Accuracy and precision of keratometry, photokeratoscopy, and corneal modeling on calibrated steel balls
S. B. Hannush, S. L. Crawford, G. O. Waring 3rd, M. C. Gemmill, M. J. Lynn and A. Nizam
Department of Ophthalmology, Emory University School of Medicine, Atlanta, GA.
Surgical manipulation of corneal shape requires an accurate and precise
method of measuring anterior corneal curvature from apex to limbus. We
evaluated the accuracy and precision of the Bausch & Lomb Keratometer,
Kera Corneascope, and Computed Anatomy Corneal Modeling System by measuring
comparable locations on four calibrated steel test balls. The Keratometer
and Corneal Modeling System were more accurate and precise than the
Corneascope. No statistically significant difference was found between the
Keratometer and Corneal Modeling System with respect to accuracy or
precision. In addition, the accuracy and precision of all 31 rings of the
Corneal Modeling System were studied. Rings 2 through 26 were read
accurately and precisely within +/- 0.25 diopter on three of the four
balls. Values on the steepest ball were within +/- 0.37 diopter.
