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。     

LASIK术后角膜生物力学变化与眼压测量值的相关性

目的 观察LASIK术后角膜生物力学参数和眼压测量值的变化及角膜生物力学变化与眼压的相关性。设计 前瞻性病例系列。研究对象 哈尔滨医科大学附属第一医院2014年1-12月LASIK手术患者81例（162眼）。方法 应用非接触眼压计（non-contact tonometer,NCT）分别在术前及术后3个月测量眼压。同时应用眼反应分析仪（ocular response analyzer,ORA）测量角膜滞后量（corneal hysteresis,CH）、角膜阻力因子（corneal resistance factor, CRF）、模拟Goldmann 眼压（Goldmann intraocular pressure,IOPg）和角膜补偿眼压（corneal-compensated intraocular pressure,IOPcc）。比较手术前后各参数的变化并分析术后角膜生物力学参数变化与眼压测量值的相关性。 主要指标 手术前后NCT、IOPcc、IOPg、CH、CRF。 结果 LASIK术后3个月CH、CRF、IOPcc、IOPg、NCT测量值与术前比较均显著降低,术后IOPcc与IOPg和NCT之间比较差异均有统计学意义（P<0.05）;△CH、△CRF与△IOPcc、△IOPcc- IOPg和△IOPcc-△NCT均成负相关,△CH、△CRF与△IOPg和△NCT均成正相关（P<0.05）;CH和CRF的减少量与眼压测量值下降具有相关性（P<0.05）。结论 LASIK术后角膜生物力学参数和眼压测量值均较术前显著降低,眼压测量值下降与CH和CRF的减少量具有相关性,说明眼压下降的程度可能受角膜生物力学特性的影响。     

中央角膜厚度对Goldmann眼压计与非接触式眼压计测量值的影响

目的探讨中央角膜厚度（CCT）对Goldmann眼压计与非接触式眼压计（NCT）眼压测量值的影响。方法分别用Goldmann眼压计与NCT测量83例（83只眼）正常人的眼压,采用光学相干断层扫描仪（OCT）测量CCT。采用配对T检验比较Goldmann眼压计与NCT眼压计眼压测量值的差异,采用线性相关分析方法分析两种眼压计眼压测量值之间的相关关系,并分析CCT对两种眼压计眼压测量值的影响。结果Goldmann眼压计测得的眼压平均值为（13.46±2.93）mmHg,NCT测得的平均值为（12.29±3.47）mmHg,两者之间差异有显著性（t=5.831,P〈0.001）;两种眼压计眼压测量值呈正相关（r=0.852,P〈0.001）。Goldmann眼压计眼压测量值和NCT眼压测量值均与CCT呈正相关,r值分别为0.424（P〈0.001）和0.568（P〈0.001）。Goldmann眼压计眼压测量值与NCT眼压测量值的差值与CCT呈负相关（r=-0.402,P〈0.001）。去除CCT因素影响后,两种眼压计眼压测量值的残差差异无显著性（t=-0.272,P=0.787）。结论Goldmann眼压计与NCT眼压计眼压测量值均受CCT的影响，CCT对NCT眼压测量值的影响更大；两种眼压计眼压测量值的差异可能来源于个体CCT的差异。     

中央角膜厚度、角膜曲率对Goldmann压平眼压计和非接触眼压计测量结果的影响

目的 探讨中央角膜厚度和角膜曲率对Goldmann压平眼压计(GAT)和非接触眼压计(NCT)测量结果 的影响.方法 比较性研究.选择120例门诊患者作为研究对象.应用超声角膜测厚仪测量患者中央角膜厚度,采用多功能验光仪测量角膜曲率,应用GAT和NCT测量受检者双眼眼压.应用SPSS 12.0统计学软件进行数据处理.采用直线回归法比较两种眼压计的测量结果 ,采用多重线性同归法分析中央角膜厚度、角膜曲率与两种眼压计所测眼压值的关系,应用Bland-Altman法比较NCT和GAT两种方法 对眼压测最结果 的影响.结果 GAT与NCT测量的平均眼压值分别为(18.4±4.0)mm Hg(1 mm Hg=0.133 kPa)和(17.0±4.6)mm Hg,差异有统计学意义(r=0.835,P=0.000).GAT和NCT测量的眼压值均受中央角膜厚度和角膜曲率的影响.中央角膜厚度每增加1μm,GAT测量眼压值增加0.039 mm Hg,而NCT测量眼压值增加0.064 mm Hg.角膜曲率半径每增加1 mm,GAT测最眼压值减少2.648 mm Hg,NCT测量眼压值减少3.190 nun Hg.中央角膜厚度对NCT测量眼压值的影响较其对于GAT测量眼压值的影响大.随着眼压的升高,NCT测最眼压值呈现出由低于GAT测量值到高于GAT测量值的逐渐变化趋势.结论 中央角膜厚度和角膜曲率均会影响NCT和GAT测量眼压值,而且中央角膜厚度对NCT测量眼压值的影响较其对GAT测量眼压值的影响大.     

