. 2018; 48(3): 99-108

Evaluation of scheimpflug tomography parameters in subclinical keratoconus, keratoconus and normal caucasian eyes

Samira Huseynli, Farah Abdulaliyeva
National Ophthalmology Center named after academican Zarifa Aliyeva, Baku, Azerbaijan

Purpose: To evaluate tomographic and topographic parameters in subclinical and clinical keratoconus eyes by comparing them with normal eyes in young Caucasian population.
Methods: This is a cross - sectional study included 88 normal eyes (control group), bilateral data from preclinical stage of 24 progressive keratoconus eyes (bilateral subclinical keratoconus group), 40 fellow eyes of patients with unilateral keratoconus (fellow eyes group) and 97 mild stages of keratoconus eyes. Topographic and tomographic data, data from enhanced elevation maps and keratoconus indices, were measured in all study eyes using the Scheimpflug tomography. Receiver operating characteristic (ROC) analysis was used to assess individual parameters to discriminate eyes of patients with subclinical and clinical keratoconus from control eyes. The sensitivity and specificity of the mean effective parameters were evaluated and optimal cutoff points were identified to differentiate subclinical keratoconus and keratoconus from normal corneas.
Results: While comparing all subclinical and clinical KC eyes from normal group, most of diagnostic parameters showed significant differences. The ROC curve analysis showed high overall predictive accuracy of several Pentacam parameters, such as overall D value, anterior and posterior elevations and difference elevations, pachymetry progression index, index of surface variance, index of height decentration and keratoconus index in discriminating ectatic corneas from normal ones and this outcomes were proportionally less pronounced in all subclinical keratoconus eyes than in clinical keratoconus eyes. Pachymetric readings were progressively lower in bilateral subclinical keratoconus eyes group and sensitivity and specificity of the analyzed tomographic and topographic parameters were higher than fellow eyes group when differentiating subclinical keratoconus from healthy corneas.
Conclusion: The Sheimpflug tomography parameters, such as D value, elevation parameters, progression index and several surface indices can effectively differentiate keratoconus from normal corneas in Caucasian population. Still a combination of different data is required to distinguish subclinical keratoconus.

Keywords: Subclinical keratoconus, keratokonus, Scheimpflug tomography, Pentacam


Samira Huseynli, Farah Abdulaliyeva. Evaluation of scheimpflug tomography parameters in subclinical keratoconus, keratoconus and normal caucasian eyes. . 2018; 48(3): 99-108

Corresponding Author: Samira Huseynli, Azerbaijan


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