中央角膜厚度对3种眼压计眼压测量值的影响

目的比较分析不同中央角膜厚度(central corneal thickness,CCT)下Icare回弹式眼压计、Goldmann压平式眼压计(Goldmann applanation tonometer,GAT)和动态轮廓眼压计(dynamic contour tonometry,DCT)的眼压测量结果,探讨CCT对3种眼压计测量值的影响。方法 对78例患者152眼分别用Icare、GAT、DCT3种眼压计进行眼压测量,并进行CCT的测量,对比不同CCT下3种眼压计的测量结果,分析眼压测量值与CCT的关系。结果 在全部受测者中Icare、GAT、DCT测得的眼压均值分别为(19.16±5.03)mmHg(1 kPa=7.5 mmHg)、(18.41±4.52)mmHg和(17.23±3.69)mmHg,三者之间有显著差异(F=7.256,P=0.001)。Icare和GAT的眼压测量值均与CCT显著相关(r=0.341,P<0.001;r=0.333,P<0.001),CCT每改变10μm,Icare的眼压值改变0.47 mmHg,GAT的眼压值改变0.41 mmHg;而DCT的眼压测量值与CCT无显著相关(r=0.032,P=0.699)。结论 Icare、GAT的眼压测量值均明显受CCT的影响,而Icare受CCT影响的程度较GAT的稍大,DCT的眼压测量值基本不受CCT的影响。     

Icare回弹式眼压计与Goldmann压平眼压计眼压测量结果的比较

背景Icare回弹式眼压计作为一种新式眼压计,有必要对它的临床应用价值进行评估。目的通过比较分析Icare回弹式眼压计和Goldmann压平眼压计（GAT）的眼压测量结果,探讨Icare的临床价值。方法可疑青光眼、青光眼、屈光不正及部分健康体检者78例共152眼同时接受Icare、GAT眼压测量,受检眼先行Icare测量,然后再进行GAT测量,2次测量间隔3～5min。对比分析两种眼压计的测量结果。结果使用Icare和GAT测得的眼压均值分别为（19．16±5．03）mmHg和（18．41±4．52）mmHg,96眼（63．2％）两者的眼压差值≤1mmHg,二者的测量值差异虽有统计学意义,但二者的变化呈明显正相关（r=0．940,P〈0．01）。当Icare眼压测量值〈16mmHg时,Icare的眼压测量值低于GAT,而当Icare眼压测量值≥16mmHg时恰好相反;CCT偏薄、正常以及偏厚的情况下,Icare的眼压测量值均高于GAT的眼压测量值。Icare、GAT的眼压测量值和CCT间呈正相关（r=0．341,P〈0．01;r=0．333,P〈0．01）。结论与GAT眼压计比较,Icare回弹式眼压计易操作,测量结果可靠,临床实用性更强。     

PASCAL动态轮廓眼压计临床应用的初步报告

目的:验证动态轮廓眼压计(DCT)的临床性能。方法:对81例143眼青光眼及可疑病例青光眼患者用DCT测量眼内压(IOP);132眼同时用Goldmann压平眼压计(GAT)测量眼压,部分病例同时用NIDEKUP-1000型角膜测厚仪测量中央角膜厚度(CCT)。GAT与DCT测量结果采用配对t检验,GAT、DCT测量值与CCT的关系及DCT测量值与眼脉动振幅(OPA)的相关关系采用Spearman双变量相关分析。结果:①DCT和GAT测得的眼压均数分别为(18.6±3.9)mmHg和(17.4±4.1)mmHg;DCT测得的眼压值高于GAT,其差值均数为(1.1±2.3)mmHg;两种眼压计测得的眼压值呈正相关(r=0.83,P<0.01)。②116眼同时完成了DCT眼压测量及CCT测量,两者相关系数r=0.03,P=0.77;113眼同时完成了GAT眼压测量及CCT测量,两者相关系数r=0.28,P=0.003。③143眼同时记录了DCT眼压值和眼脉动振幅(OPA),其均数分别为(18.6±3.9)mmHg和(2.6±1.1)mmHg,两者的相关系数r=0.32,P<0.01。结论:以上结果初步证实:①DCT眼压计测量值与GAT眼压测量值高度相关,但DCT测量值略高于GAT测量值,提示DCT可用于临床诊断。②DCT测量值与CCT不相关,GAT测量值与CCT显著相关,提示DCT在青光眼诊断中有独特优势。③DCT测量的OPA与IOP值显著相关,相关的机制及临床意义有待探讨。     

