动态轮廓眼压计与压平眼压计的比较

目的:评价和比较动态轮廓眼压计和Goldmann压平眼压计测得的LASIK手术后眼压值。方法:接受准分子激光原位角膜磨镶术(LASIK)的近视患者34例68眼,分别于术前和术后3mo使用动态轮廓眼压计(Pascal dynamic contour tonometer,PDCT)和Goldmann压平眼压计(the Goldmann applanation tonometer,GAT)进行眼压测量。比较手术前后两种测量方法测得的眼压值的差异。多元线性相关分析研究GAT,PDCT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手术后GAT测量值较术前低,而PDCT值和术前比较差异则无统计学意义。角膜曲率、CCT和GAT读数呈线性相关,而与PDCT读数无关。结论:GAT测量得到的眼压低于实际值。PDCT测眼压不受角膜曲率和中央角膜厚度影响。     

轮廓动态眼压计测量准分子激光原位角膜磨镶术后眼压

目的通过与Goldmann眼压计(goldmann appla-nation tonometer,GAT)的比较,评价轮廓动态眼压计(dynamiccontour tonometer,DCT)在准分子激光原位角膜磨镶术(laser insitu keratomileusis,LASIK)前和术后眼压测量中的应用价值。方法在术前以及术后第1周和第4周,分别用GAT和DCT测量30例60眼的眼压,对所得结果采用SPSS 11.5统计分析软件进行统计学处理。结果中央角膜厚度(centralcorneal thickness,CCT)和GAT读数相关,而与DCT读数无关。术前眼压和术后第1周、第4周的眼压比较,GAT读数分别下降(5.00±1.12)mmHg和(5.45±1.13)mmHg,DCT则无显著性差异。结论LASIK导致的CCT变化可影响GAT测量结果的准确性,但对DCT无影响,因此,DCT更适用于正常眼以及曾接受LASIK手术眼的眼压测量。     

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。     

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。     

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)     

动态轮廓眼压计和Pentacam眼压校正系统在LASIK手术前后应用比较

目的比较动态轮廓眼压计（DCT）和Pentacam眼压校正系统在LASIK手术前后的应用价值。方法对行LASIK手术的65例（129眼）于术前和术后1个月用Pentacam系统测量中央角膜厚度（CCT）和角膜曲率（CCV）后,分别用非接触眼压计（NCT）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,将测量结果进行统计学分析。结果DCT值在手术前后均最高,DCT值和Ehlers法校正值术前与术后比较差异无统计学意义（P〉0．05）;其他方法眼压校正值术前与术后比较,差异均有统计学意义（P〈0．01）,术前与术后各组眼压值之间呈正相关性;DCT测量值在LASIK手术前后与CCT、CCV均无相关性（P〉0．05）,Pentacam的各组校正值在术前和术后均与CCT和CCV有密切的关系。结论DCT测量眼压不受CCT和CCV的影响,可作为LASIK术后眼压测量的首选方法,Pentacam系统Ehlers校正法是对LASIK术后准确测量眼压的有力补充。     

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。     

Pascal动态轮廓眼压计在角膜屈光手术前后的应用

目的 探讨Pascal动态轮廓眼压计(dynamic contour tonometer,DCT)在角膜屈光手术前后的应用.方法 随机收集我院2009年1月至6月拟接受角膜屈光手术的屈光不正患者127例(254眼),其中男51例(102眼),女76例(152眼);年龄18～47岁,平均(22.48±3.57)岁.中央角膜厚度(central corneal thickness,CCT)为450～600 μm,平均等效球镜度数为-0.75～10.00 D.术前及术后1个月分别采用DCT和非接触式眼压计(non-contact tonometer,NCT)测量眼压,角膜超声测厚仪测量CCT,并分析眼压与CCT变化的关系.结果 术前:450 μmm550 μm时,NCT测得眼压平均值分别为(11.51±3.25)mmHg(1kPa=7.5 mmHg)、(17.58±2.97)彻Hg、(19.74±3.12)nHg,DCT测得眼压平均值分别为(16.89±2.56)mmHg、(17.33±3.32)mmHg、(17.58±2.74)mmHg,当450 μm550 μm时,DCT与NCT测得的眼压平均值比较,差异均有统计学意义(均为PO.05);术后1个月:当△CCT≤50 μm、50μm<△ccT≤100μm和△cCT>looμm时,NCT测得眼压较术前分别下降(1.46±0.81)mmHg、(3.87±1.21)mmHg、(4.19±2.68)mmHg,与术前相比差异均有统计学意义(P<0.05、P0.05).结论 DCT受角膜厚度影响较小,是角膜屈光手术前后眼压测量的一种好方法,尤其对于手术前眼压偏高的患者意义更大.     

