Corneal hysteresis measured with the Ocular Response Analyzer® in normal and glaucomatous eyes

Purpose: To identify differences in corneal hysteresis (CH) and central corneal thickness (CCT) between healthy and glaucomatous patients. Methods: Retrospective observational study. One hundred and thirty‐three eyes of 75 healthy and 58 glaucomatous patients were included. CH was measured in each patient using Ocular Response Analyzer. CCT was determined by ultrasonic pachymetry. For each patient, one eye was randomly selected. We used a Student t‐test to search for significant differences between the different groups (p<0.05). Results: In healthy and glaucomatous eyes, mean CH values were 10.46 ± 1.6 and 8.77 ± 1.4 mm Hg, respectively. Mean CCT values were 560.2 ± 36.3 and 535.3 ± 42.7 μm, respectively. CH and CCT were significantly lower in glaucomatous eyes than in normal eyes, (p<0.05). Discussion: In our series, CH was lower in glaucomatous than in normal eyes. The relationship between glaucoma, IOP, and ocular structures may not be confined to the consideration of CCT. A low CH value could be responsible for under‐estimation of IOP. CH could also be a risk factor for glaucoma, independent of IOP. Further studies are needed to support these hypotheses. Conclusion: In our investigation, CCT and CH were significantly lower in glaucomatous eyes than in healthy eyes.     

Comparison of the corneal biomechanical properties with the Ocular Response Analyzer® (ORA) in African and Caucasian normal subjects and patients with glaucoma

Purpose: To compare corneal hysteresis (CH) and corneal resistance factor (CRF) measured with the Ocular Response Analyzer^® tonometer (ORA) between (i) African normals and treated primary open‐angle glaucoma (POAG) patients and (ii) between normals and treated POAG Caucasians. To analyse the correlation of CH and CRF with visual field (VF) defects in the two groups. Methods: This comparative study included 59 African (29 (POAG), 30 normals) and 55 Caucasians (30 POAG and 25 normals) subjects. Goldmann applanation tonometry (GAT) and ORA measurements were performed in a randomized sequence. Visual field was tested with the Swedish interactive threshold algorithms standard strategy of the Humphrey perimeter. Hoddap classification was used to estimate the severity of VF defects. Results: Primary open‐angle glaucoma Africans were younger than POAG Caucasians (p < 0.001). Goldmann applanation tonometry and central corneal thickness (CCT) did not differ significantly between the four subgroups. African normals had lower CH than Caucasian controls (p < 0.001). CH was 9.2 ± 1.1 and 8.3 ± 1.7 mmHg respectively in POAG Caucasians and Africans (p < 0.001). African controls had higher ORA corneal‐compensated intraocular pressure (IOPcc) than Caucasian controls (p < 0.001). Primary open‐angle glaucoma Africans had higher IOPcc values than Caucasian POAGs (p < 0.001). CH and IOPcc were associated with race (p < 0.001) but not with CCT. Based on mean deviation values (MD), POAG Africans had more severe VF defects. CH was correlated with MD (r = 0.442; p = 0.031) and severity of VF defects only in POAG Africans (r = ?0.464; p = 0.013). Conclusions: African normal subjects and POAG patients had an altered CH, which is associated with a significant underestimation of GAT IOP. This may potentially contribute to the earlier development and greater severity of glaucoma damage in Africans compared with Caucasians at diagnosis.     

Variation in corneal hysteresis and central corneal thickness among black,hispanic and white subjects

Purpose: To determine whether differences in corneal hysteresis (CH) and central corneal thickness (CCT) between black, Hispanic and white subjects exist independently of one another. Methods: Retrospective, cross‐sectional data were reviewed for 807 eyes of 410 patients consecutively evaluated for glaucoma. Included patients had open angles, at least one reliable 24‐2 perimetric examination and no evidence of nonglaucomatous vision loss. Patients underwent CH measurement with the ocular response analyzer followed by CCT measurement and full ocular examination. Patients were asked to self‐classify their race or ethnicity. Statistical analyses were performed to identify characteristics that varied between black, Hispanic and white subjects and to explain this variation. Results: Of the 270 patients (511 eyes) included, 84 were black, 96 Hispanic and 90 white. There were no significant differences in diagnosis, sex, age, intraocular pressure or glaucoma severity between races/ethnicities (p ≥ 0.16). Blacks were found to have lower CCT (529.3 μm) and CH (8.7 mmHg) compared to Hispanics (544.7 μm, p = 0.008; 9.4 mmHg, p = 0.007) and whites (549.9 μm, p < 0.001; 9.8 mmHg, p < 0.001). On multivariable analysis, inter‐racial/ethnic differences in CCT were not found to exist independent of CH (p ≥ 0.10), whereas the significant intergroup variation in CH remained after adjustment for CCT and other covariates (p ≤ 0.005). Conclusions: Variation in CCT between races/ethnicities does not exist independent of CH. However, significant intergroup variation in CH is present independent of CCT. This finding suggests that CH may be a preferable measurement to evaluate intergroup differences in corneal properties and their relationship to open‐angle glaucoma.     