iCare回弹式眼压计与Goldmann压平眼压计测量结果的比较

目的对比iCare回弹式眼压计（RBT）与Goldmann压平眼压计（GAT）测量眼压的一致性,评价RBT测量眼压的准确性及安全性。方法研究为诊断性试验评价。分别用2种眼压计测量角膜正常的患者52例104眼,其中男28例,女24例;年龄19～76岁,以GAT眼压值作为基准分为5组：≤10mmHg、11～20mmHg、21～30mmHg、31～40mmHg、≥41mmHg组。评估2种测量方法的眼压值差值及其与眼压的关系。对RBT眼压值随GAT眼压值变化的关系进行评价。结果 RBT测得的眼压读数为（17.20±9.13）mmHg,GAT测得的眼压读数为（17.13±8.94）mmHg,二者差异无统计学意义（t=0.260,P=0.795）。60.58%的患者2种方法测得的眼压差值在1mmHg以内。5个组中,GAT眼压与RBT眼压的绝对差值随着眼压读数的增高而加大,最大值在≥41mmHg组,二者的最大绝对差值〈4mmHg。RBT眼压读数随着GAT眼压读数的改变而变化,二者的变化呈现良好的相关性（r=0.917,P〈0.01）,但与GAT测量法比较,RBT测得的眼压值均稍高。当GAT眼压值〉21mmHg时,RBT测量的敏感度和特异度分别为95.5%和98.8%。RBT测量后25%的患者主诉有异物感和眼干。结论 iCareRBT测量眼压具有良好的耐受性和安全性,与GAT测量眼压具有较好的相关性,适用于临床。     

动态轮廓眼压计在正常人群中的应用及其影响因素分析

目的评价动态轮廓眼压计（DCT）与Goldmann压平眼压计（GAT）测量值之间的关系,寻找DCT眼压测量值的影响因素;分析DCT所测眼压脉动振幅（OPA）与DCT眼压值、中央角膜厚度（CCT）、角膜屈光力（CCV）、眼轴长度（AL）、前房深度（ACD）、收缩压（SBP）、舒张压（DBP）和心率（HR）的关系。方法分别测量正常人60例60眼的DCT眼压、GAT眼压、CCT、CCV、AL、ACD以及HR、SBP、DBP等指标,比较GAT、DCT2种眼压计测量的相关性及DCT测量值的影响因素。结果 DCT与GAT所测眼压平均值分别为（16.04±2.57）mmHg和（14.20±2.93）mmHg。DCT眼压值较GAT眼压值高,差异有统计学意义（t=6.454,P〈0.01）。DCT眼压值与GAT眼压值呈正相关（r=0.684,P〈0.01）。DCT眼压值与CCT不相关（r=0.212,P=0.105）,GAT眼压值与CCT呈正相关（r=0.291,P=0.024）。60例正常人的OPA均值为（2.50±0.89）mmHg,OPA与年龄、DCT眼压值、CCT、SBP、DBP、HR均不相关（P〉0.05）,与CCV呈正相关（r=0.343,P=0.007）。结论在正常人群中DCT眼压值与GAT眼压值有较好的相关性,DCT的眼压测量值不受CCT、CCV等因素的影响。DCT眼压值、CCT、SBP、DBP、HR等对OPA无明显影响。     

