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S. Bardanzellu, F. Oddone, M. Centofanti, A. Tosto, L. Tanga, P. Fogagnolo, M. Figus, G. Manni; Reproducibility of Corneal Biomechanical Responses and Intraocular Pressure Measurements Performed by the Reichert Ocular Response Analyser. Invest. Ophthalmol. Vis. Sci. 2008;49(13):716.
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© ARVO (1962-2015); The Authors (2016-present)
The Reichert Ocular Response Analyser (ORA, Reichert ophthalmic instruments, Buffalo, NY) is a modified non-contact tonometer that allows individual quantification of corneal biomechanical properties such as corneal hysteresis (CH) and corneal resistance factor (CRF) and allows to correct for them to obtain more accurate intracocular pressure readings (IOPcc). The aim of this study was to evaluate the reproducibility of CH, CRF, and IOPcc measurements in normal eyes and to compare the latter with that of Goldmann applanation tonometry (GAT).
This was a cross-sectional study on 92 eyes of 92 healthy subjects (age 41.86±17.2 yrs, 54 females, 38 males). Beside a complete ophthalmological evaluation axial length, anterior chamber depth, refractive error, corneal curvature, and central corneal thickness (CCT) were taken. Three GAT readings were recorded and 3 groups of CH, CRF and IOPcc measurements, each of three readings, were obtained by ORA, and the average of each group was used for statistical analysis. The reproducibility of measurements was quantified by coefficient of variation (CV) and compared between instruments by Wilcoxon Sign-Rank test.
The mean of IOPcc average readings were 17.0±3.8, 16.3±3.3 and 15.9±3.2 mmHg with a CV of 7.5±3.8. Mean GAT readings were 13.0±2.6, 12.6±2.7, and12.5±2.8 mmHg with a CV of 4.39±3.9. The difference between IOPcc and GAT CVs was statistically significant (p<0.01). Mean CH average readings were 10.4±1.8, 10.6±1.6, and 10.7±1.8 mmHg, with a CV of 5.9±3.6. Mean CRF average readings were 10.8±1.9, 10.7±1.9, and 10.7±1.96, with a CV of 4.9±3.0.
Corneal biomechanical responses measured by ORA are highly reproducible. ORA corrected IOP measurements showed a good reproducibility although lower than that of GAT measurements in healthy subjects.
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