LASIK前后眼压测量方法选择

目的 比较四种常用眼压计在近视准分子激光原位角膜磨镶术(Laserin situ eratomileusis,LASIK)前后的应用,探讨LASIK手术前后眼压测量方式的选择,以做到术前高眼压患者筛查及术后患者青光眼的早期发现.方法 对71例接受LASIK手术近视眼患者按等效球镜分为三组,分别在术前和术后1个月和3个月采用Schiotz眼压计(Schiotztonometer,ST)、Goldmann眼压计(Goldmann applanationtonometry,GAT)、非接触眼压计(non-contacttonometer,NCT)和Tono-Pen眼压计(TP)测量眼压,同时记录手术前后角膜中央厚度.结果 各屈光度组间同时间点相同眼压计测量值差异无统计学意义,术前除GAT、TP外其他眼压计差异有统计学意义,术后各眼压计测量值均降低,TP受角膜变化影响较小,GAT及NCT受影响明显,三者均与术前GAT值相关.ST不受角膜变化影响但其测量值明显偏高且术后与术前GAT无相关关系.结论 术前采用TP或GAT均可,术后应用TP,而NCT可作为术前筛查辅助手段.ST的应用仍有待探讨.     

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。     

Intraocular pressure measurements using dynamic contour tonometry after laser in situ keratomileusis

PURPOSE: Thinning of the corneal stroma by laser in situ keratomileusis (LASIK) results in inaccurate low intraocular pressure (IOP) readings by Goldmann applanation tonometry (GAT). Dynamic contour tonometry (DCT) is a novel measuring technique, designed to measure IOP largely independent of corneal thickness and curvature. The purpose of this study was to compare IOP measurements using GAT and DCT in eyes undergoing LASIK for correction of myopia. METHODS: In a prospective, single-center study, central corneal thickness (CCT) and IOP were measured in patients undergoing first-time LASIK for myopia. IOP was measured before and after surgery using GAT and DCT. The untreated contralateral eyes served as paired controls. RESULTS: There was good concordance between the two tonometers in 62 normal eyes before LASIK. Corneal ablation of 90.0 +/- 49.18 micro m (median +/- SD) reduced IOP readings as measured by GAT by 3.0 +/- 1.9 mm Hg (P < 0.001). In contrast, no significant change in IOP readings was recorded by DCT (-0.2 mm Hg +/- 1.5 mm Hg, P = 0.30). There was no change in IOP in the untreated control eyes as measured by GAT and DCT. CONCLUSIONS: Significant decreases in IOP were recorded by GAT after LASIK for myopia. Measurements by DCT, however, did not reveal any significant changes in IOP.     

A comparison between Goldmann applanation tonometry and dynamic contour tonometry after photorefractive keratectomy

Background

The intraocular pressure (IOP) could be measured by both Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT). Although these two methods have been discussed widely after laser-assisted sub-epithelial keratectomy (LASIK), there is little data in the cases undergoing photorefractive keratectomy (PRK). We aimed to compare the changes of IOP measurements obtained by GAT and DCT after PRK for myopia/myopic astigmatism.

Methods

This prospective study enrolled 77 candidates (154 eyes) for PRK to correct myopia or myopic astigmatism and 30 matched patients (30 eyes) with myopia or myopic astigmatism who served as controls. Changes of the IOP measurements (ΔIOP) obtained by GAT and DCT before and at 6 months after PRK in the operated eyes, and at baseline and 6 months later in the controls, were documented. Changes of the central corneal thickness (ΔCCT) were determined in the same fashion.

Results

The mean IOP readings obtained by DCT were comparable before and at 6 months after procedure (18.34 ± 3.03 mmHg and 17.87 ± 2.61 mmHg respectively, p?=?0.41); whereas the mean IOP reading obtained by GAT decreased significantly 6 months postoperatively (17.92 ± 3.63 mmHg and 16.25 ± 2.66 mmHg, p?<?0.001). A significant correlation was present between the ΔIOP obtained by GAT and ΔCCT (r?=?0.61, p?<?0.001). Similar correlation was not significant between the DCT-obtained ΔIOP and the ΔCCT (r?=?0.07, p?=?0.44). The mean ΔIOP obtained by GAT was significantly higher in the operated eyes than in the controls (?1.54?±?1.45 vs 0.07?±?0.44 mmHg, p?=?0.02). The mean DCT-obtained ΔIOP was just marginally insignificant between the operated and nonoperated eyes (?0.63?±?0.59 vs 0.02?±?0.38 mmHg respectively; p?=?0.09).