角膜生物参数对青光眼患者眼压测量影响的研究

目的:探讨角膜生物参数对青光眼患者眼压测量的影响。方法:对80例121眼青光眼患者进行眼反应分析仪(ocular response analyzer,ORA)与Goldmann压平眼压计(Goldmann applanation tonometer,GAT)测量,并用先进的OrbscanⅡ眼前节分析系统测量中央角膜厚度(central corneal thickness,CCT)。结果:平均矫正眼压(IOPcc)值17.41±5.62mmHg;平均GAT值15.76±6.06mmHg;IOPcc与角膜滞后性(cornealhysteresis,CH)有相关性(P=0.000;r=-0.236);IOPcc与GAT显著相关(P=0.000;r=0.857);IOPcc与CCT无相关性。结论:对已经诊断的青光眼患者,平均IOPcc值高于平均GAT值;随着CH的降低,IOPcc值有升高的趋势;且IOPcc值不受CCT值的影响。     

青年女性生理周期期间角膜生物力学性能和眼压的节律性变化

目的探讨中国青年女性生理周期期间角膜生物力学性能和眼压的节律性变化以及两者之间的关系。方法前瞻性研究。41例健康青年女性分别在月经周期初期、排卵期和月经周期末期用眼反应分析仪（ORA）对角膜补偿眼压（IOPcc）、可重复模拟Goldmman眼压（IOPg）、角膜滞后量（CH）和角膜阻力因子（CRF）进行测量。采用Pentacam对CCT进行测量。采用重复测量方差分析法分析测量参数在不同时间点的变化以及Pearson相关进行相关性分析。结果在女性生理周期的不同阶段,CCT、CH和CRF存在波动,但差异无统计学意义,在月经周期末期IOPcc和IOPg均较初期显著下降（P<0.01）。△IOPg与△CRF呈低度正相关（r=0.356,P<0.05）,与△CH呈低度负相关（r=-0.336,P<0.05）,△IOPcc则与△CH呈中度负相关（r=-0.702,P<0.01）,与△CRF不相关（r=-0.069,P>0.05）。△CRF、△CH、△IOPg和△IOPcc均与△CCT无明显相关性（│r│均<0.3,P均>0.05）。结论在女性生理周期期间,角膜生物力学性能无明显变化但眼压在月经周期末期发生了显著下降。IOPg的变化与CH、CRF低度相关,而IOPcc则与CH中度相关,与CRF不相关。角膜生物力学性能可能是眼压的影响因素之一。     

新型非接触式眼压分析仪ORA与Goldmann压平眼压计的比较

目的比较新型非接触式眼压分析仪ORA与Goldmann压平式眼压计测量眼压的差异,以评价ORA眼压测量仪在临床眼压测量中的应用价值。方法本院门诊127例237眼分别由专人进行非接触眼压测量仪ORA与Goldmann压平式眼压计测量,并同时用超声角膜测厚仪测量角膜厚度。结果127例病人237眼,Goldmann压平眼压值和ORA直接测量结果（IOPG）分别为（17.94±6.50）mmHg和（18.88±7.93）mmHg,两者比较差异有显著统计学意义（P=0.000）;正常人群平均角膜厚度为（546.19±36.34）μm,经角膜厚度-眼压公式校正IOPG平均值为17.42±3.92mmHg,ORA经自带软件处理后的眼压值（IOPcc）平均为（17.50±4.38）mmHg,两者比较差异无统计学意义（P=0.681）,IOPG校正前两者比较差异有统计学意义（P=0.024）。结论新型非接触式眼压分析仪ORA的直接测量值与Goldmann压平眼压计的测量值相近略高,ORA的测量分析值IOPcc是排除角膜因素影响更接近真实的眼压结果。     

