Dynamic Contour Tonometry in Comparison to Intracameral IOP Measurements

Boehm, Andreas; Weber, Anja; Pillunat, Lutz E.; Koch, Rainer; Spoerl, Eberhard

doi:10.1167/iovs.07-1366

Cited by 97 publications

(89 citation statements)

References 26 publications

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“…There are varied results in the literature for proportional bias; some studies have, like us, found no bias between DCT and GAT measurement, 25,28 others have found increasing differences between DCT and GAT as IOP increased, 29,30 or decreasing differences in another. 31 DCT values for IOP are similar to intracameral manometric IOP in vivo 32 and are more similar than GAT (which are significantly lower) in cadaveric eyes. 33,34 This may mean that the higher IOP readings obtained with DCT are in fact the 'true' IOP.…”

Section: Discussionsupporting

confidence: 51%

Comparison of three methods of intraocular pressure measurement and their relation to central corneal thickness

Carbonaro

Andrew

Mackey

et al. 2010

Eye

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Purpose The purpose of this study was to compare the reliability of the 'gold standard' Goldmann applanation tonometer (GAT), with that of the ocular response analyser (ORA), and the dynamic contour tonometer (DCT). Patients and methods A total of 694 subjects were recruited to participate from the TwinsUK (UK Adult Twin Registry) at St Thomas' Hospital, London. Intraocular pressure (IOP) was measured using GAT, ORA, and the DCT. The agreement between the three methods was assessed using the Bland-Altman method. Repeatability coefficients and coefficient of variation between first and second readings of the same eye were used to assess reliability. Results Mean age was 57.5 years (SD, 13.1; range, 16.1-88.5). The mean IOPs, calculated using the mean of two readings from the right eye were as follows: Goldmann (GAT), 14.1 ± 2.8 mm Hg; IOPg (ORA), 15.9 ± 3.2 mm Hg; IOPcc (ORA), 16.6 ± 3.2 mm Hg; and DCT, 16.9 ± 2.7 mm Hg. The 95% limits of agreement were for ORA (IOPcc): GAT, À2.07 to 7.18 mm Hg; for DCT: GAT, À0.49 to 6.21 mm Hg; and for DCT: ORA (IOPcc), À3.01 to 4.85 mm Hg. Coefficients of variation for the three tonometers were GAT, 8.3%; ORA, 8.2%; DCT, 6.3%. The repeatability coefficients were 3.4 mm Hg for GAT, 3.57 mm Hg for ORA and 3.09 mm Hg for DCT. GAT and ORA (IOPg) readings showed a positive correlation with central corneal thickness (Po0.005). Conclusions This study found similar reliability in all three tonometers. Bland-Altman plots showed the three instruments to have 95% limits of agreement outside the generally accepted limits, which means they are not interchangeable. GAT measurements were found to be significantly lower than the two newer instruments.

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Section: Discussionsupporting

confidence: 51%

Comparison of three methods of intraocular pressure measurement and their relation to central corneal thickness

Carbonaro

Andrew

Mackey

et al. 2010

Eye

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“…DCT is more accurate than Langham ocular blood flow 30 in measuring the IOP and OPA and was recently shown to have good concordance with intracameral IOP. 31 Recent studies showed a positive correlation between DCTs OPA and IOP. 32 Similar to the reports in literature they were positively correlated in our study population.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of ocular pulse amplitude and choroidal thickness in diabetic macular edema

