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.     

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。     

PASCAL动态轮廓眼压计与Goldmann压平眼压计在非青光眼人群中眼压测量值的比较及一致性分析

目的探讨在不同的中央角膜厚度(CCT)下PASCAL动态轮廓眼压计(DCT)与Goldmann压平眼压计(GAT)眼压(IOP)测量值的相关性,评价两者测量值的一致性及临床上两种眼压计测量值相互替换的可能性。方法非青光眼病例87例(168只眼)分别用DCT和GAT进行眼压测量,两种仪器的测量顺序随机。同时,用NIDEK UP-1000型角膜测厚仪测量CCT。DCT与GAT眼压测量值的相关性采用Spearson双变量相关分析,Bland-Altman分析法评价两种仪器IOP测量值的一致性。结果 (1)在不同的角膜厚度下DCT与GAT测得的IOP值均显著相关(CCT≤520μm,n=24,r=0.67,P<0.001;520μm580μm,n=44,r=0.61,P<0.001)。(2)DCT眼压测量值与CCT不相关(r=0.14,P=0.08),GAT眼压测量值与CCT显著相关(r=0.59,P<0.001)。(3)Bland-Altman一致性分析显示两种仪器的差值的均值为-0.9mm Hg,一致性界限为(-5.6 mm Hg,3.9 mm Hg)。结论 (1)在不同的角膜厚度下DCT与GAT的眼压测量值均显著相关。(2)DCT眼压测量值与CCT值不相关,GAT眼压测量值与CCT值显著相关。(3)一致性分析显示两者测量值的一致性界限跨度较宽,二者的IOP值不可简单地相互代替。     

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。     

动态轮廓眼压计与非接触眼压计的比较

目的比较动态轮廓眼压计（DCT）与非接触眼压计（NCT）测量眼压的差异,并探讨中央角膜厚度（CCT）对这两种测量方法的影响。方法对75例拟接受近视手术的患者进行角膜厚度测量后,对所有眼分别用DCT和NCT进行眼内压（IOP）的测量,并比较中央角膜厚度与两种眼压计读数的关系。对所有数据进行t检验和相关分析。结果NCT和DCT测得的眼压值具有显著性差异（t=9．2932,P〈0．01）。NCT测量值与CCT呈正相关,相关系数r=0．3482（P〈0．01）。DCT测量值与CCT无相关性,相关系数r=0．0635,P〉0．05）。结论NCT和DCT测量眼压值有差异,DCT测量值大于NCT,CCT对NCT的影响大于DCT。     

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。     

动态轮廓眼压计监测LASIK手术前后眼压变化

目的比较动态轮廓眼压计(DCT)、Goldmann压平式眼压计(GAT)及非接触式眼压计(NCT)测量接受准分子激光原位角膜磨镶术(LASIK)患者眼压值的差异。设计前瞻性临床试验研究。研究对象接受LASIK治疗的近视患者70例(140眼)。方法对上述患者于术前、术后1周,1、6个月用三种不同眼压计分别测量眼压,比较各时间点、各种眼压计之间的差异。同时记录手术前、后中央角膜厚度,取其两者差为角膜切削深度的值。主要指标眼压值(IOP)和角膜切削深度。结果术后1周,1、6个月DCT测量值(16.74±1.96mmHg、16.67±1.90mmHg、16.42±2.12mmHg)与其术前值(17.36±2.32mmHg)比较差异无统计学意义(F=1.346,P=0.06)。术后GAT和NCT测量值均呈下降趋势,与术前测量值比较差异有统计学意义(GAT:F=101.217,P=0.000;NCT:F=171.466,P=0.000),并且下降值与角膜切削深度成正相关关系(GAT:r=0.86,P=0.000;NCT:r=0.87,P=0.000),但术后三个时间段测量值比较差异无统计学意义(GAT术后三个时间点q值为0.216、0.677、0.461,P值分别为0.461、0.097、0.117;NCT术后三个时间点q值为0.215、0.585、0.370,P值分别为0.436、0.436、0.100)。结论LASIK术后GAT和NCT测量值明显下降,而DCT测量值无显著变化,其测量值较前两者更为可靠。(眼科,2007,16:344-347)     

