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T. Dada, S. Bhartiya, M. James, V. Dave, A. Panda, R. M. Pandey; Test Retest Variability of Iop Measurements Using Tonopen Avia. Invest. Ophthalmol. Vis. Sci. 2009;50(13):2851.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the repeatability of the tonometric recordings of the Tonopen Avia (TPA) and compare it with IOP recordings done with Goldmann Applanation Tonometer (GAT) and non contact tonometer (NCT) .
This prospective, observational, comparative case series consisted of 140 eyes of 140 patients with an age related cataract. NCT was performed first, followed by GAT and TonoPen Avia measurement after a 10 min break. The TPA readings were repeated twice in succession at 5 minute intervals. Patients with any corneal pathology or previous refractive surgery were excluded from this study.
The mean age of patients enrolled in the study was 44.2 ± 16.6 years (range 25 to 75 years). The mean IOP measured by NCT and GAT was 16.2 ± 5.1 and 15.8 ± 4.1 mmHg respectively. The mean IOP recorded with TPA were 15.6 ± 4.2, 15.4 ± 4.3 and 15.6 ± 4.3 mm Hg, respectively in the first, second and third instances. The reliability analysis showed good repeatability of the IOP measurement using TPA (Intraclass Correlation Coefficient =0.87 and repeatability coefficient = 2.37). The coefficient of variation for these intersession IOP recordings was 16.32. The mean difference between TPA and NCT was 0.6 (with 95% limits of agreement between -5.1 and 6.3 mmHg). The mean difference for TPA and GAT was 0.2 (with 95% limits of agreement between -5.2 and 5.7 mmHg) while that between GAT and NCT was 0.39 (-7.2 and 6.4 mmHg) respectively. The Karl Pearsons correlation coefficient between GAT and TPA, NCT and GAT, and TPA and NCT was statistically significant (0.768, 0.737 and 0.821 respectively, p<0.01) .
The Tonopen Avia shows a good intersessional repeatability of IOP and correlates well with both GAT and NCT.
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