角膜补偿眼压与前房穿刺测量眼内压的比较

目的 比较角膜补偿眼压(IOPcc)与前房穿刺测量眼压(direct intracameral IOP,IOPintra),探讨角膜生物特性对眼压测量的影响.方法 双肓前瞻性研究.拟行超声乳化手术患者73例(73只眼),随机选择1只眼.超声测厚仪测量中央角膜厚度(CCT),ORA测量IOPcc和角膜生物属性:角膜滞后性(cornealhysteresis,CH).角膜阻力因子(corneal resistance factor,CRF).应用IOD眼压测量装置行前房穿刺测量IOPintra.结果 IOPintra为(15.48±4.64)mmHg,IOPcc为(16.63±3.68)mmHg;IOPcc高出IOPintra(1.15±4.12)mmHg(P=0.019);IOPcc和IOPintra与CH、CRF相关,IOPcc,IOPintra及两者的差异与CCT不相关;IOPcc与IOPintra的差异与cH相关(r=-0.283 P=0.015).结论 IOPcc读数比IOPintra高1.15mmHg,其差异受CH影响.角膜生物属性对眼压测量的影响需慎重考虑.     

角膜厚度对两种眼压测量方法的影响

目的　比较非接触眼压计 (non -contacttonometer ,NCT)和Goldmann压平眼压计测量眼压的差异 ,并分别探讨中央角膜厚度 (centralcornealthickniss ,CCT)对这两种测量方法的影响。方法　对 1 0 8例拟接受PRK或LASIK手术的患者行CCT ,NCT和Goldmann压平计眼压测量。结果NCT和Goldmann压平眼压计测得的眼压均值具有显著性差异 (F =89 .70 4 4,P <0 . 0 1 )。CCT与NCT和Goldmann压平眼压计测量值呈正相关 ,相关系数分别是r =0. 4 96 0 (t =8 .356 3,P <0 .0 0 1 )和r =0 . 2 1 1 3(t =3. 1 6 2 3,P <0 .0 0 1 )。结论　NCT和Goldmann压平眼压计测量眼压值有差异 ,NCT测量值大于Goldmann压平眼压计 ,CCT对NCT的影响大于Goldmann压平眼压计。     

动态轮廓眼压计与非接触式眼压计的比较

目的探讨中央角膜厚度和角膜曲率对轮廓动态眼压计以及非接触式眼压计眼压测量结果的影响。方法接受准分子激光原位角膜磨镶术(LASIK)的近视患者27例(54只眼),分别于术前和术后第4周使用非接触式眼压计(NCT)和动态轮廓眼压计(DCT)进行眼压测量。多元线性相关分析研究NCT、DCT测量值和角膜曲率及角膜中央厚度(CCT)之间的相关性。结果LASIK术后NCT测量值降低,而DCT测量值和术前比较差异则无统计学意义。角膜曲率、CCT和NCT读数呈线性相关,而与DCT读数无关。结论DCT测量眼压不受角膜曲率和中央角膜厚度影响,因此更适合于正常眼以及曾经接受角膜屈光手术眼的眼压测量。     

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.     

Comparison of IOP measurements between ORA and GAT in normal Chinese.

PURPOSE: To compare intraocular pressure (IOP) obtained from the ocular response analyzer (ORA) and Goldmann applanation tonometer (GAT) on a group of normal Chinese. METHODS: One hundred twenty-five normal subjects were recruited, with one eye randomly selected for this study. Each eye was measured first with the noncontact tonometer ORA, followed by the GAT and ultrasound pachometry, in a randomized order. Four readings were obtained from the ORA, and three measurements were taken with the GAT. The mean was used for analysis. The ORA provided a Goldmann-correlated IOP (IOPg) and a corneal-compensated IOP (IOPcc). Three central corneal thickness (CCT) values were measured using an ultrasound pachometer, and the mean was used for analysis. RESULTS: IOP obtained from the ORA was similar to that from the GAT (IOPg minus GAT: mean difference = 0.33 mm Hg, 95% limits of agreement = 4.55 to -4.44 mm Hg; IOPcc minus GAT: mean difference = 0.24 mm Hg, 95% limits of agreement = 4.83 to -5.07 mm Hg). CCT was positively associated with corneal hysteresis (CH) (r2 = 0.30, p < 0.01), corneal resistance factor (r2 = 0.38, p < 0.01), GAT (r2 = 0.09, p < 0.01) and IOPg (r2 = 0.16, p < 0.01). IOPcc was not associated with CCT (r2 = 0.01, p = 0.33). CONCLUSIONS: Both IOPg and IOPcc have good agreement with GAT on normal subjects. The influence of CCT on IOPcc was insignificant.     

