种仪器测量角膜曲率结果的准确性,指导白内障术前测量应用。方法仪器应用对照研究。对2014年12月至2015年4月在武清区人民医院眼科应用三种仪器分别测量拟实施白内障超声乳化及人工晶状体植入术的患者140例（140只眼）的最大、最小及平均角膜屈光力,应用电脑自动验光仪和角膜地形图仪测量角膜散光值及散光轴位,使用SPSS20．0软件对所测参数进行统计学分析比较。结果三种仪器测得的最大、最小及平均角膜屈光力对比差异无统计学意义（P〉0．05）,电脑自动验光仪和角膜地形图仪测得的角膜散光值对比差异无统计学意义（P〉0．05）,散光轴位对比差异有统计学意义（P〈0．05）。结论三种仪器测量角膜曲率的准确性较好,均适用于白内障术前测量。     

290只近视眼角膜地形图检查与散瞳检影验光检查的结果分析

目的分析比较角膜地形图与散瞳检影两种方法所测得的散光及与近视度数的关系。方法采用角膜地形图对290只准备行LASIK手术的近视眼进行检查,同时采用散瞳检影法检查记录近视度数及散光并对两种方法所得数据进行比较分析。结果两种方法在散光轴向上无显著性差异(P＞0．5)；而在散光度数方面有非常显著差异(P＜0．01)。角膜地形图检查及检影法所测得的散光度数均与屈光度增高成正比。结论角膜地形图能快速而准确地提供角膜的屈光状态指标；全眼散光仍应以散瞳检影后患眼接受的度数和散光轴作为标准；散光度数均与屈光度增高成正比。     

VERION数字导航系统测量角膜曲率和散光的可重复性及其与iTrace、Lenstar LS900、手动角膜曲率计检测结果的一致性研究

目的 分析VERION数字导航系统测量角膜曲率和散光的可重复性及其与iTrace、Lenstar LS900、手动角膜曲率计检测结果的一致性.方法 对62名年龄相关性白内障患者分别用上述四种仪器进行角膜生物测量,记录并分析陡峭轴角膜曲率(steep keratometry,Ks)、平坦轴角膜曲率(flat keratometry,Kf)、散光幅度、散光轴位、矢量参数J0和J45.分析VERION测量的可重复性,并比较VERION与其他三种仪器测量结果的一致性.结果 用组内相关系数(intraclass correlation coefficient,ICC)和克隆巴赫系数(Cronbach's alpha,α)分别对Ks、Kf、散光幅度、散光轴位、J0以及J45做出分析,结果均大于0.9(均为P＜0.001),提示VERION测量角膜曲率及散光的可重复性极好.VERION测量的Ks、散光幅度均高于iTrace(均为P＜0.05),其余指标的差异无统计学意义(均为P＞0.05).Bland-Altman分析显示J0、J45及散光轴位的95％ LOA分别为(-0.31 ～0.35)D、(-0.25～0.31)D、-13.5°～12.3°.二者测量的散光轴位差小于10°者占总体的77％ (48/62),在合并角膜散光大于1D的患者中占91％ (42/46).VERION与Lenstar LS900测量结果仅J45差异有统计学意义(P＜0.05),其余指标差异无统计学意义(均为P＞0.05).Bland-Altman分析发现J0、J45及散光轴位的95％ LOA分别为(-0.25 ～0.31)D、(-0.27 ～0.36)D、-13.5°～11.0°.二者测量的散光轴位差小于10°者占总体的85％(53/62),在合并角膜散光大于1D的患者中占93％(43/46).VERION与手动角膜曲率计检测的Kf、散光幅度差异有统计学意义(均为P＜0.05),其余指标差异无统计学意义(均为P＞0.05).Bland-Altman分析显示J0、J45及散光轴位的95％ LOA分别为(-0.38 ～0.35)D、(-0.41 ～0.42)D、-12.6° ～16.4°.二者测量的散光轴位差小于10°者占总体的81％ (50/62),在合并角膜散光大于1D的患者中占91％(42/46).结论 VERION在测量角膜曲率及散光方面具有良好的可重复性.其与iTrace、Lenstar LS900和手动角膜曲率计在角膜曲率、散光幅度的测量方面一致性较好,但对散光轴位的测量差别较大.     