Conclusions

The authors recommend DCT after PRK in the cases with myopia or myopic astigmatism     

Evaluation of the Orssengo-Pye IOP corrective algorithm in LASIK patients with thick corneas.

BACKGROUND: The objective of this study was to evaluate the Orssengo-Pye central corneal thickness (CCT) Goldmann applanation tonometry (GAT) corrective algorithm by observing changes in GAT and CCT before and after laser in situ keratomileusis (LASIK) surgery in patients with CCT that remains greater than 545 microm postoperatively. METHODS: Tonometric and pachymetric measurements were made on 14 patients (28 eyes) before and after LASIK surgery. The selected patients were required to have average or above average postoperative central corneal thickness values in both eyes (not less than 545 microm). Preoperatively, all patients had CCT and GAT measurements taken. Postoperatively patients had CCT, GAT, and dynamic contour tonometric (DCT) measurements taken. RESULTS: Preoperatively, median CCT values were 589.536 microm. Median GAT values were 16.750 mmHg. Median corrected preoperative GAT values were 14.450 mmHg. After LASIK treatment, median CCT values were 559.417 microm. The decrease in median CCT was 30.119 microm. Median postoperative GAT values were 11.500 mmHg (decrease, 5.250 mmHg). Median corrected postoperative GAT values were 10.775 mmHg (decrease, 3.675 mmHg). Median postoperative DCT values were 17.858 mmHg. CONCLUSIONS: LASIK treatment causes a significant reduction in measured GAT intraocular pressure (IOP) values. The Orssengo-Pye formula, which attempts to correct for GAT error associated with individual variation in CCT, appears to yield misleading results in these circumstances. An unexpected 3.675-mmHg decrease in "corrected IOP" by the Orssengo-Pye method seen in this study may be attributed to some limitation or error in the formula. After adjusting for the approximate1.7-mmHg difference, which has been demonstrated between DCT and GAT, postoperative DCT values were similar to preoperative measured GAT values.     

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.     

三种眼压计在准分子激光原位角膜磨镶术后的应用比较

目的评价三种不同眼压计在近视准分子激光原位角膜磨镶术后的应用。方法对近视33例66眼和LASIK术后43例86眼分别用非接触眼压计(non—contact tonometer NCT)，Goldmann压平眼压计(Godmann applanalion tonometer，GAT)和Tono-Pen压平眼压计测量眼压(Tono—Pen眼压计测量角膜中央和颞下距角膜缘1．5～2mm处的眼压)，同时测角膜中央及颞下方的厚度。结果用三种方法测得的近视眼LASIK术后的眼压测量值均明显低于正常近视眼。两组均为Tono—Pen和NCT、与GAT测量值呈正相关，LASIK术后中央Tbno—Pen眼压测量值与术前GAT呈正相关。眼压与角膜厚度的关系：近视眼组，NCT与角膜中央厚度呈正相关；GAT和Tono—Pen与角膜厚度无相关性。LASIK术后组，GAT和NCT与角膜厚度呈正相关；Tono-Pen与角膜中央厚度无相关性。结论LASIK术后眼压测量值下降。Tono—Pen测量IOP不受角膜厚度的影响，可应用于LASIK术后等角膜表面不平者。     

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.     

Reproducibility of dynamic contour tonometry. Comparison with TonoPenXL and Goldmann applanation tonometry - a clinical study on 323 normal eyes