动态轮廓眼压计的临床应用

目的 探讨动态轮廓眼压计(OCT)在原发性开角型青光眼(POAG)、高眼压症(OHT)、正常眼压性青光眼(NTG)及正常对照人群眼压和眼压脉动振幅(OPA)测量中的临床应用价值及影响因素.方法 选取POAG、OHT、NTG及正常对照组各30例,分别采用Goldmann压平眼压计(GAT)测量眼压,DCT测量眼压及OPA,并测量中央角膜厚度(CCT)、中央角膜曲率(CCV)以及心率、收缩压、舒张压等指标,以了解这些指标对OPA的影响.各组统计量两两比较采用q检验.各统计量之间的相关分析采用Pearson相关分析,对于多个变量之间的线性关系采用多重线性回归分析.结果 DCT测量POAG、OHT、NTG及对照组的眼压值分别为(21.68±2.02)、(23.37±2.65)、(18.43±3.08)、(17.04±2.07)lnln Hg(1 mm Hg=0.133 kPa);GAT测最的眼压值分别为(21.18±2.95)、(23.28±5.95)、(16.39±3.60)、(14.66±2.27)mm Hg.两者测量结果的差异无统计学意义(t=1.338,1.445,1.682,1.803;P=0.197,0.151,0.136,0.081).POAG、OHT、NTG及对照组的OPA值分别为3.03±1.13,3.53±1.43,2.21±0.55,2.87±0.60,组间比较差异有统计学意义(F=21.311,P=0.000);OPA值与心率、收缩压、舒张压、GAT测量值、CCT均相关,与年龄无明显相关性.结论 DCT测量结果与GAT有良好的一致性,受干扰因素少,可信度高;POAG、NTG、OHT患者和正常人的OPA存在差异,其中NCT患者OPA值明显较低,提示各组间眼内血液动力学状况的差异,OPA可能对青光眼的诊断及治疗具有一定的潜在价值.     

三种眼压计与Pentacam眼压校正系统的应用比较

目的:比较非接触式眼压计(NCT)、Goldmann压平式眼压计(GAT)、动态轮廓眼压计(DCT)和Pentacam三维眼前节分析系统四种方法检查眼压的差异,并研究它们与中央角膜厚度(CCT)和中央角膜曲率(CCV)的关系。方法:对拟行LASIK手术的143例286眼患者用Pentacam系统测量CCT和CCV后,分别用NCT,GAT和DCT测量眼压,并用Pentacam系统的Ehlers,Shah,Dresden,Orssengo/Pye和Kohlhaas5种眼压校正方法对NCT眼压值进行校正,将测量结果进行方差分析、相关性及线性回归分析。结果:DCT值最高,DCT与其他方法之间均有显著性差异(P<0.01);GAT与DCT,Kohlhaas,Shah之间有差异(P<0.05),与其他方法之间无差异;各组眼压值之间有较好的相关性,GAT与DCT的相关性最强(r=0.702);NCT受CCT影响最大,GAT受CCV影响最大,DCT,Dresden,Orssengo/Pye,Shah与CCT和CCV均不存在相关性(P>0.05)。结论:对CCT和CCV正常的健康人群进行青光眼筛查时建议使用压平式眼压计,对可疑的患者,尤其是CCT和CCV偏离正常的患者,宜进一步行DCT检查或者用Pentacam系统进行眼压校正。     

动态轮廓眼压计和非接触眼压计测量值的比较及屈光手术对其影响

目的 比较动态轮廓眼压计(DCT)和非接触眼压计(NCT)在不同屈光度患者中测量值的差异,并探讨屈光手术对DCT和NCT测量值的影响.方法 226眼按不同屈光度分3组:轻度组31眼(-1.25D～-3.00D),中度组135眼(-3.12D～- 6.00D),高度组60眼(-6.12D～- 10.625D),各组分别用NCT和DCT测量眼压,并比较不同屈光度与两种眼压计读数的差异关系.结果 屈光手术前总NCT值与屈光度无相关关系(r=0.033,P=0.626).通过控制屈光度分级的影响进行偏相关分析,DCT与屈光度的相关系数为(r=0.079,P=0.240),且无统计学意义.术前轻度组NCT和DCT测量值差异无统计学意义(t=-1.091,P=0.284);中度组和高度组的NCT和DCT值有统计学意义(t=-2.687,P=0.008;t=-3.791,P=0.000).术后各组比较:NCT和DCT测量值均有统计学意义(t=-14.493,P=0.000;t=-28.505,P=0.000;t=-24.557,P=0.000).结论 DCT测量眼压结果 不受角膜厚度、角膜曲率及眼轴长度的影响,DCT值与患眼的屈光度也无相关性,更适应于角膜屈光手术后患眼眼压的测量和评估,但对高度近视眼手术后仍应警惕眼压被低估的可能.     

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.     