Der Einfluss von kornealer Hysterese und kornealem Resistenzfaktor auf die Messung des intraokularen Drucks

BACKGROUND: The influence of central corneal thickness (CCT) on the measurement of intraocular pressure (IOP) has been discussed extensively in recent years. The problem, however, has not been solved so far. In addition to CCT there are probably further biomechanical properties that play a role in IOP measurement. We wanted to find out whether these properties are related to Goldmann applanation tonometry (GAT), noncontact tonometry (NCT), or CCT. MATERIAL AND METHODS: Biomechanical properties of the cornea such as corneal hysteresis (CH) and corneal resistance factor (CRF) can be measured with the Ocular Response Analyzer (ORA, Reichert Ophthalmic Instruments, Depew, NY, USA). Furthermore, a corneal compensated IOP (IOPcc) is given. We examined 156 normal eyes of 80 patients who did not show corneal pathology nor glaucoma. In each eye GAT, NCT, and ORA data as well as CCT were measured. Data were statistically analyzed with respect to agreement and the influence of CH and CRF on IOP measurement. RESULTS: In our patients the following average values were calculated: GAT 14.8+/-3.0 mmHg, NCT 16.4+/-3.9 mmHg, IOPcc 16.2+/-4.1 mmHg, CH 10.6+/-2.3 mmHg, CRF 10.9+/-2.4 mmHg, and CCT 557+/-36 microm. IOPcc was not related to CCT in normal eyes and the only IOP value related to CH (p<0.01). CRF, however, was related to GAT and NCT values (p<0.01). DISCUSSION: In our group of normal eyes IOPcc, i.e., the value that is adjusted by measurement of viscoelastic properties of the cornea, in contrast to GAT and NCT does not depend on central corneal thickness. Corneal hysteresis and corneal resistance factor provide further information about biomechanical properties of the cornea beyond central corneal thickness.     

角膜补偿眼压（IOPcc）和5种眼压校正公式所得校正眼压的一致性及IOPcc、模拟Goldmann眼压与眼球各参数的相关性分析

目的　比较眼反应分析仪测得的角膜补偿眼压（corneal-compensated intraocular pressure,IOPcc）和Sirius眼前节分析系统内置的5种眼压校正公式所得校正眼压的一致性,分析IOPcc、模拟Goldmann眼压（Goldmann-correlated intraocular pressure,IOPg）与眼球各参数的相关性。方法　选取2016年11月至2017年3月在我院眼科中心行近视激光治疗的患者90例90眼,年龄18～37（24.47±5.57）岁。应用Sirius眼前节分析系统对所有患者按常规方法测量3次,选择最佳测量结果作为各参数最终结果。应用眼反应分析仪测量患者的角膜生物力学参数。根据眼反应分析仪测量的IOPg输入Sirius眼前节分析系统内置的5种眼压校正公式进行计算,得到的校正眼压分别记录为Dresdner校正眼压、Ehlers校正眼压、Kohlhaas校正眼压、Orssengo/Pye校正眼压和Shah校正眼压。将所得的5种校正眼压和非接触性眼压计眼压与眼反应分析仪测得的IOPcc进行一致性分析。对IOPcc、IOPg与角膜滞后量、角膜阻力因子、眼球各参数进行相关分析。结果　Kohlhaas校正眼压和IOPcc比较差异有统计学意义（P<0.05）。Dresdner校正眼压、Orssengo/Pye校正眼压与IOPcc的一致性较好,95%一致性界限分别为 （-2.09～2.55）mmHg、（-2.38～2.37）mmHg;其中Dresdner校正眼压与IOPcc的95%一致性界限宽度最窄。IOPcc与角膜滞后量、角膜阻力因子以及眼球各参数均无相关性,而IOPg与角膜阻力因子、中央角膜厚度、角膜体积呈正相关关系 （均为P<0.05）。结论　Dresdner校正眼压、Orssengo/Pye校正眼压与IOPcc的一致性较好;眼球大部分参数对IOPcc影响小。     

Comparation of the new rebound tonometer IOPen and the Goldmann tonometer, and their relationship to corneal properties

Purpose

To compare the intraocular pressures (IOPs) obtained with the IOPen rebound tonometer, Goldmann applanation tonometer (GAT) and the ocular response analyzer (ORA) and investigate the effects of corneal biomechanical properties on IOPen measurements.