波前像差与眼内压、中央角膜厚度的日波动规律及相关性

目的研究正常人全眼像差、角膜前表面像差和眼内压(intraocular pressure,IOP)、中央角膜厚度(centralcorneal thickness,CCT)的日间波动规律、相互关系及影响因素。方法选择20例测试对象(20只右眼),于一天的三个时间点(早:8:00am~8:30am,午:1:00pm~1:30pm,晚:6:00pm~6:30pm)使用Humphrey角膜地形图和Hartmann-Shack原理设计的WASCA波前像差分析仪分别测量角膜前表面像差和全眼像差,在6.0mm分析直径下,取2~4阶12项Zernike系数进行分析。使用Canon非接触式眼内压计和TOMEY角膜测厚仪分别测量IOP及CCT。采用SPSS13.0统计软件对所测数据进行分析。结果IOP、CCT的日波动呈下降趋势,差异有统计学意义。角膜前表面像差日波动差异有统计学意义的为C13,呈增加趋势;全眼像差日波动差异有统计学意义的为C7,呈下降趋势。全眼像差C7与CCT日波动量呈正相关,而角膜前表面像差C13与CCT日波动量无相关性;两者与IOP日波动量均无相关性。结论IOP和CCT的日波动呈下降趋势。角膜前表面像差C1...     

高度近视眼角膜中央厚度与眼压、屈光度和眼轴的关系

目的:探讨眼角膜中央厚度(CCT)与眼压(IOP)、屈光度和眼轴之间的关系。方法:高度近视126例252眼,行CCT、IOP、屈光度和眼轴检查,并对所得数据行方差分析、直线回归分析和Kruskal-Wallis检验。根据角膜中央厚度分4组:1组480μm≤CCT<500μm,12眼;2组500μm≤CCT<550μm,135眼;3组550μm≤CCT<600μm,83眼;4组CCT≥600μm,22眼;计算相对应的眼压值,并行方差分析、直线回归分析。根据近视屈光度不同分为4组,即按等效球镜分为:1组-6.00D≤屈光度<-7.00D,72眼;2组-7.00D≤屈光度<-8.00D,80眼;3组-8.00D≤屈光度<-9.00D,48眼;4组≥-9.00D,52眼。分别计算其相对应的IOP、CCT和眼轴平均值,对获得的数据行方差分析、直线回归分析。根据眼轴不同分为4组,即1组23mm≤眼轴<24.2mm,54眼,2组24.2mm≤眼轴<25.5mm,92眼,3组25.5mm≤眼轴<26.7mm,67眼,4组26.7mm≤眼轴<28mm,39眼。分别计算其相对应的IOP、CCT和屈光度平均值,并行Kruskal-Wallis检验。结果:CCT与IOP呈正相关关系,回归方程为Y=-0.7527352 0.0373008X(CCT为X,IOP为Y),t=8.4044,P=0.00。根据CCT分4组的IOP分别为11.22±1.22,11.96±2.15,13.61±2.38和15.98±3.37mmHg,方差分析F=24.73,P=0.00001,各组间比较除1组与2组间差异无显著性外,余各组间比较差异均有非常显著性(P<0.01)。根据近视屈光度分4组的IOP分别为12.76±2.31,13.10±2.71,12.28±2.90和12.951±2.69mmHg。方差分析F=1.02,P=0.3844>0.05,各组间差异无统计学意义;4组CCT分别为547.4±30.4,547.6±35.6,539.6±29.3和544.6±33.2μm,方差分析F=0.73,P=0.5360>0.05,各组间比较无显著性意义,CCT与近视屈光度之间没有相关性。根据眼轴分组,各组间比较CCT、IOP与眼轴之间在统计学上没有差异,与眼轴的变化没有关系。随眼轴的增长,屈光度逐渐增加。结论:高度近视眼IOP与CCT密切相关,当CCT>550μm时,尤为明显,随CCT增加IOP增加;CCT与屈光度、眼轴之间没有关联;IOP与屈光度之间也没有相关性;当高度近视屈光度大于-7.00D时眼轴显著增长,所以高度近视度数增加眼轴长也增加。     