Refraction and keratometry in 40 week old premature (corrected age) and term infants

AIM: To compare refraction and keratometry readings between premature and term babies at 40 weeks' postconceptional age (PCA), and the possible effect of birth weight (BW) and gestational age (GA) on ocular parameters. METHODS: 33 preterm babies hospitalised in the neonatal unit between January and March 2002 were matched with 33 term babies born within the same period and hospitalised in the same unit. The preterm group underwent funduscopy at 4-5 weeks after delivery. Ophthalmic examination at 40 weeks' PCA included cycloplegic retinoscopy, funduscopy, and keratometric measurements. Mean and standard deviation of refraction, astigmatic power (plus cylinder), axis of astigmatism, and keratometric reading were calculated and compared between groups and correlated with BW and GA in the premature babies. RESULTS: Retinopathy of prematurity (ROP) stage 1 or 2 was noted in 88% of the premature babies on the first funduscopy examination, but only in 36% by the corrected age of 40 weeks. Statistically significant between groups differences were found for cycloplegic refraction (p = 0.02 for both eyes) and keratometry (p = 0.001 for both eyes). GA and BW had no impact on the refractive and keratometric findings in the preterm babies. CONCLUSIONS: Babies with mild ROP at the corrected age of 40 weeks have mild hypermetropia compared to the moderate hypermetropia found in term babies (a difference of 50%), and they have higher and steeper keratometric values. The greater corneal curvature may contribute to the development of myopia. Ophthalmologists and parents need to be aware of the possibility of visual dysfunction already very early in life even in relatively older premature infants.     

国人近视人群角膜前表面散光与眼球散光的定量分析

目的:研究国人近视人群角膜前表面散光与眼球散光的关系,为眼屈光手术设计提供参考。方法:连续性资料358眼。采用日本TOMEY公司的TMS-4角膜地形图仪进行角膜前表面地形图检查,获取角膜前表面散光度数及轴向;用日本TOPCON公司的RM8000自动电脑验光仪进行散瞳验光,获取眼球散光度数和轴向。结果:眼球散光与角膜前表面散光的比值为0.811±0.665;眼球散光<0.50D者150眼,散光度数差异、散光轴向差异均有统计学意义;散光度数、散光轴向均正相关;0.50D≤眼球散光<1.00D者122眼,散光度数差异有统计学意义;轴向差异无统计学意义;散光度数无相关性,散光轴向正相关;眼球散光≥1.00D者86眼,散光度数差异无统计学意义;散光轴向差异有统计学意义;散光度数、散光轴向均正相关。结论:角膜后表面及晶状体对角膜前表面散光有一定的补偿作用;角膜前表面散光与眼球散光正相关,散光度数越高,相关程度越高;角膜屈光手术根据眼球散光进行手术设计可能较好,屈光性晶状体置换术及白内障手术可根据角膜前表面散光确定手术切口位置。     

儿童散光检测的比较分析

报告７０例（１４０只眼）儿童散光检测的情况。检查方法包括检影验光、电脑验光和角膜曲率计测量，分别得出眼散光（ｅｙｅ＇ｓａｓｔｉｇｍａｔｉｓｍ，ＥＡｓ）和角膜散光（ｋｅｒａｔｉｃａｓｔｉｇｍａｔｉｓｍ，ＫＡｓ）的数据。结果表明，三种方法检测的散光度及散光轴有很好的一致性；眼散光和角膜散光的关系式为ＥＡｓ＝０．９４ＫＡｓ－０．１３，与以往的研究结果一致。我们建议：为了使儿童散光检查准确可靠，有必要采用角膜曲率检查作为验光的辅助方法。     

The repeatability of measurement of the ocular components.

Studies of the ocular components of refraction typically neglect issues of repeatability of measurement methods or analyze method comparison/repeatability data inappropriately using correlation. The authors have examined the repeatability of refractive error measures (retinoscopy, subjective refraction, and Canon R-1 autorefraction, noncycloplegic and cycloplegic), axial dimension measures (Allergan-Humphrey A-scan ultrasound), and corneoscopy (keratometry and KERA photokeratoscopy), and the agreement between different refractive error and corneal measurement methods on 40 pre-presbyopic normal adults. The authors plotted the difference versus the mean of two different measurement occasions (repeatability), or two different methods (agreement), to determine the bias (mean of the differences relative to zero) and 95% limits of agreement of each technique. The most reliable measure of refractive error was autorefraction with cycloplegia, with 95% limits of agreement of +/- 0.32 diopters. Cycloplegic autorefraction had no statistically significant bias compared to cycloplegic subjective refraction. Cycloplegic retinoscopy was the least reliable refractive error measure, with repeat measures on two separate occasions extending over 95% limits of agreement of +/- 0.95 D. Anterior chamber depth was reliable to +/- 0.29 mm, lens thickness to +/- 0.20 mm, and vitreous chamber depth to +/- 0.37 mm. Corneal curvature measures show keratometry to be more reliable (to +/- 0.87 D) than photokeratoscopy (+/- 2.02 D) with a statistically significant bias (paired t-test, P less than 0.0001) of 0.57 D flatter for photokeratoscopy.     