Methods

A total of 198 normal eyes were included in this cross-sectional and randomized study. Three measurements were taken using IOPen. Agreement between tonometers was calculated using the Bland and Altman limits of agreement (LoA) analysis.

Results

The median IOPen IOP was 3 mm Hg below the GAT (P<0.001), 3 mm Hg below the ORA IOP similar to Goldmann (IOPg), and 3 mm Hg below the ORA IOP corrected using corneal parameters (IOPcc)(P<0.01). The LoA width between the IOPen and GAT IOPs varied between 13.92 (mean IOPen IOP) and 15.99 mm Hg (third IOPen measurement). The central corneal thickness (CCT) was unrelated to IOPen measurements (P>0.05). Corneal hysteresis (CH) and corneal rigidity factor (CRF) were correlated with IOPen and GAT.

Conclusions

IOPen underestimated the IOP compared with GAT and ORA. The effect of measurement quality or measurement order on IOPen was low. CCT did not affect the IOPen, but the CH and CRF did. The LoA width between the IOPen and GAT IOPs was higher than between the ORA IOPg or ORA IOPcc and GAT IOPs.     

Corneal biomechanical properties in normal‐tension glaucoma

Purpose: To investigate the intraocular pressure (IOP) and corneal biomechanical properties of normal and normal‐tension glaucoma (NTG) eyes. Methods: This study included 83 normal and 83 NTG eyes. We measured corneal‐compensated IOP (IOPcc), Goldmann‐correlated IOP (IOPg), corneal resistance factor (CRF), corneal hysteresis (CH) and central corneal thickness (CCT) three times each for normal and NTG eyes using an Ocular Response Analyzer (ORA). Results: No significant difference in CCT was seen between normal eyes (541.4 ± 26.8 μm) and NTG eyes (535.4 ± 24.9 μm; p = 0.16). IOPcc was significantly higher in NTG eyes (16.1 ± 2.6 mmHg) than in normal eyes (15.1 ± 2.9 mmHg; p = 0.01), while IOPg was significantly lower in NTG eyes (14.1 ± 2.7 mmHg) than in normal eyes (15.1 ± 3.0 mmHg; p = 0.04). CRF and CH were significantly lower in NTG eyes (CRF, 8.9 ± 1.5 mmHg; CH, 9.2 ± 1.3 mmHg) than in normal eyes (CRF, 10.6 ± 1.4 mmHg; CH, 10.8 ± 1.3 mmHg; p < 0.0001 each). Conclusion: IOPcc was significantly higher in NTG eyes than in normal eyes. The ORA may be useful for distinguishing between the IOPcc of NTG eyes with normal IOP and that of normal eyes. In addition, the ORA enables CRF and CH to be measured in vivo, and weakness of the lamina cribrosa may be clinically inferred from the fact that CRF and CH were reduced in NTG eyes in our study. Low CRF and CH may be clues to the pathology of NTG.     

Effect of pathological myopia on biomechanical properties: a study by ocular response analyzer

AIM: To evaluate the ocular response analyzer (ORA) measurements of patients with pathological myopia in comparison with those of emmetropic control subjects, and to investigate the correlation between these ORA measurements and spherical equivalent (SE). METHODS: Measurements of 53 eyes of 53 subjects with pathological myopia (SE>-6.00 D) were compared with those of 60 eyes of 60 emmetropic controls. Corneal hysteresis (CH), corneal resistance factor (CRF), noncontact tonometer intraocular pressure (IOPg), and corneal-compensated IOP (IOPcc) were obtained for each subject. The refractive error value was determined as SE via a cycloplegic refraction test. RESULTS: The mean age was 54.1±18.9y (ranging from 5 to 88) in the pathological myopic group and 56.2±19.0y (ranging from 6 to 89) in the control group. There were no significant differences between the groups concerning age and sex. CH and CRF were significantly lower in the pathological myopic group than in the control group (P<0.001, P=0.005, respectively). IOPcc and IOPg were significantly higher in the pathological myopic group than in the control group (P<0.001, P=0.009, respectively). There were significantly positive correlations between CH and SE (r=0.565, P<0.001) and between CRF and SE (r=0.364, P=0.007). There were significantly negative correlations between IOPcc and SE (r=-0.432, P=0.001) and between IOPg and SE (r=-0.401, P=0.003). CONCLUSION: The present study displayed that pathological myopia affected biomechanical properties measured by ORA. The results of corneal biomechanical properties measured by ORA may need to be appreciated by taking refraction into account. Further, pathological myopia might be related with the increased IOP.     

