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J.T. Schwiegerling, R.W. Snyder, G. Steward; Comparing Corneal Topography from the Oculus Pentacam and the Humphrey Atlas . Invest. Ophthalmol. Vis. Sci. 2006;47(13):2955.
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© ARVO (1962-2015); The Authors (2016-present)
To compare the repeatability and correlation between measurements of the anterior corneal surface captured with the Oculus Pentacam Scheimpflug imager and the Humphrey Atlas corneal topographer
Four consecutive measurements of 14 subjects were captured with both devices. Elevation data was exported and analyzed to extract the radii of curvature of the anterior cornea along the principal meridia. Repeatability of the devices was assessed by examining the standard deviation of the repeated measures. Correlation of the radii of curvature along the principal meridia between the two devices was also explored.
Both devices are highly repeatable, with an average standard deviation in the radii of curvature measurement of 41 microns for the Pentacam and 48 microns for the Atlas. The radii measurements are highly correlated between the devices with R2 = 0.80. However, a t–test shows the measurements to have significantly different means (p = 0.00002). In general, the Pentacam gives a longer radii of curvature when compared to the Atlas.
Both the Oculus Pentacam and the Humphrey Atlas provide highly repeatable measures of the cornea. While these measures are correlated, there are some differences between the predicted shapes. The accuracy of the Atlas has been previous assessed with static surfaces of known shape. Similar studies with the Pentacam should be performed as well. In addition, the two devices may center their exams at slightly different points. Alignment of the exams will be explored in future work.
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