The Influence of Corneal Density and Thickness on Tonometry Measurement with Goldmann Applanation, Non-contact and ICare Tonometry Methods

Overview

Journal Int Ophthalmol

Specialty Ophthalmology

Date 2022 Jan 13

PMID 35023013

Authors

Ahmed Lubbad

Irene Oluwatoba-Popoola

Melanie Haar

Carsten Framme

Anna Bajor

Affiliations

Soon will be listed here.

Abstract

Purpose: To evaluate the effect of corneal density and thickness on the accuracy of tonometry readings obtained via three most used techniques.

Method: Intraocular pressures of 45 patients' right eyes were measured using Goldmann Applanation, iCare, and non-contact tonometry methods. Corneal parameters were obtained using the Pentacam Camera System. Data obtained were analyzed using Paired t Test, Pearson's correlation coefficient, multiple linear regression analysis, and Bland-Altman plots.

Results: The mean corneal thickness was 545.4 ± 3.93 μm. The mean corneal density of total, stromal, 0-2 mm, and 2-6 mm zones were 27.85 ± 6.23 GSU, 24.61 ± 6.05 GSU, 20.76 ± 2.96 GSU, and 20.81 ± 3.51 GSU respectively. IOP readings had a statistically significant correlation with corneal stromal thickness, as well as with total and stromal density. The stromal density, however, showed higher correlation with the three tonometry methods than did the total density (iCare: - .482 (0.001) stromal density versus- .464 (0.001) total density, NCT: - .376 (0.011) versus - .353 (0.017), GAT: - .306 (0.041) versus - .296 (0.048)). Statistical differences were found in comparing the iCare readings with GAT (P < 0,00) and with NCT (P < 0,00), with mean differences of 1.8 mmHg ± 2.6 and 2.0 mmHg ± 2.6 respectively. GAT and NCT measurements showed no statistical difference (P > 0.05).

Conclusion: This study shows that both central corneal thickness and stromal density are significant influential factors of reliable IOP readings. It is necessary to consider more corneal biomechanical properties, as well as exercise a high degree of caution in any new attempts towards adjusting an IOP-correction equation.

Citing Articles

Impacts and Correlations on Corneal Biomechanics, Corneal Optical Density and Intraocular Pressure after Cataract Surgery.

Lin F, Ho R, Yu H, Yang I, Fang P, Kuo M Diagnostics (Basel). 2024; 14(14).

PMID: 39061693 PMC: 11275892. DOI: 10.3390/diagnostics14141557.

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