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Research Journal of Medical Sciences

ISSN: Online 1993-6095
ISSN: Print 1815-9346
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Comparative Accuracy of Intra Ocular Pressure Measurement in Thin Corneas: Non‐Contact, Applanation and Schiotz Tonometry

R. Rinita, S. Veeralakshmanan, Biju Gopal, R. Hannah Shiny and S.A. Arsha Ressal
Page: 148-153 | Received 28 Apr 2024, Published online: 11 Jun 2024

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https://doi.org/10.36478/10.36478/makrjms.2024.7.148.153

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Abstract

Intra ocular pressure (IOP) measurement is essential for diagnosing and managing glaucoma. Accurate IOP measurement is particularly challenging in patients with thin corneas, as corneal thickness influences the accuracy of various tonometry methods. This study compares the accuracy and reliability of non‐contact tonometry (NCT), Goldmann applanation tonometry (GAT) and Schiotz tonometry (ST) in individuals with thin corneas. This cross‐sectional study included 100 participants (50 males, 50 females) aged 18‐70 years with central corneal thickness (CCT) <500 μm. IOP measurements were taken using NCT, GAT and ST in a randomized sequence. Each method's reproducibility and agreement with GAT were assessed using descriptive statistics, correlation analysis, Bland‐Altman analysis, and intra‐class correlation coefficients (ICC). The mean IOP values were 15.2±2.5 mmHg for NCT, 14.8±2.3 mmHg for GAT, and 16.1±2.7 mmHg for ST. NCT and ST showed strong correlations with GAT (r = 0.88 and 0.82, respectively). Bland‐Altman analysis revealed mean differences of 0.4 mmHg (NCT vs. GAT) and 1.3 mmHg (ST vs. GAT). The 95% limits of agreement were‐3.5‐4.3 mmHg (NCT vs. GAT) and‐4.2 to 6.8 mmHg (ST vs. GAT). ICC values were 0.94 (GAT), 0.92 (NCT) and 0.89 (ST). NCT had 85% of measurements within±2 mmHg of GAT, while ST had 70%. Non‐contact tonometry demonstrated strong agreement and high reproducibility with applanation tonometry, making it a reliable alternative for measuring IOP in individuals with thin corneas. Schiotz tonometry, despite good correlation with GAT, showed lower precision and reproducibility. Applanation tonometry remains the gold standard for accurate IOP measurement, even in thin corneas. Further studies with larger, more diverse populations are recommended to validate these findings.

How to cite this article:

R. Rinita, S. Veeralakshmanan, Biju Gopal, R. Hannah Shiny and S.A. Arsha Ressal. Comparative Accuracy of Intra Ocular Pressure Measurement in Thin Corneas: Non‐Contact, Applanation and Schiotz Tonometry.
DOI: https://doi.org/10.36478/10.36478/makrjms.2024.7.148.153
URL: https://www.makhillpublications.co/view-article/1815-9346/10.36478/makrjms.2024.7.148.153