区域性汉族人近视眼角膜中央厚度临床研究

目的探讨汉族人近视患者角膜厚度的分布特征及其对Goldman眼压计眼压测量的影响。方法分别用超声角膜测厚仪和Goldman眼压计测量1583例近视患者角膜中央厚度(central corneal thickness,CCT)和眼压(intraocularpressure,IOP),并进行统计学分析。结果男性的CCT平均值为(551.19±34.61)μm,大于女性的(545.73±33.59)μm,CCT值与年龄和屈光度呈负相关。IOP随CCT增加而增高,并呈正相关(CCT每增加100μm,IOP将随之增加1.5mmHg)。高眼压症组CCT大于正常眼压组。结论CCT是影响眼压测量的重要因素,检查眼压的同时应该测量CCT。     

正常视力人群眼压和角膜中央厚度的关系

目的:了解正常视力人群(视力≥5.0)眼压和角膜中央厚度之间的关系.方法:分别采用角膜超声厚度计以及非接触式眼压计对视力≥5.0的志愿者54人(108眼,男22名,女32名,年龄27.82±7.78岁)进行角膜中央厚度的测量以及眼压测量.结果:正常视力人群眼压和角膜中央厚度均呈正态分布,眼压为14.63±3.25mmHg,中央角膜厚度为547.15±31.91μm.眼压和角膜中央厚度呈正相关,r=0.441,P＜0.001.线形回归方程为Y=-10.05 0.045X,其中,Y为眼压,X为角膜中央厚度.其R2=0.195,拟合效率较低.结论:国人正常视力人群的眼压和角膜中央厚度均呈正态分布,两者之间呈正相关关系.正常视力(视力≥5.0)人群的角膜中央厚度可以在一定程度上反映眼压的大小,但影响较小.     

近视伴高眼压症的眼压与中央角膜厚度的关系

目的 :探讨近视眼患者中高眼压症的眼压与中央角膜厚度的关系及其临床意义。方法 :用超声角膜测厚仪及非接触眼压计对 14例 2 8眼近视伴高眼压症患者的中央角膜厚度和眼压进行测定 ,并采用SPSS 10 .0作统计分析。结果 :14例 2 8眼的眼压范围为 2 0～ 2 9mmHg,平均 (2 3.88± 2 .2 6 )mmHg ;中央角膜厚度为 5 33～ 6 70 μm ,平均 (5 86 .5 0± 31.91) μm ;屈光度为 - 0 .75～ - 3.5 0D ,平均 - (1.5 0± 0 .6 9)D。应用SPSS(10 .0 )软件进行相关分析 :眼压与厚度经回归分析 ,直线方程式为 :Y(中央角膜厚度 ) =4 4 5 .15 1+5 .92 0X(眼压 ) ;眼压与屈光度的相关系数r =0 .35 5 ,P >0 .0 5。结论 :眼压与中央角膜厚度成正相关 ,与屈光度无相关性。近视眼中高眼压症的眼压升高与中央角膜厚度增加有关 ,提示近视眼伴高眼压症患者的真实眼压可能是正常的 ,只是由于中央角膜厚度的增加而使眼压的测量值升高。检测中央角膜厚度有助于更正确地估计实际的眼压值。     

角膜滞后量在青光眼中的作用

青光眼是全球首位不可逆致盲性眼病,其具体发病机制尚不清楚,但颇受重视的是眼压和房水流出通道等方面。近年,研究人员开始越来越多地关注非压力依赖因素如角膜滞后量(CH)在青光眼中的作用。CH是角膜的生物力学参数,它反映了角膜的黏性阻力,即吸收和分散能量的能力。CH在临床上很容易获得,可作为眼后部组织生物力学特性的替代标志物,如筛板和乳头周围巩膜,这些组织可能与青光眼损伤的易感性有关。有研究提供了CH与青光眼临床相关结果之间的联系的证据。本文综述了CH在青光眼中的作用的最新发现,从CH的测量方法、CH与中央角膜厚度、青光眼性视野进展、视盘损害、视网膜神经纤维层缺失等方面进行了归纳和总结。     

