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Evaluation of dual Scheimpflug imaging parameters in eyes with forme fruste keratoconus, keratoconus, and low and high ametropia
Session Title: Imaging II
Session Date/Time: Monday 07/10/2013 | 16:30-18:00
Paper Time: 16:54
Venue: Main Lecture Hall (Ground Floor)
First Author: : M.Henriquez PERU
Co Author(s): : L. Izquierdo Jr H. Moreyra
To evaluate the efficacy of several parameters obtained from Dual Scheimpflug Analyzer to discriminate between forme fruste keratoconus, keratoconus and low and high ametropia.
Oftalmosalud Instituto de Ojos, Lima, Peru
This prospective study included 382 eyes (100 eyes with low ametropia, 50 with high cylinder, 29 with high myopia, 41 forme fruste keratoconus and 162 keratoconus). Scheimpflug imaging using the Galilei Dual Scheimpflug Analyzer (Ziemer) was performed and several parameters derived from pachymetry, curvature, anterior and posterior elevation maps, corneal wavefront high order aberrations, and others was recorded. Receiver operating characteristic curves (ROC) was used and logistic regression analysis was used to evaluate the sensitivity and specificity of the parameters in a constructed model.
There were statistically significant difference between low ametropic eyes and high cylinder group in the anterior and posterior elevation at the thinnest point of the cornea (p < 0.001 both). There were not statistically significant differences between the low ametropic eye and high myopic group in pachymetric and elevation variables (p > .05). Logistic regression analysis showed that a combination of corneal power, thickness, elevation, and corneal aberrations had a 100% sensitivity and specificity discriminating between low ametropic eyes and keratoconus.
Combined analysis of anterior and posterior corneal power, thickness, elevation and corneal aberrations effectively discriminated between ectatic corneas and normal corneas. High astigmatism group showed greater posterior elevation values than high myopic group and eyes with low refraction.