Comparison of Goldmann applanation tonometry, rebound tonometry and dynamic contour tonometry in normal and glaucomatous eyes

AIM: To compare the intraocular pressure (IOP) measurements obtained with the rebound tonometry (RT), dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT) in normal and glaucomatous eyes and investigate the effects of central corneal thickness (CCT) and corneal curvature (CC) on IOP measurements. METHODS: One hundred and twenty-four eyes of 124 subjects were enrolled in this cross-sectional study. Fifty-six of participants were healthy individuals and 68 of them were glaucomatous patients. IOP was measured on each subject always in the same order, ICare RT-Pascal DCT-GAT, after a minimum interval of 10min between measurements. CCT and CC were measured using a rotating Scheimpflug camera before the IOP measurements in all subjects. One way repeated measures ANOVA, Pearson correlation coefficient and regression analysis, and Bland-Altman analysis was used for the statistical assessment. RESULTS: Mean IOP for all enrolled eyes was 16.00±3.80 mm Hg for GAT, 16.99±4.91 mm Hg for RT, and 20.40±4.44 mm Hg for DCT. Mean differences between GAT and RT was -1.75±3.41 mm Hg in normal (P<0.001) and -0.37±3.00 mm Hg in glaucomatous eyes (P=0.563). Mean differences between GAT and DCT was -4.06±3.42 mm Hg in normal (P<0.001) and -4.67±3.12 mm Hg in glaucomatous eyes (P<0.001). GAT and RT were significantly positive correlated with CCT in normal (r=0.317, P=0.017 and r=0.576, P<0.001, respectively) and glaucomatous eyes (r=0.290, P=0.016 and r=0.351, P=0.003, respectively). DCT was also significantly positive correlated with CCT in normal eyes (r=0.424, P=0.001) but not in glaucomatous eyes (r=0.170, P=0.165). All tonometers were unaffected by CC. CONCLUSION: IOP measurements by RT and DCT were significantly higher than GAT. DCT has highest IOP measurements among these tonometers. RT was most influenced tonometer from CCT although all tonometers were significantly positive correlated with CCT except DCT in glaucomatous eyes. CC did not influence IOP measurements.     

Comparisons between Pascal dynamic contour tonometry, the TonoPen, and Goldmann applanation tonometry in patients with glaucoma

PURPOSE: To compare intraocular pressure (IOP) measurements taken with Pascal dynamic contour tonometry (DCT), the TonoPen and the Goldmann applanation tonometry (GAT). The influence of central corneal thickness (CCT) on IOP measurements taken with Pascal DCT and the TonoPen was evaluated. METHODS: One eye in each of 101 consecutive patients with primary open-angle glaucoma (POAG) underwent ultrasonic CCT measurement and IOP evaluation with GAT, Pascal DCT and the TonoPen in random order. The agreement between results from Pascal DCT and the TonoPen and those of GAT was assessed using the Bland-Altman method. The deviation of Pascal DCT and TonoPen readings from GAT values, corrected for CCT, was calculated and correlated to CCT using a linear regression model. RESULTS: The mean of the differences in IOP measurements was 3.2 +/- 2.4 mmHg for Pascal DCT minus GAT readings and 0.5 +/- 4.5 mmHg for TonoPen minus GAT readings. The 95% confidence interval of differences in IOP measurements was higher between TonoPen and GAT readings (- 6 to 7 mmHg) than between Pascal and GAT readings (0.1-6.8 mmHg). Pascal DCT significantly overestimated IOP compared with GAT, especially for higher IOP readings. Bland-Altman scatterplots showed reasonable inter-method agreement between Pascal DCT and GAT measurements, and poor agreement between TonoPen and GAT measurements. The deviations of Pascal DCT and TonoPen readings from the corrected GAT values were both highly correlated with CCT values (linear regression analysis, p < 0.0001). The mean change in measured IOP for a 10-microm increase in CCT was 0.48 mmHg for Pascal DCT and 0.74 mmHg for the TonoPen. CONCLUSIONS: Agreement with GAT measurements was higher for Pascal DCT than for TonoPen readings; however, Pascal DCT significantly overestimated IOP values compared with GAT. Measurements of IOP obtained with both Pascal DCT and the TonoPen appeared to be influenced by CCT, and this influence appeared to be greater for the latter.     