中央角膜厚度对常用眼压计测量值的影响

眼压在青光眼和其他眼科疾病的诊断和疗效评估中起着很重要的作用。已经有不少研究发现,各种眼压计的测量值都受中央角膜厚度的影响。不同的眼压计所受影响不同。本文对中央角膜厚度和不同眼压计测量值的关系进行综述。     

近视眼中央角膜厚度与眼内压的关系探讨

目的探讨近视眼患者中央角膜厚度与眼内压之间关系。方法用超声角膜测厚仪及非接触眼压计对325例（635只眼）近视患者的中央角膜厚度和眼压进行测定,并采用统计学方法处理。结果 325例635只眼的眼压范围为21～30mmHg,平均22.96±3.13mmHg;中央角膜厚度为480～656μm,平均579.35±29.45μm;屈光度为-0.75～-8.50D,平均-5.50±0.58D。近视眼患者角膜厚度不同,其眼压有非常显著性差异（P〈0.01）。近视眼患者的眼压与角膜中央厚度呈正相关（γ=0.538,P〈0.01）。结论近视眼的角膜中央厚度与眼压呈显著正相关。检测中央角膜厚度有助于更正确地估计实际的眼压值。     

Corneal hysteresis in patients with dry eye

Purpose

To measure corneal hysteresis and intraocular pressure (IOP) in patients with dry eye and to compare with normal subjects.

Methods

This cross-sectional study consists of 70 eyes of 40 patients with dry eye (group 1) and 75 eyes of 40 normal subjects (group 2). Eyes were diagnosed as dry eye or normal according to the clinical symptoms, biomicroscopical evaluation, and Schirmer test. Corneal hysteresis (CH), corneal resistance factor (CRF), and cornea-compensated intraocular pressure (IOPcc) were measured by the Ocular Response Analyser (ORA).

Results

Mean CH values were 10.56±0.25 mm Hg and 10.34±0.26 mm Hg, mean CRF values were 10.75±0.28 mm Hg and 10.70±0.28 mm Hg, mean CCT values were 542±3.20 μm and 543±3.89 μm in group 1 and group 2, respectively. There was no statistically significant difference between the groups for these three parameters. IOPcc values measured with ORA were 15.73±0.36 mm Hg in group 1 and 16.60±0.33 mm Hg in group 2, and there was no statistically significant difference between the two groups.

Conclusions

Corneal biomechanical parameters such as CH and CRF are not influenced in dry eye. Also statistical difference was not found between the two groups according to CCT and IOPcc values.     

ORA眼反应分析仪的临床应用价值

眼反应分析仪(reichert ocular response analyzer,ORA)是一种新型非接触喷气式眼压计。它利用一种动态双向压平过程测量眼压,不仅使测得的眼压值真实可靠,免受中央角膜厚度和硬度的影响,而且可得到反应角膜生物力学特性的新指标:角膜滞后量和角膜阻力因素。其操作简单,能自动显示眼压读数及角膜生物力学特性。该仪器精确度高,可重复性好,非接触特性,因此可广泛用于临床监测眼压,尤其适用于已行准分子激光角膜屈光手术后的患者,但仍需进一步明确其对青光眼诊断和治疗的指导作用。     

Elastic hysteresis in human eyes is an age‐dependent value

Background: The elastic hysteresis phenomenon is observed when cyclic loading is applied to a viscoelastic system. The purpose of this study was to quantitatively evaluate elastic hysteresis in living human eyes against an external force. Design: Prospective case series. Participants: Twenty‐four eyes of 24 normal human subjects (mean age: 41.5 ± 10.6 years) were recruited. Methods: A non‐contact tonometry process was recorded with a high‐speed camera. Central corneal thickness, corneal thickness at 4 mm from the centre, corneal curvature and anterior chamber depth were measured. Intraocular pressure was also measured using Goldmann applanation tonometry and dynamic contour tonometer. Main Outcome Measures: Energy loss due to elastic hysteresis was calculated and graphed. Results: The mean central corneal thickness was 552.5 ± 36.1 µm, corneal curvature was 7.84 ± 0.26 mm and anterior chamber depth was 2.83 ± 0.29 mm. The mean Goldmann applanation tonometry‐intraocular pressure was 14.2 ± 2.7 mmHg and dynamic contour tonometer‐intraocular pressure was 16.3 ± 3.5 mmHg. The mean energy loss due to elastic hysteresis was 3.90 × 10⁻⁶ ± 2.49 × 10⁻⁶ Nm. Energy loss due to elastic hysteresis correlated significantly with age (Pearson correlation coefficient = 0.596, P = 0.0016). There were no significant correlations between energy loss due to elastic hysteresis and other measurements. Conclusion: Energy loss due to elastic hysteresis in the eyes of subjects was found to positively correlate with age, independent of anterior eye structure or intraocular pressure. Therefore, it is believed that the viscosity of the eye increases with age.     