国产回弹式眼压计临床应用对比分析

目的 探讨国产回弹式眼压计临床应用的可靠性、稳定性及对特殊病例测量的优越性.方法 分别使用国产SW-500 SUOER回弹式眼压计、ICARE回弹式眼压计及非接触眼压计(NCT)测量眼科门诊就诊124例患者(124只眼)眼压,并对三者测量结果的相关性进行对比分析.结果 SUOER、ICARE、NCT三种眼压计测量的均值分别为:(16.82±4.46) mm Hg、(16.90±5.50) mm Hg、(16.36±5.16) mm Hg,SUOER与ICARE测量结果相比较差异无统计学意义(P=0.67),NCT与其他两种眼压计相比差异均有统计学意义.三种眼压计测量结果彼此之间具有良好的相关性分别为0.917(NCT-ICARE)、0.927 (NCT-SUOER)、0.944 (ICARE-SUOER).不同眼压区间三种测量值在中眼压组中两两之间的差值较小,在低眼压组与高眼压组中差值较大.不同操作者使用SUOER回弹式眼压计测量结果差异无统计学意义.SUOER回弹式眼压计所需检查时间平均为6.12 s,小于NCT平均测量时间10.37秒,77％的被检查者认为其舒适度优于NCT.结论 国产SUOER回弹式眼压计与ICARE回弹式眼压计一样能方便准确舒适地应用于各种临床患者,尤其对于测量婴幼儿等不能固视、配合不良及瘫痪不能坐位测量的患者有一定的优越性.     

ICARE回弹式眼压计与NCT眼压计测量结果的比较

目的:讨论ICARE回弹式眼压计的临床性能。方法:对78例156眼同时用ICARE回弹式眼压计和NCT眼压计进行眼压测量,对比分析两种眼压计的测量结果及两者的相关情况;观察ICARE眼压计对特殊病例测量的结果。结果:ICARE眼压计和NCT眼压计测得的眼压均值分别为16.55±8.54mmHg和16.81±7.35mmHg,两者无显著差别。两种眼压计测量值显著相关,相关系数为0.964。ICARE眼压计可较好地完成角膜病变和无固视能力等病例的眼压测量。结论:ICARE眼压计可以在临床上运用,尤其适用于其它眼压计测量困难的病例。     

国产回弹式眼压计的临床评价

目的 通过比较国产回弹式眼压计(rebounder tonometer,RBT)与Goldmann压平式眼压计(Goldmann applanation tonometer,GAT)的差别来评价RBT测量的准确性,通过计算测量者间和测量者内的差异来评价其精确性,探讨其临床应用价值.方法 选择2009年6月至12月在北京同仁医院眼压监测室接受昼夜眼压曲线测量的可疑青光眼患者69例138眼.其中,男40例,女29例,年龄(40.0±22.4)岁.所有患者均按RBT、GAT的顺序分别由两名检查者完成眼压测量,每种眼压计的测量均重复3次.分别记录并计算平均数作为该种眼压计的测量结果.测量者一、二需在5 min内完成眼压的测量.比较两位测量者间的差值评价RBT的精确性,比较两种眼压计测量结果间的差值评价RBT的准确性.并分析眼压高低及中央角膜厚度对RBT准确性的影响.结果 RBT和GAT所测右眼的眼压值分别为(20.0±5.1)mmHg(1 kPa=7.5 mmHg)和(20.4±5.2)mmHg,差值为(0.4±2.5)mmHg,二者比较,差异无统计学意义(t=1.211,P=0.230).RBT和GAT所测左眼的眼压值分别为(20.5±4.7)mmHg和(20.4±4.8)mmHg,差值为(0.1±2.0)mmHg,二者比较,差异也无统计学意义(t=-0.318,P=0.751).两种眼压计所测眼压之间均有明显相关.左、右两眼r值分别为0.878(P=0.000)和0.912(P=0.000).RBT不同测量者间的差异不具有显著性,测量者间相关系数在左、右眼分别为0.956和0.939,有较好的一致性.RBT测量者内相关系数在0.978～0.991,与GAT的结果接近.低眼压患者RBT的值大于GAT,高眼压患者RBT值小于GAT,正常眼压时两种仪器测得眼压的差值最小;中央角膜厚度较薄时RBT值偏低,中央角膜厚度较厚时RBT值偏高.结论 RBT的准确性和精确性可以满足临床工作的需求.     