Screening for refractive errors in children: accuracy of the hand held refractor Retinomax to screen for astigmatism

AIMS: To assess the reliability of the hand held automated refractor Retinomax in measuring astigmatism in non-cycloplegic conditions. To assess the accuracy of Retinomax in diagnosing abnormal astigmatism in non-cycloplegic refractive screening of children between 9 and 36 months. METHODS: Among 1205 children undergoing a non-cycloplegic refractive screening with Retinomax, 299 (25%) had repeated non-cycloplegic measurements, 302 (25%) were refracted under cycloplegia using the same refractor, and 88 (7%) using retinoscopy or an automated on table refractor. The reproducibility of non-cycloplegic cylinder measurement was assessed by comparing the cylindrical power and axis values in the 299 repeated measurements without cycloplegia. The influence of the quick mode on cylinder measurement was analysed by comparing the cylinder and axis value in 93 repeated measurements without cycloplegia where normal mode was used in one measurement and quick mode in the other. Predictive values of the refractive screening were calculated for three different thresholds of manifest astigmatism (> or = 1.5, > or = 1.75, and > or = 2 D) considering as a true positive case an astigmatism > or = 2 D under cycloplegic condition (measured by retinoscopy, on table, or hand held refractor). RESULTS: The 95% limits of agreement between two repeated manifest cylinder measurements with Retinomax attained levels slightly less than plus or minus 1 D. The 95% limits of agreement for the axis were plus or minus 46 degrees. The comparison of non-cycloplegic measurements in the quick and normal mode showed no significant difference and 95% limits of agreement plus or minus 0.75 D. The mean difference between non-cycloplegic and cycloplegic cylinder values measured by Retinomax reached 0.17 D and was statistically significant. Manifest thresholds of > or = 1.5 D, > or = 1.75 D, > or = 2 D cylinder value diagnosed 2 D of astigmatism under cyclplegia respectively with 71-84%, 59-80%, 51-54% of sensitivity (right eye-left eye) and 90-92%, 95%, 98% of specificity. CONCLUSION: Without cycloplegia, Retinomax is able to measure cylinder power with the same reproducibility as cycloplegic retinoscopy. No significant difference was found in the cylinder values obtained with the quick and the normal modes. Therefore, the quick mode of measurement is recommended as it is more feasible in children. No difference, which is significant from a screening point of view, exists between the non-cycloplegic and the cycloplegic cylinder value (< 0.25 D). Retinomax diagnoses abnormal astigmatism (> or = 2 D) in a non-cycloplegic refractive screening at preschool ages with 51-84% sensitivity rates and 98-90% specificity rates, depending on the chosen threshold of manifest astigmatism. If 2 D of manifest astigmatism is chosen as a positive test, the positive predictive value of the screening reaches 81-84% and the negative predictive value 91-90% (right eye-left eye).     

Paired opposite clear corneal incisions to correct preexisting astigmatism in cataract patients

PURPOSE: To evaluate the astigmatic correcting effect of paired opposite clear corneal incisions on steep axis in cataract patients. SETTING: Sligo General Hospital, Sligo, Ireland. METHODS: Fifteen eyes of 14 cataract patients with a mean age of 78.4 years +/- 6.38 (SD) (range 69 to 90 years) were recruited for the study. Inclusion criterion was topographic astigmatism of more than 2 diopters (D) in the cataractous eye. Preoperative refraction, autokeratometry, and topography were performed. The steep axis was marked before sub-Tenon's anesthesia was given. Paired 3-step self-sealing opposite clear corneal incisions were made 1 mm anterior to limbus on the steep axis with a 3.2 mm keratome. One incision was used for standard phacoemulsification, and the other was left unused for astigmatic correction. All the patients had day-case surgery. The first follow-up was at 1 month. Postoperative topography, keratometry, and refraction were performed on all patients. RESULTS: Mean preoperative and postoperative topographic corneal astigmatism were 3.26 +/- 1.03 D (range 2.30 to 5.80 D) and 2.02 +/- 1.04 D (range 0.20 to 4.00 D), respectively. Mean astigmatic correction was 1.23 +/- 0.49 D (range 0.30 to 2.20 D). Mean surgically induced astigmatism by vector analysis was 2.10 +/- 0.79 D (range 0.80 to 3.36 D). There were no incision-related complications. CONCLUSION: Paired opposite clear corneal incisions on the steep axis is a useful way to correct astigmatism in cataract patients, requiring no extra skill or instrumentation.     

Autorefractometry after laser in situ keratomileusis

PURPOSE: To correlate cycloplegic subjective refraction with cycloplegic autorefractometry in eyes that have had laser in situ keratomileusis (LASIK). SETTING: Vlemma Eye Institute, Athens, Greece. METHODS: Subjective refraction and autorefractometry under cycloplegia were performed in 73 eyes of 46 patients 1, 6, and 12 months after LASIK to correct myopia or myopic astigmatism. The preoperative subjective refraction and autorefractometry under cycloplegia in the same eyes served as controls. RESULTS: A statistically significant difference between subjective refraction and autorefraction was found in the sphere and cylinder at all postoperative times. No statistically significant difference was found in the axis. There was no statistically significant difference in the control eyes. CONCLUSIONS: Automated refractometry in eyes that had had LASIK was reliable in the axis only. Retreatments after LASIK should always be based on subjective refraction.