Comparison of dynamic contour tonometry with Goldmann applanation tonometry in glaucoma practice

Purpose: To compare intraocular pressure (IOP) readings taken using dynamic contour tonometry (DCT) with IOP readings taken with Goldmann applanation tonometry (GAT) in eyes with glaucoma or ocular hypertension. Methods: The present study included 100 eyes in 100 patients with glaucoma or ocular hypertension. After pachymetry DCT and GAT were performed. Intraocular pressures as measured with DCT and GAT were compared with one another and with central corneal thickness (CCT). Results: Mean DCT IOP measurements (20.1 ± 4.3 mmHg) were significantly (p < 0.001) higher than GAT IOP values (17.9 ± 4.7 mmHg). The mean difference between DCT and GAT measurements was 2.1 mmHg (range ? 3.4 to 9.7 mmHg). The difference followed a normal distribution. Measurements made with DCT and GAT correlated significantly with one another (Spearman’s rho = 0.761, p < 0.001). Neither GAT nor DCT measurements showed a significant correlation with CCT (537 ± 39 μm, range 458–656 μm). Multivariate regression analysis has shown that the difference between DCT and GAT is influenced significantly by ocular pulse amplitude (r = ? 0.334, p = 0.001) and it is not influenced by CCT (r = ? 0.106, p = 0.292). Conclusions: In eyes with glaucoma or ocular hypertension, DCT facilitates suitable and reliable IOP measurements which are in good concordance with GAT readings. Variation in CCT cannot by itself explain the differences in measurements taken with DCT and GAT in a number of eyes.     

Comparison of dynamic contour tonometry and goldmann applanation tonometry in deep lamellar and penetrating keratoplasties

PURPOSE: To compare the measurements of intraocular pressure (IOP) with dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT) in eyes with corneal graft and to evaluate the influence of corneal thickness (CCT), corneal curvature (CC), and astigmatism on these methods. DESIGN: Prospective, observational cross-sectional study. METHODS: Eighteen eyes of 18 patients after penetrating keratoplasty (PKP) and 14 eyes of 14 patients after deep lamellar keratoplasty (DLKP) underwent IOP evaluation with DCT and GAT, and measurements of CCT, CC, and astigmatism. Bland-Altman plots were used to evaluate the agreement between tonometers. Multivariate regression analysis was used to evaluate the influence of ocular structural factors and running suture on IOP measurements obtained with both tonometers. RESULTS: IOP values obtained by DCT and GAT were strongly correlated in all eyes (r = .91; P < .001). DCT values measured 2.5 +/- 1.7 mm Hg higher than GAT readings (P < .001). A reduction of the mean IOP difference between DCT and GAT with an increase in IOP values (P < .001) was found. Regression analysis showed no effect of CCT, CC, astigmatism, and running suture on both DCT and GAT readings, either in DLKP or in PKP eyes. CONCLUSIONS: We found a good overall correlation between both tonometers but the agreement between instruments differs in high or low IOP ranges. The wide and varying 95% limits of agreement between DCT and GAT indicates that DCT provides IOP measurements on deep lamellar and penetrating keratoplasties which can be used in the clinical practice.     

Comparison of dynamic contour tonometry with goldmann applanation tonometry

PURPOSE: The dynamic contour tonometer (DCT; Pascal tonometer) is a novel tonometer designed to measure intraocular pressure (IOP) independent of corneal properties. The purpose of this study was a comparison of the DCT with the Goldmann applanation tonometer (GAT) with respect to mean of IOP readings, the influence of ocular structural factors on IOP readings, and both intra- and interobserver variability, in a large group of healthy subjects. METHODS: In a prospective study of 228 eyes, IOP measurements by GAT and DCT were compared, and the effects of central corneal thickness (CCT), corneal curvature, axial length, and anterior chamber depth were analyzed. To evaluate intra- and interobserver variability, IOP was measured in eight eyes by four observers. RESULTS: There was a high concordance between the IOP readings obtained by DCT and GAT. However, IOP readings were consistently higher with DCT than with GAT (median difference: +1.7 mm Hg, interquartile range [25th-75th percentile] = 0.8-2.7 mm Hg). In contrast to GAT, multivariable regression analysis showed no significant effect of corneal thickness, corneal curvature, astigmatism, anterior chamber depth, and axial length on DCT readings. For repeated measurements the intraobserver variability was 0.65 mm Hg for the DCT and 1.1 mm Hg for the GAT (P = 0.008). Interobserver variability was 0.44 mm Hg for the DCT and 1.28 mm Hg for the GAT (P = 0.017). CONCLUSIONS: IOP measurements by DCT are highly concordant with IOP readings obtained from GAT but do not vary in CCT and have a lower intra- and interobserver variability. DCT seems to be an appropriate method of tonometry for routine clinical use.     