国产回弹式眼压计在儿童眼压测量中的应用

目的：观察国产回弹式眼压计在儿童眼压监测中的应用。方法：对本院眼视光门诊就诊的108例儿童进行两眼眼压测量,年龄大于13岁的儿童回弹式眼压计（ rebound tonometer,RBT）测量完成后左眼进行Goldmann压平式眼压计（ Goldmann applanation tonometry,GAT）眼压测量。 结果：两眼均顺利完成RBT眼压测量的儿童100例,成功率92.6%（100/108）,其中13岁以上24例。24例左眼RBT和GAT眼压平均值分别为16.0±3.0 mmHg （1 kPa=7.5mmHg）和15.7±2.8mmHg,两者差异无统计学意义（P〉0.05）,两者具有良好的相关性（r=0.849,P〈0.05）。100例儿童的左右眼眼压均呈正态分布,平均值分别为16.0±2.8mmHg和16.2±2.6mmHg,两者差异无统计学意义（P〉0.05）,两者具有良好的相关性（r=0.863,P〈0.05）。 结论：国产回弹式眼压计在儿童眼压测量中简单易操作,无需麻醉,准确性较高,能够较好满足临床儿童眼压测量的需求。     

他氟前列素对原发性开角型青光眼和高眼压症患者24小时眼压的影响

目的：通过测量24 h眼压评估他氟前列素对原发性开角型青光眼（POAG）和高眼压症（OHT）患者的 临床疗效。方法：系列病例研究。收集2018年1月至2019年3月在沈阳爱尔眼视光医院初次诊断的 POAG和OHT患者22例（43眼）,由医师对所有患者进行Icare HOME眼压计操作培训及认证,认证合 格后使用Goldmann压平眼压计（GAT）测量眼压3次,然后由患者使用Icare HOME眼压计自我监测 用药前24 h眼压,之后每天2100给予他氟前列素点眼1次,1个月后患者自我监测用药后24 h眼压。 采用单因素方差分析和Bland-Altman分析比较医师使用GAT和患者使用Icare HOME眼压计测量眼 压的一致性。采用配对t检验分析患者使用他氟前列素治疗前后各个时间点的眼压值、24 h眼压均值、 峰值、谷值和波动值的变化。结果：医师使用GAT和患者使用Icare HOME眼压计测量眼压的平均值 分别为（18.2±3.7）mmHg（1 mmHg=0.133 kPa）和（17.4±4.2）mmHg,差异无统计学意义（F=0.837, P=0.363）。Bland-Altman分析证明医师使用GAT和患者使用Icare HOME眼压计测量眼压具有良好 的一致性。使用他氟前列素治疗1个月后,所有评估时间点的眼压均降低（均P<0.05）,不同时间点 眼压降低的范围为1.8～5.5 mmHg。用药前24 h眼压均值、峰值、谷值、波动值分别为（19.4±5.0）、 （25.0±5.8）、（14.1±4.5）、（10.9±3.8）mmHg,用药后分别降低至（15.6±4.2）、（20.4±4.5）、（11.3±3.6）、 （9.2±2.9）mmHg,差异均有统计学意义（t=9.450、9.636、5.939、3.137,均P<0.05）。结论：对于初 次诊断的POAG和OHT患者,他氟前列素可明显降低24 h中所有评估时间点的眼压。     

