Accuracy of dynamic contour tonometry compared with applanation tonometry in human cadaver eyes of different hydration states

Kniestedt, Christoph; Nee, Michelle; Stamper, Robert L.

doi:10.1007/s00417-004-1024-6

Cited by 91 publications

(72 citation statements)

References 28 publications

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“…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: Discussionmentioning

confidence: 99%

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: Discussionmentioning

confidence: 99%

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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“…Dynamic Contour Tonometry) durch biomechanische Eigenschaften der Hornhaut weniger beeinflusst wird als die herkömmlichen Messgeräte [9,10,13,16,18,19] . 3).…”

Section: Okuläre Pulsamplitude Als Biometrischer Messwert In Der Glauunclassified

Okuläre Pulsamplitude als biometrischer Messwert in der Glaukomdiagnostik

Romppainen

Kniestedt

Bachmann³

et al. 2007

Ophthalmologe

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“…[10][11][12][13] Using DCT IOP as a reference standard, the difference between DCT and GAT measurements increased with increasing IOP (P < 0.001) (Fig. 3).…”

Section: Impact Of Corneal Deformation Amplitude On Iop Measurementmentioning

confidence: 99%

An Ultra-High-Speed Scheimpflug Camera for Evaluation of Corneal Deformation Response and Its Impact on IOP Measurement

Leung

Weinreb

2013

Invest. Ophthalmol. Vis. Sci.

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PURPOSE.To investigate the test-retest variability of and factors associated with the corneal deformation response, and evaluate its impact on IOP measurement.METHODS. Forty normal and 140 glaucoma suspect/glaucomatous eyes of 104 individuals were prospectively included for repeated measurements of corneal deformation response by an ultra-high-speed Scheimpflug camera, followed by corneal hysteresis and corneal resistance factor measurements by the ocular response analyzer, and dynamic contour tonometry (DCT) (the reference standard) and Goldmann applanation tonometry (GAT) during the same visit. The test-retest variability of corneal deformation response was evaluated. Univariate and multivariate linear mixed models were used to identify factors (age, manifest spherical refractive error, axial length, IOP, central corneal thickness [CCT], corneal curvature, corneal hysteresis, and corneal resistance factor) associated with corneal deformation response and the difference between DCT and GAT measurements. RESULTS.Corneal deformation amplitude (CDA) had an intraclass correlation coefficient of 0.86. There was no difference in CDA between the glaucoma and nonglaucoma groups. A higher IOP, a younger age, and a greater CCT were associated with a smaller CDA (P 0.002) (n ¼ 180). In the univariate analysis (n ¼ 180), the difference between DCT and GAT measurements was associated with spherical refractive error (P ¼ 0.037), CCT (P ¼ 0.004), and CDA (P < 0.001) after adjusting the effect of IOP (DCT). In the multivariate analysis, the only factor associated with the IOP difference was CDA (P ¼ 0.003).CONCLUSIONS. CDA was a reliable indicator to quantify corneal deformation response. CDA, rather than CCT, was the key source of measurement error of GAT.Keywords: ultra-high-speed Scheimpflug camera, intraocular pressure, corneal deformation response G oldmann applanation tonometry (GAT) is the reference standard for measurement of IOP in clinical practice and clinical trials.1 Although GAT overestimates IOP in healthy eyes with thick corneas and underestimates IOP in healthy eyes with thin corneas, the corneal biomechanical response has been suggested to be more influential than central corneal thickness (CCT) in measuring IOP. 2 In a mathematical simulation model, Liu and Roberts 2 examined the association between IOP and corneal parameters, including CCT, corneal curvature, and corneal elasticity. They showed that normal variation of CCT (443-629 lm) contributed to a difference of only 2.87 mm Hg of predicted GAT IOP measurements. By contrast, variation of corneal elasticity, measured in Young's modulus with an estimated normal range between 0.1 and 0.9 MPa, accounted for a difference of 17.26 mm Hg. This is supported by an experimental study by Dupps and colleagues 3 using sonic wave propagation velocity on the corneal surface as a measure of corneal stiffness. They showed that corneal stiffening after cross-linking in two human globes resulted in a dramatic increase in IOP measured by pneumatonometer (Mentor O&O, Inc., ...

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Accuracy of dynamic contour tonometry compared with applanation tonometry in human cadaver eyes of different hydration states

Abstract: In this in vitro study DCT values for IOP were significantly closer to the manometric reference pressure than those obtained using GAT and PTG, independent of the state of corneal hydration.

Cited by 91 publications

References 28 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

Okuläre Pulsamplitude als biometrischer Messwert in der Glaukomdiagnostik

An Ultra-High-Speed Scheimpflug Camera for Evaluation of Corneal Deformation Response and Its Impact on IOP Measurement

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