BACKGROUND: The PASCAL Dynamic Contour Tonometer (DCT) is a new diagnostic approach for the digital measurement of intraocular pressure (IOP) in eyes with glaucoma. The aim of this study was to evaluate the reproducibility of DCT in normal eyes and to compare DCT with Goldmann applanation tonometry (GAT) and TonoPenXL. PATIENTS AND METHODS: A prospective cross-sectional study on 323 normal, consecutive eyes was performed. Eyes with an IOP of more than 23 mmHg (GAT) were excluded. Central corneal power (Zeiss Ophthalmometer) and central corneal thickness (ultrasound pachymetry: Tomey AL-1000) were taken. The IOP readings were obtained as follows: 3 x DCT [quality of measurement, IOP and ocular pulse amplitude (OPA) were taken], 1 x TonoPenXL, GAT, finally: once again DCT to evaluate the tonography effect. RESULTS: The quality of 3 following IOP (DCT) readings was good (quality Q1 = 43.4 %, Q2 = 32.5 %, Q3 = 22.7 %). The reproducibility of the IOP (DCT) measurements was excellent (first measurement IOP (DCT) = 18.1 +/- 3.4 mmHg, second measurement IOP (DCT) = 18.1 +/- 3.4 mmHg, third measurement IOP (DCT) = 17.8 +/- 3.4 mmHg, Cronbach's alpha = 0.976). First and second IOP (DCT) values showed a strong correlation (r = 0.93). A significant tonography effect was observed between first and third IOP (DCT) measurements (0.4 mmHg; p = 0.004). Mean OPA (DCT) was 3.0 mmHg during the first three measurements (Cronbach's alpha = 0.964). IOP (DCT) and OPA (DCT) reproducibility showed no laterality. IOP (DCT) (17.7 +/- 3.4 mmHg) was significantly higher than IOP (TonoPenXL) (16.0 +/- 3.2 mmHg, n = 275; p < 0.001) and higher than IOP (GAT) (14.5 +/- 3.1 mmHg, n = 275; p < 0.001). The effect of tonography between the third and last IOP (DCT) measurement was zero (p = 0.6). IOP (DCT) and IOP (GAT) values were only weak correlated with central corneal thickness. CONCLUSIONS: IOP and OPA values measured with the DCT are extraordinary reproducible in normal eyes. Frequently, DCT detects higher IOP values than those obtained with TonoPenXL and GAT. A reproducible measurement of IOP and OPA may open new diagnostic fields, e. g., in glaucoma detection or ocular vascular diseases.     

Physiological diurnal variability and characteristics of the ocular pulse amplitude (OPA) with the dynamic contour tonometer (DCT-Pascal<Superscript>®</Superscript>)

PURPOSE: The Pascal dynamic contour tonometer (DCT) allows measurement of intraocular pressure (IOP) independently of corneal properties. It records, simultaneously, haemodynamic IOP fluctuations and the difference between the systolic and the diastolic IOP corresponding to the ocular pulse amplitude (OPA). The OPA indirectly reflects choroidal perfusion and could be considered as an independent risk factor in glaucoma. We aimed to establish the physiological diurnal variability of the OPA and its correlations with other biophysical parameters because its characteristics remain partly unclear. METHOD: Prospective study including 52 eyes of 28 normal subjects with Goldmann applanation tonometry (GAT) IOPs < 22 mmHg. Subjects treated with systemic medications that could interfere with blood pressure or heart rate were excluded. IOP was measured at 9:00 am, 1:00 pm, and 4:00 pm by GAT and DCT. Two consecutive GAT followed by three consecutive DCT measurements were performed in each session by the same clinician (SP). Only DCT measurements with quality 1 and 2 were taken into account. Blood pressure, pulse rate, and central corneal thickness (CCT) were recorded after the last IOP measurements. Spearman correlation coefficient was used for assessment of correlations. RESULTS: Mean age was 40 +/- 14 years. Mean DCT values were significantly higher than GAT readings (mean = 16.8 +/- 2.0 vs. 15.2 +/- 2.8 mmHg, P < 0.02). The mean OPA was 2.2 +/- 0.7 mmHg (range: 1-3.4 mmHg). The mean amplitude of diurnal OPA fluctuations was 0.4 mmHg. There was no significant difference in the mean OPA values at each time of the diurnal curve. The intraclass correlation (ICC) of only one OPA measurement in relation to part of total variance due to inter-measurement variation was 78%. Averaging over three independent readings of OPA improved ICC to 91%. The OPA was correlated with GAT (r = 0.31, P < 0.0001) and DCT IOP measurements (r = 0.49, P < 0.0001). It was correlated neither with blood pressure nor with age. OPA values of both eyes of the same individual were highly correlated (r = 0.89, P < 0.0001). CONCLUSION: In normal healthy eyes, the ocular pulse amplitude remains stable during normal outpatient office hours and was not correlated with blood pressure or age of patients.