Assessment of IcareONE rebound tonometer for self‐measuring intraocular pressure

Purpose: To evaluate the precision of the IcareONE rebound tonometer, which was developed for self‐measuring intraocular pressure (IOP) and to compare IcareONE measurement with Goldmann applanation tonometry (GAT). Methods: Twenty‐four healthy eyes and 81 glaucomatous eyes were enrolled. IOP measurements (three times per session) with IcareONE were made in a random order by an ophthalmologist (Icare(O)) and by the subject (Icare(S)). Intraclass correlation coefficients (CCs), kappa values and mean values of IOP were compared among the two types of Icare recordings and GAT. Bland–Altman analysis was used to assess agreement between methods. Multiple regression analysis was performed to identify the subject factors that influenced the discordant measurements between IcareONE and GAT. Results: The mean value of Icare(O) and Icare(S) measurements was 13.5 ± 5.2 and 13.5 ± 5.4 mmHg, respectively, neither of which was significantly different from GAT (13.8 ± 4.4). The intrarater CC of Icare(O) and Icare(S) was 0.968 and 0.885, respectively. The intermethod CC and weighted kappa between Icare(O) and Icare(S) were 0.907 and 0.684, respectively. All pairwise correlations between the two types of IOP measurement showed coefficients of determination >0.8. Bland–Altman analysis did not show any proportional biases. Multiple regression analysis revealed that the differences between GAT and Icare(O) or Icare(S) were positively correlated with central corneal thickness (CCT) and negatively correlated with age. Conclusions: Intraocular pressure measurements with IcareONE by a physician and by the subject showed excellent agreement with GAT measurements; IcareONE measurements between a physician and the subject had high intrarater reliability, and good agreement thicker CCT led IcareONE measurement to overestimate IOP, while higher age caused it to underestimate IOP compared with GAT.     

Agreement and repeatability of Icare ic100 tonometer

Purpose:To find the agreement and repeatability of Icare ic100 tonometer.Methods:We included 150 subjects above the age of 18 years for this cross-sectional, multicenter study with intraocular pressure (IOP) ≥7 mmHg. After the initial ophthalmic examination, two masked examiners took five IOP measurements using three different instruments; Icare ic100, Icare TA01i, and Goldmann applanation tonometer (GAT) in only one eye of the participants. Comparison of agreement of IOP using different instruments was quantified with intraclass correlation coefficient (ICC) using the two-way random effects models of absolute agreement and Cronbach''s alpha. The test-retest variability of the instruments was assessed by deriving repeatability coefficient (RC) and coefficient of variation (CV).Results:Agreement between the tonometers across the different IOP groups had no statistically significant difference in their mean IOP. Icare ic100 was found to have good reliability across all IOP groups (ICC value >0.78) when compared with Icare TA01i. In comparison with GAT, Icare ic100 showed good reliability across all IOP groups (ICC >0.87) except >16 to <23 mmHg group where it showed moderate reliability (ICC = 0.52). Icare ic100 showed good repeatability with RC and CV of 2.67 and 4.89, respectively.Conclusion:Icare ic100 rebound tonometer can measure IOP with relatively small measurement error and can provide a reliable and repeatable reading in comparison with GAT across a wide pressure range without hampering corneal health.     

Comparison of the new rebound tonometer with Goldmann applanation tonometer in a clinical setting

Purpose: To evaluate the clinical usefulness of a new rebound tonometer, Icare^® PRO (Icare PRO), by comparison with Goldmann applanation tonometry (GAT) in a study on patients with glaucoma. Methods: One hundred and seventy‐two eyes of 86 subjects were enrolled in this study. All of the subjects were examined with an autorefractometer, Icare PRO, slit‐lamp biomicroscope, GAT, ultrasound A‐scan and pachymeter. Three intraocular pressure (IOP) measurements were obtained by Icare PRO and GAT. The intraobserver reliabilities were established by calculating the intraclass correlation coefficients. The Bland–Altman plot was used to compare the Icare PRO and GAT. Results: There was a good correlation between the IOP measurement by GAT and that by Icare PRO (r = 0.6995, p < 0.001). The intraclass correlation coefficients of Icare PRO and GAT were 0.778 and 0.955, respectively. The IOP differences between Icare PRO and GAT (mean: 1.92 mmHg; SD: 3.29 mmHg; 95% limit of agreement: ?4.52 to 8.37 mmHg) did not vary over the wide range of central corneal thickness (p = 0.498), age (p = 0.248), axial length (p = 0.277) or spherical equivalent (p = 0.075). Conclusions: Although IOP with Icare PRO was higher than that with GAT, especially at lower GAT IOP value, Icare PRO was found to be a reliable method and showed a good correlation with GAT. The IOP difference between Icare PRO and GAT was not affected by the central corneal thickness, age, axial length or spherical equivalent. Icare PRO can be expected not only to be a good screening tool but also to be a good substitute for GAT.     