Totan

Akyüz

Güler

et al. 2015

Eye

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Purpose The aim of this study is to evaluate the ocular pulse amplitude (OPA) and choroidal thickness (CT) measurements in patients with diabetic macular edema (DME) and healthy subjects. Methods A total of 34 patients (12 male and 22 female) who had type 2 diabetes mellitus with DME and 34 sex-matched healthy subjects (13 male and 21 female) were included in this prospective study. The intraocular pressure (IOP) and OPA were measured with Dynamic contour tonometer (Pascal DCT, Switzerland). The subfoveal CT was measured using the Cirrus HD-OCT (Carl Zeiss Meditec). The CT at 1500 μm and 3000 μm nasal and temporal to the central fovea was also measured. Results The mean IOP values were 18.4 ± 3.5 and 17.1 ± 2.1 mm Hg in DME patients and healthy controls, respectively (P = 0.091). The mean OPA values in patients with DME (2.58 ± 0.96) and controls (3.52 ± 1.03) were statistically different (Po0.001). The mean subfoveal CT value was 273.5 ± 30.2 μm in the eyes with DME and 321.4 ± 36.5 μm in the control group (Po 0.001). In both groups, linear regression analysis showed no significant association between OPA and CT measurements. The IOP showed a significantly positive correlation with OPA in both DME (P = 0.002, r = 0.526) and controls (P = 0.004, r = 0.483). Conclusions The current study suggests that both pulsatile choroidal blood flow and CT are decreased in patients with DME.

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“…15,27 Whilst methods that improve the estimate of IOP and decrease the effects of errors are a welcome development, it should be remembered that the error reduction is an average effect across a population; corrections at an individual level result in measurements that are likely to be more accurate, however, the corrections are made with parameters associated with biomechanical properties, rather than the biomechanical properties themselves, so correction errors at the individual level may occur. This study evaluated by both univariate and multivariate analyses the association of biomechanical parameters with IOP as measured using the GAT (IOPG) and after correction using the five available multi-parameter correction equations.…”

Section: Discussionmentioning

confidence: 99%

“…5 As identified previously, the IOP measurements obtained using the GAT (IOPG) are known to vary with changes in biomechanical parameters that affect corneal stiffness, predominantly the central corneal thickness (CCT), 6,7 central corneal radius of curvature (R), 8,9 hydration, 10,11 ectasia, 12 and age. 13,14 Recently studies have reported that the 'new age' tonometers like the Pascal dynamic contour tonometer (DCT) 15 and the ocular response analyzer 16 are less affected by the physiological variations in the biomechanical parameters of the cornea. However, these devices are not available universally and the GAT remains the most commonly used device to measure IOP.…”

Section: Introductionmentioning

confidence: 99%

Clinical evaluation of multiparameter correction equations for Goldmann applanation tonometry

Davey

Elsheikh

Garway-Heath

2013

Eye

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Purpose To evaluate and compare the multiparameter equations in correcting intraocular pressure (IOP) measurements obtained using the Goldmann applanation tonometer (IOPG) for the effects of central corneal thickness (CCT), corneal curvature (R), and age in different ethnic populations. Methods Data of IOPG, CCT, R, and age were collected from three clinical centers. The sample size consisted of 945 eyes of 945 glaucoma patients or suspects (669 Europeans, 127 African Americans, and 149 Indians). The 'corrected IOP' was calculated using five multiparameter equations to decrease the association of CCT, R, and age with measured IOP. Regression analyses were performed to calculate variance (r 2 ) and determine the association of CCT, R, and age with IOPG and corrected IOP (residual association). Results Overall, CCT accounted for the majority of variance in IOPG, while R and age had a much smaller effect, with the combined effect on IOPG ranging from 4.7 to 7.5% in the three data sets. The residual association of CCT, R, and age with corrected IOP in the three groups ranged from 0.2 to 1.3% and 0.5 to 1.8% with the application of the Elsheikh and the Chihara equations, respectively. The residual association of CCT, R, and age with corrected IOP calculated using the Ehlers, Orssengo and Pye, and Shimmoyo equations were 7-11.5, 1.8-11.7, and 4.6-8.3%, respectively. Conclusion The Elsheikh and the Chihara equations better decreased the association of CCT, R, and age with measured IOP than the Ehlers, Orssengo and Pye, and Shimmoyo equations.

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Dynamic Contour Tonometry in Comparison to Intracameral IOP Measurements

Abstract: Measurements with the DCT showed good concordance with intracameral IOP. CCT exerted a statistically significant but clinically irrelevant effect on measurements with the DCT.

Cited by 97 publications

References 26 publications

Comparison of three methods of intraocular pressure measurement and their relation to central corneal thickness

Comparison of three methods of intraocular pressure measurement and their relation to central corneal thickness

Evaluation of ocular pulse amplitude and choroidal thickness in diabetic macular edema

Clinical evaluation of multiparameter correction equations for Goldmann applanation tonometry

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