Relation between corneal thickness and intraocular pressure measurement by noncontact and applanation tonometry

Recep, Ömer Faruk; Hasıripi, Hikmet; Çağıl, Nurullah; Sarikatipoğlu, Hikmet

doi:10.1016/s0886-3350(01)00900-2

Cited by 62 publications

(48 citation statements)

References 18 publications

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“…Another study reported a significant intraindividual difference between the NCT (Topcon CT60) and GAT measurements in 60 glaucoma patients (120 eyes). 16 The difference was positively correlated with CCT in eyes with a corneal thickness greater than 574.5 mm. This indicates that the CCT-induced overestimation is greater with the NCT than that with the GAT in eyes with a thick cornea.…”

Section: Discussionmentioning

confidence: 87%

Varying Effects of Corneal Thickness on Intraocular Pressure Measurements with Different Tonometers

Liu

Hsu

2004

Eye

111

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Aims To compare the intraocular pressure (IOP) measurements using the Goldmann applanation tonometer (GAT), noncontact tonometer (NCT), and ocular blood flow tonometer (OBFT), and to evaluate the effects of varying central corneal thickness (CCT) on the readings. Methods Ultrasound pachymetry and tonometry were performed on 170 eyes. Using the corrected GAT values that took CCT into account as the standard, we calculated the NCT and OBFT measurement errors related to the CCT variable by a linear regression model. Group comparisons were performed with the v 2 test and one-way ANOVA test. The correlation between the various tonometer measurements was analysed by Pearson's correlation method. Results Both the NCT (r ¼ 0.872, Po0.001) and OBFT measurements (r ¼ 0.861, Po0.001) were highly correlated with the GAT measurements. IOP measurements using the three tonometers were all correlated with CCT (all Po0.001), with the NCT measurements showing the greatest regression coefficient (b ¼ 0.063, r ¼ 0.650) and the GAT measurements the least (b ¼ 0.037, r ¼ 0.496). A linear regression model indicated that a 10 lm change in CCT resulted in a NCT measurement deviation of 0.47-0.98 mmHg and an OBFT measurement deviation of 0.29-0.81 mmHg.Conclusion Pressure readings with the GAT, NCT, and OBFT are all affected by CCT, with the NCT being the one most affected and the GAT the least. Our findings suggest CCT an essential variable to consider in interpreting IOP readings, especially for the NCT measurements.

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Section: Discussionmentioning

confidence: 87%

Varying Effects of Corneal Thickness on Intraocular Pressure Measurements with Different Tonometers

Liu

Hsu

2004

Eye

111

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“…The NCT is estimated to exhibit a deviation of 0.10 mm Hg from the GAT for every 10-µm increase in CCT. Previous studies have reported a deviation of 0.22-0.98 mm Hg for a similar change of CCT [22,23,24]. There is a significant controversy regarding the influence of CCT on IRT measurements compared to the GAT.…”

Section: Discussionmentioning

confidence: 98%

Comparability of Icare Pro Rebound Tonometer with Goldmann Applanation and Noncontact Tonometer in a Wide Range of Intraocular Pressure and Central Corneal Thickness

et al. 2015

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Purpose: To evaluate the agreement between the reading values of the Goldmann applanation tonometer (GAT), Icare Pro rebound tonometer (IRT) and noncontact tonometer (NCT) in glaucoma patients. Methods: This cross-sectional study comprised 292 eyes of 292 patients selected from a glaucoma outpatient clinic. The intraocular pressure (IOP) was measured sequentially, at a 10-min interval each, in the following order: NCT, IRT and GAT. The central corneal thickness (CCT) was measured using Pentacam HR before the IOP measurements. Results: The mean IOPs measured by the GAT, NCT and IRT were 20.17 ± 6.73 mm Hg (range: 4-48), 19.77 ± 6.88 mm Hg (range: 3-46) and 19.30 ± 5.15 mm Hg (range: 7.30-44.5), respectively. The correlation coefficients of the GAT and IRT, NCT and IRT, and GAT and NCT measurements were r² = 0.673, r² = 0.663 and r² = 0.938 (all p < 0.001), respectively. The IRT tends to overestimate in the low GAT-measured IOPs, whereas it underestimates in high GAT-measured IOPs. The measurements of all 3 devices were also correlated with the CCT at a statistically significant level (GAT: r² = 0.063, NCT: r² = 0.063, IRT: r² = 0.058). Conclusion: The agreement between the IRT and GAT measurements is higher in the IOP range of 9-22 mm Hg, whereas significant discrepancies occur as the IOP deviates from normal values. The variability of the IRT and GAT measurements over a wide range of CCT is minimal.

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“…Whether these factors had been balanced between the cohorts were not mentioned in the parallel-designed RCTs in this meta-analysis. The Perkins applanation tonometry provides the same accuracy as GAT, while noncontact tonometry (NCT) will be less accurate [49]. These measurement errors might interfere with the validity of the results and contribute to the variety of the effects measured by different studies, although the analysis result was not biased by omitting the data measured by NCT.…”

Section: Discussionmentioning

confidence: 99%

The effect of caffeine on intraocular pressure: a systematic review and meta-analysis

Wang

Guo

et al. 2010

Graefes Arch Clin Exp Ophthalmol

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Relation between corneal thickness and intraocular pressure measurement by noncontact and applanation tonometry

Abstract: The reliability of tonometers decreased with increasing corneal thickness, in which case higher readings were found, especially with the noncontact tonometer.

Cited by 62 publications

References 18 publications

Varying Effects of Corneal Thickness on Intraocular Pressure Measurements with Different Tonometers

Varying Effects of Corneal Thickness on Intraocular Pressure Measurements with Different Tonometers

Comparability of Icare Pro Rebound Tonometer with Goldmann Applanation and Noncontact Tonometer in a Wide Range of Intraocular Pressure and Central Corneal Thickness

The effect of caffeine on intraocular pressure: a systematic review and meta-analysis

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