可疑青光眼患者清晨起床前后的体位变化和日常活动对眼压的影响

目的：观察可疑青光眼患者清晨起床前后的体位变化和日常活动对眼压的影响。 方法：使用Icare回弹式眼压计对51例100眼可疑青光眼患者进行清晨起床前后的卧、坐位和日常活动前后的眼压测量,对比分析卧、坐位眼压和日常活动前后的眼压测量结果。 结果：起床前卧、坐位测量的眼压均值分别为19.14±5.51和17.12±4.53mmHg,两者差别显著。清晨日常活动前后测量的眼压均值分别为17.12±4.53和14.44±3.90mmHg,两者有显著差别。 结论：起床前后的体位变化和日常活动可以导致显著的眼压变化。     

Repeatability and accuracy of applanation resonance tonometry in healthy subjects and patients with glaucoma

Purpose: To evaluate the repeatability and accuracy of the applanation resonance tonometer (ART) used in the automatic servo‐controlled version, and to evaluate the influence of central corneal thickness (CCT) on the ART intraocular pressure (IOP) measurements. Methods: This prospective, randomized, single‐centre study included one eye of 153 subjects (35 healthy volunteers and 118 patients with glaucoma). All participants underwent ultrasonic CCT measurement, followed by IOP evaluation with Goldmann applanation tonometer (GAT) and ART in random order. A single operator measured the IOP with each tonometer three times. Intra‐examiner variability was evaluated using the coefficient of variation (CoV), intraclass correlation coefficient (ICC) and test–retest differences. Intermethod agreement was assessed using the Bland–Altman method. Linear regression analysis was used to evaluate the relationship between IOP measurements and CCT. Results: The mean IOP was 17.7 ± 4.4 mmHg with GAT and 20.6 ± 5.3 mmHg with ART (p < 0.001). CoV and ICC were, respectively, 5 ± 3% and 0.99 for GAT, and 8 ± 4% and 0.96 for ART (intermethods differences, p = 0.001). The ART test–retest differences significantly increased with increasing mean IOP (p = 0.003). The mean IOP difference (ART minus GAT) was 3.0 ± 4.0 mmHg, which increased with increasing mean IOP (p < 0.001). Both GAT IOP and ART IOP readings were significantly directly related to the CCT values (p = 0.03 and p = 0.004, respectively; intermethods difference, p = 0.32). Conclusions: The ART intra‐examiner repeatability was excellent, although significantly lower than that of GAT, and decreased at higher IOP levels. ART significantly overestimated GAT IOP measurements, especially at higher IOP range. Both GAT and ART appeared similarly influenced by CCT value.     