Comparison of dynamic contour tonometry with goldman applanation tonometry over a wide range of central corneal thickness

PURPOSE: To compare dynamic contour tonometry with Goldmann applanation tonometry in structurally normal corneas over a wide range of central corneal thickness (CCT). PATIENTS AND METHODS: Twenty-five patients each with normal CCT (group A), thin corneas (group B), and thick corneas (group C) had IOP measured with the Goldmann (GAT) and dynamic contour tonometer (DCT). RESULTS: In group A (mean CCT = 552 +/- 16 microm) the mean GAT was 15.9 +/- 3.1 mm Hg and mean DCT was 16 +/- 3.3 mm Hg (P = 0.91). In group B (mean CCT = 491 +/- 19 microm) the mean GAT was 13.2 +/- 3.5 mm Hg and the mean DCT was 15.9 +/- 3.5 mm Hg (P = 0.009). For group C (mean CCT = 615 +/- 22 microm), the mean GAT was 17.4 +/- 3.8 mm Hg and the mean DCT was 17.4 +/- 3.5 mm Hg (P = 0.95). The 95% agreement limits for DCT were -3.1 mm Hg to 2.9 mm Hg. The mean GAT-DCT difference was -2.6 mm Hg in thin corneas and -0.06 mm Hg in thick corneas. Below 520 microm reduction of 10 microm in CCT appears to result in a significant underestimation of the GAT IOP by 0.7 mm Hg (P < .001) and above 580 microm a non-significant overestimation of 0.2 mm Hg per 10 microm increase in CCT (P = 0.27). CONCLUSION: Dynamic contour tonometer agrees well on average with GAT but the agreement limits are wide. In structurally normal thin corneas DCT may give a more accurate assessment of the true IOP but it does not appear to have any benefit over GAT in thick corneas.     

Comparative evaluation of TonoPen AVIA,Goldmann applanation tonometry and non-contact tonometry

To compare the tonometric recordings of the Tono-Pen AVIA (TPA) with intraocular pressure (IOP) recordings made with Goldmann applanation tonometry (GAT) and non-contact tonometry (NCT). This prospective, observational, comparative case series consisted of 180 eyes of 180 subjects (50 patients with glaucoma and 130 healthy controls). NCT was performed first, followed by GAT and TPA measurement after a 5-min break. The mean age of the patients enrolled in the study was 43.99 ± 16.67 years. The limits of agreement (confidence interval 95%) as calculated from the Bland–Altman plots for TPA–GAT and TPA–NCT were +8.7 to −7.7 and +8.6 to −9.6 mmHg in glaucoma patients. In healthy subjects these values were +4.8 to −5.1 and +6.2 to −5.2 mmHg, respectively. TPA tends to overestimate IOP compared to GAT at central corneal thickness (CCT) greater than 520 μm and underestimate IOP at CCT less than 510 μm. TPA overestimates IOP in comparison to NCT in subjects with CCT greater than 456 μm. Due to wide limits of agreement, TPA cannot be used interchangeably with GAT and NCT in the serial monitoring of glaucoma patients. Central corneal thickness has a significant influence on the IOP readings measured by Tono-Pen AVIA.     

Intraocular pressure and ocular pulse amplitude comparisons in different types of glaucoma using dynamic contour tonometry

PURPOSE: To compare the intraocular pressures (IOP) and ocular pulse amplitudes (OPA) in patients with different types of glaucoma, ocular hypertension (OHT), and normal controls (NC) using dynamic contour tonometry (DCT) and the goldmann applanation tonometry (GAT). METHODS: 906 eyes of 501 adult patients in the following five groups were included in this cross-sectional study: primary open angle glaucoma (POAG), normal tension glaucoma (NTG), Pseudoexfoliative Glaucoma (PXG), OHT, and NC. The following tests were performed simultaneously during a single visit: IOP using DCT and GAT; OPA using DCT and central corneal thickness (CCT) using ultrasound pachymetry. Mixed effects regression models were used to compare the DCT and GAT IOP measurements in the five groups; the effect of CCT on IOP and the relationship between OPA and IOP within each group. RESULTS: DCT consistently had higher IOP values than GAT in POAG, PXG, NTG, and controls (p < 0.001) but not in OHT (p = 0.84). DCT IOP did not change while GAT IOP showed a non-significant increase (p = 0.09) with increased corneal thickness in each group. OPA was found to be highest in OHT (3.61 mmHg) and lowest in the control group (2.86 mmHg) and significantly increased with IOP in all groups. CONCLUSIONS: DCT measures an IOP that is significantly higher than GAT IOP in glaucoma and control subjects but not in ocular hypertensives. Furthermore, the DCT may measure an IOP that is independent of the CCT, which may not be true for the GAT, which increases with the CCT. OPA was highest in OHT and may be affected by the IOP.