Ocular Response Analyzer in subjects with and without glaucoma.

PURPOSE: The Ocular Response Analyzer (ORA) is a newly introduced tonometer that uniquely measures and then integrates corneal biomechanical data into its intraocular pressure (IOP) estimates in an effort to improve accuracy of IOP assessment. This study was devised to investigate whether ORA-derived IOP and corneal biomechanical variables might be useful in discriminating between subjects with and without primary open-angle glaucoma (GLC). METHODS: All patients seen in the Albuquerque VAMC eye clinic over a 10-week period who demonstrated acceptable ORA signal profiles were retrospectively identified. In subjects classified as normal (NML), ocular hypertension (OH), glaucoma suspect (GS), and GLC, the following variables were compared: age, ethnicity, Goldmann IOP, central corneal thickness (CCT), and ORA-derived data: Goldmann-correlated IOP (IOPg), corneal-compensated IOP (IOPcc), corneal resistance factor (CRF), corneal hysteresis (CH), and difference between IOPcc and IOPg (DIOP; IOPcc - IOPg). RESULTS: Right eyes in 71 NML, 58 OH, 70 GS, and 99 GLC subjects were studied. Using analysis of variance, higher mean age, higher mean DIOP, and lower mean CH were found in the GLC group compared with OH, GS, and NML groups. In multivariate regression analyses, factors that independently discriminated between groups were: age, IOPcc, and DIOP (GLC vs. NML); age and IOPcc (GLC vs. GS); age and CRF (GLC vs. OH). When DIOP was left out of the models, CH replaced DIOP in the GLC vs. NML analysis with nearly equal statistical power. CONCLUSIONS: Our results suggest that ORA-generated parameters may be useful for differentiating subjects with and without GLC. Furthermore, the discriminatory power of each ORA variable seems to depend on the diagnostic groups that are being compared. Finally, our findings also suggest that measured IOP may be significantly underestimated in glaucoma patients compared with non-glaucoma patients.     

Hornhautdickenunabhängige Methoden der Messung des Augeninnendrucks

Introduction

Goldmann applanation tonometry (GAT) has been the gold standard for measuring intraocular pressure (IOP) for about 50 years. However, it depends on central corneal thickness (CCT) and is, therefore, prone to being incorrect. Dynamic contour tonometry (DCT) has recently been introduced to measure IOP independently of CCT; however, DCT is costly and difficult. IOP measurement using the ocular response analyzer (ORA) offers noncontact tonometry with declaration of the corneal-compensated IOP (IOPcc), which takes corneal hysteresis (CH) into account and is supposed to be independent of CCT.

Patients and methods

Using the ORA instrument, IOPcc was determined in 192 glaucoma eyes and 59 nonglaucoma eyes. Subsequently, measurement by DCT and GAT was performed. IOP measurements were compared and analyzed with respect to CCT and CH.

Results

Average values were as follows: IOPcc, 18.38±6.3 mmHg; GAT, 14.69±4.5 mmHg; DCT, 15.17±3.9 mmHg; CH, 9.96±2.5 mmHg; CCT, 552±57 μm. Neither CCT nor CH differed between the two groups. There was a positive correlation between GAT and CCT that did not exist for IOPcc and DCT values. However, IOPcc and DCT differed significantly in Bland–Altman analysis (p<0.01). Furthermore, these two IOP values differed significantly with respect to CH and the level of IOP.

Conclusion

Because IOPcc is not a primarily measured variable but also takes CH into account, a direct comparison of DCT and IOPcc values is not acceptable, and a simple correction factor may not be valid.