Abstract

P 140

Analysis of corneal wavefront for clinical differentiation between keratoconus and pellucid marginal degeneration

Daniela-Luisa Ott, Jens Bühren, Oliver Klaproth, Thomas Kohnen
Klinik für Augenheilkunde, Klinikum der Johann Wolfgang Goethe-Universität, Frankfurt/Main

Objective
The purpose of the study is to describe differences of wavefront aberrations of the anterior and posterior corneal surface between patients with keratoconus (KC), pellucid marginal degeneration (PMD) and normal eyes.
Methods
This retrospective study included 55 eyes of 32 patients with KC, 60 eyes of 43 patients with PMD and 64 eyes of 32 patients with normal eyes.
From the axial-keratometric data of the anterior and elevation data of the posterior corneal surface we performed a Zernike decompensation (2nd – 7th order, 6mm pupil diameter). Discriminant ability of significant Zernike coefficient were assumed by receiver operating characteristic (ROC) analysis.
Results
The comparison of the anterior corneal surface between the KC group and the PMD group showed the highest discriminatory power (standardised area under the ROC curve (AzROC)) for the coefficient Z(2,2) (AzROC=0,891), between the KC group and the normal eyes for the total higher order aberration (HOA) root mean square value (AzROC=0,971) and between the PMD group and normal eyes for the coefficient Z(3,-1) (AzROC=0,991).
For the posterior corneal surface Z(3,-1) (AzROC=0,816), residual HOA root mean square value (AzROC=0,967) and residual HOA root mean square value (AzROC=0,963) were found by discriminative ability. Residual HOA means non coma, non spherical.
Conclusions
Zernike coefficients from the anterior and posterior corneal surface could be used as parameters to discriminate between normal, KC and PMD eyes.

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