Assessment of intraocular pressure measured by Reichert Ocular Response Analyzer, Goldmann Applanation Tonometry, and Dynamic Contour Tonometry in healthy individuals

AIM: To investigate the accuracy of intraocular pressure (IOP) as measured by a Reichert Ocular Response Analyzer (ORA), as well as the relationship between central corneal thickness (CCT) and IOP as measured by ORA, Goldmann applanation tonometry (GAT), and dynamic contour tonometry (DCT). METHODS: A total of 158 healthy individuals (296 eyes) were chosen randomly for measurement of IOP. After CCT was measured using A-ultrasound (A-US), IOP was measured by ORA, GAT, and DCT devices in a randomized order. The IOP values acquired using each of the three tonometries were compared, and the relationship between CCT and IOP values were analyzed separately. Two IOP values, Goldmann-correlated IOP value (IOPg) and corneal-compensated intraocular pressure (IOPcc), were got using ORA. Three groups were defined according to CCT: 1) thin cornea (CCT<520μm); 2) normal-thickness cornea (CCT: 520–580μm); and 3) thick cornea (CCT>580μm) groups. RESULTS: In normal subjects, IOP measurements were 14.95±2.99mmHg with ORA (IOPg), 15.21±2.77mmHg with ORA (IOPcc), 15.22±2.77mmHg with GAT, and 15.49±2.56mmHg with DCT. Mean differences were 0.01±2.29mmHg between IOPcc and GAT (P>0.05) and 0.28±2.20mmHg between IOPcc and DCT (P>0.05). There was a greater correlation between IOPcc and DCT (r=0.946, P=0.000) than that between IOPcc and GAT (r=0.845, P=0.000). DCT had a significant correlation with GAT (r=0.854, P=0.000). GAT was moderately correlated with CCT (r=0.296, P<0.001), while IOPcc showed a weak but significant correlation with CCT (r=?0.155, P=0.007). There was a strong negative correlation between CCT and the difference between IOPcc and GAT(r=-0.803,P=0.000), with every 10μm increase in CCT resulting in an increase in this difference of 0.35mmHg. The thick cornea group (CCT>580μm) showed the least significant correlation between IOPcc and GAT (r=0.859, P=0.000); while the thin cornea group (CCT＜520μm) had the most significant correlation between IOPcc and GAT (r=0.926, P=0.000). The correlated differences between IOPcc and DCT were not significant in any of the three groups (P>0.05). CONCLUSION: Measurement of IOP by ORA has high repeatability and is largely consistent with GAT measurements. Moreover, the ORA measurements are affected only to a small extent by CCT, and are likely to be much closer to the real IOP value than GAT.     

动态轮廓眼压计与Goldmann压平眼压计及非接触眼压计测量眼压的对比研究

目的探讨动态轮廓眼压计(DCT)与Goldmann压平眼压计(GAT)及非接触眼压计(NCT)测量眼压的准确性,并比较三种眼压计测量结果与中央角膜厚度(CCT)的相关性。设计前瞻性、比较性病例系列。研究对象连续选取90例(90眼)10~76岁正常人。方法采用KONAN非接触式角膜内皮镜测量CCT后,对所有入选者单眼以随机顺序采用Pascal型DCT、GAT及Topcon型NCT测量眼压。测量结果两两比较,并将眼压值与CCT进行直线回归分析。主要指标眼压值,Pearson相关系数。结果 90例正常人DCT眼压平均值(17.33±2.71 mm Hg)明显高于GAT(14.27±2.81 mm Hg)(P=0.000)及NCT(14.67±2.93 mm Hg)(P=0.000),平均差异分别为(3.06±2.01)mm Hg和(2.67±2.20)mm Hg;GAT与NCT之间平均差异为(-0.39±2.29)mm Hg(P=0.105)。DCT与GAT眼压值之间相关系数r=0.736(P=0.000);与NCT眼压值之间相关系数r=0.699(P=0.000)。GAT、NCT眼压值与CCT均明显相关(r=0.370,P=0.000;r=0.508,P=0.000);DCT眼压值与CCT无明显相关性(r=0.051,P=0.639)。DCT和GAT的差值与年龄无明显相关性(r=0.064,P=0.052)。结论 DCT测量的眼压值虽高于GAT及NCT,但不受CCT的影响,可能较GAT和NCT测量的眼压值更接近真实值。     