双眼之间PASCAL动态轮廓眼压计眼压测量值的比较及OPA与眼压的关系

目的分析双眼之间PASCAL动态轮廓眼压计(dynamic contour tonometer,DCT)眼压(intraocular pressure,IOP)测量值的差异及眼脉动振幅(ocular pulse amplitude,OPA)与IOP的关系,探讨双眼DCT IOP差异形成的可能影响因素。方法 2007年4月至2008年2月就诊于我院的非青光眼患者147例(293眼)分别用DCT与GAT进行双眼IOP测量,同时记录OPA值,两种仪器的测量顺序随机确定,同一种眼压计均先测右眼,再测左眼。双眼之间IOP值及OPA的比较采用配对t检验,OPA值与DCT所测IOP值的相关性采用Spearman双变量相关分析。结果 129例(258眼)完成DCT测量,其左眼、右眼IOP值分别为(17.3±3.1)mmHg(1kPa=7.5mmHg)、(17.6±3.1)mmHg,差值(0.4±1.7)mmHg;左右眼OPA值分别为(2.2±0.9)mmHg、(2.4±0.9)mmHg,左眼均低于右眼,双眼之间DCT所测IOP值及OPA值差异均具有显著统计学意义(t=2.399,P=0.018;t=3.49,P=0.001);147例GAT测量中排除5例(9眼)双眼IOP差值大于4mmHg,其余284眼其左眼、右眼GAT所测IOP值分别为(16.2±3.5)mmHg、(16.1±3.4)mmHg,二者之间差异无统计学意义(t=-1.45,P=0.149)。PASCAL DCT所测得的左右眼OPA值与IOP值均呈弱相关(r=0.262,P=0.002;r=0.259,P=0.002)。结论 DCT所测得的IOP值及OPA值其右眼均高于左眼,且OPA与IOP呈弱相关关系,而GAT无这种表现。     

Effect of corneal thickness on intraocular pressure measurements with the Pascal dynamic contour,Canon TX‐10 non‐contact and Goldmann applanation tonometers in healthy subjects

Purpose: To investigate the effects of central corneal thickness (CCT) on intraocular pressure (IOP) measurements of the Pascal dynamic contour tonometry (DCT), Canon TX‐10 non‐contact tonometry (NCT) and Goldmann applanation tonometry measurements (GAT) in healthy subjects. Methods: IOP values of 135 eyes with normal corneas of 135 healthy volunteers were determined by DCT, NCT and by GAT. The CCT was measured using an ultrasonic pachymeter after all IOP determinations had been made. Results: When DCT measurements were compared (IOP = 17.52 ± 2.0 mmHg) with NCT measurements (IOP = 16.54 ± 2.77 mmHg) and GAT measurements (IOP = 15.07 ± 2.35 mmHg), DCT measurements were significantly higher than NCT and GAT (p < 0.001). There was a significant correlation between CCT with both NCT (r = 0.260, p = 0.003) and GAT measurements (r = 0.257, p = 0.005). There was a weak correlation that was not statistically significant between CCT and DCT (r = 0.160, p = 0.079). Conclusion: The IOP measurements with DCT seem to be less dependent on CCT. NCT appears to be more affected by variation in CCT than GAT.     

Effects of corneal thickness on intraocular pressure measured with three different tonometers

Purpose: To compare intraocular pressure (IOP) measured by a Goldmann applanation tonometer (GAT), a noncontact tonometer (NCT), and a portable noncontact tonometer (PNCT) in eyes of healthy volunteers, and to determine if a significant correlation exists between the IOP and the central corneal thickness (CCT). Methods: A total of 144 healthy participants were randomly assigned to one of two groups; in the first group, IOP was measured first with the NCT and then with the GAT. In the second group, IOP was measured first with the PNCT and then with the GAT. Subsequently, the CCT of all subjects was measured with an ultrasonic pachymeter. Results: The IOPs determined by the GAT and NCT and were strongly correlated, as were those determined by the GAT and PNCT, in both groups. However, a Bland-Altman plot showed that the correlations between the GAT and NCT and between the GAT and the PNCT measurements were not significant. With all three instruments, the IOP readings varied with the CCT. The mean IOPs obtained with the GAT increased by 0.23 mmHg with each 10-μm increase in CCT (0.23 mmHg/10 μm). The comparable value for the NCT was 0.29 mmHg/10 μm, and that for the PNCT was 0.31 mmHg/10 μm. Conclusions: For measurements of IOP in normal eyes, the GAT is the tonometer least affected by the CCT, compared with the PNCT and NCT. A PNCT is more likely to be affected by variations in CCT than the GAT.