Factors affecting corneal hysteresis in normal eyes

BACKGROUND: To evaluate factors affecting corneal hysteresis (CH) in normal eyes. METHODS: We examined 86 normal eyes of 43 healthy volunteers (age, 39.1 +/- 14.5 years (mean +/- standard deviation); range, 19 to 68 years; gender, 26 men, 60 women; manifest refraction, -2.25 +/- 2.89 diopters (D); range, -9.13 to 3.88 D). We quantitatively assessed the value of CH using an Ocular Response Analyzertrade mark (Reichert Ophthalmic Instruments). We carried out this measurement three times, and the average value was used for statistical analysis. Multiple regression analysis was used to assess the relevant factors of the CH. RESULTS: The mean CH was 10.2 +/- 1.3 mmHg. Explanatory variables relevant to the CH were, in order of magnitude of influence, the central corneal thickness (CCT) (partial regression coefficient B = 0.022, p < 0.0001), and the intraocular pressure (IOP) (B = -0.119, p = 0.04). No significant correlation was seen with other clinical factors such as age, gender, manifest refraction, or mean keratometric readings. CONCLUSIONS: Eyes with thinner CCT and eyes with higher IOP are more predisposed to have lower CH. Refractive surgeons should, from a biomechanical viewpoint, take not only CCT but also IOP into consideration before performing keratorefractive surgery.     

Response of corneal hysteresis and central corneal thickness following clear corneal cataract surgery

Purpose: To evaluate the effect of routine phacoemulsification in corneal viscoelastic properties determined by corneal hysteresis (CH) and central corneal thickness (CCT) and to explore the impact of phaco energy on the above parameters. Methods: Forty‐one eyes of 41 patients undergoing cataract surgery were enrolled in this prospective study. CH and CCT were measured preoperatively, 1 day and 1 week postoperatively. CCT measurement was performed using a non‐contact optical pachymeter followed by ocular response analyzer (ORA) examination. Intraoperatively ultrasound time, average phaco power and effective phaco time (EPT) were recorded. Results: Mean CH was 10.05 ± 1.86 mmHg preoperatively, 8.25 ± 1.85 mmHg 1 day and 9.12 ± 1.37 mmHg 1 week postoperatively (p < 0.001). The mean CCT was 534 ± 37.33 μm preoperatively, 592.22 ± 46.34 μm 1 day and 563.21 ± 49.84 μm 1 week postoperatively (p < 0.001). CCT and CH were statistically significantly correlated preoperatively (p = 0.01, r = 0.396). This correlation was not sustained on the first postoperative day (p = 0.094, r = 0.265) and was re‐established 1 week postoperatively (p = 0.002, r = 0.568). On the first postoperative day, the CCT increase was positively correlated with EPT (p = 0.009, r = 0.404), which was not found between CH change and EPT. Conclusion: Structural corneal alterations following cataract surgery resulted in a statistical change in CH and CCT. These two parameters responded in a different manner that clearly demarcates their different nature. On the first postoperative day, CCT increase was correlated at a statistically significant level with intraoperative EPT. This correlation was not found with CH reduction. Other factors, besides cornea oedema or phacoemulsification energy, could be responsible for this CH modification.     

近视眼角膜中央厚度与眼压和屈光度的关系

目的 :探讨近视眼角膜中央厚度 (centralcornealthickness,CCT)与眼压 (IOP)、屈光度之间关系。方法 :10 0例193只眼行角膜中央厚度、眼压、屈光度、眼轴检查 ,并对所得数据行方差分析、直线回归分析。根据角膜中央厚度分四组 :1组 4 4 5 μm 相似文献