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Correlation of Corneal Endothelial Changes With Different Stages of Keratoconus

El-Agha, Mohamed-Sameh H. MD; El Sayed, Yasmine M. MD; Harhara, Rana M. MBBCh; Essam, Hamdy M. MD

doi: 10.1097/ICO.0000000000000134
Clinical Science

Purpose: The aim was to study the corneal endothelial count and morphology in patients with keratoconus by specular microscopy and to correlate them to the stage of keratoconus.

Methods: Forty eyes of 29 patients with keratoconus were enrolled in this cross-sectional cohort study. Corneal endothelium was evaluated using specular microscopy, and corneal topography and thickness data were obtained from Scheimpflug-based corneal tomography. Eyes were classified into stages 1 through 4 of keratoconus according to Amsler classification, using keratometry and pachymetry readings obtained from corneal tomography.

Results: Eleven eyes (27.5%) had stage 1, 17 eyes (42.5%) had stage 2, and 12 eyes (30%) had stage 3. Specular microscopy was not possible in stage 4. There was no statistically significant correlation between the stage of keratoconus and the endothelial cell density (ECD) (r = 0.018, P = 0.91), coefficient of variation (CV) (r = −0.011, P = 0.94), or percentage of hexagonality (6A) (r = −0.112, P = 0.51). When mild-to-moderate keratoconus (stages 1 and 2) was compared with severe keratoconus (stage 3), the difference was not significant regarding ECD (P = 0.1), CV (P = 0.3), or 6A (P = 0.4). However, there was a trend toward lower ECD and percentage of hexagonality, and a higher CV with advancing disease.

Conclusions: Up to stage 3, keratoconus does not significantly affect the corneal endothelium, as measured by specular microscopy. Eyes with stage 4 could not be studied by specular microscopy and may require other imaging methods such as confocal microscopy.

Author Information

Ophthalmology Department, Cairo University Faculty of Medicine, Cairo, Egypt.

Reprints: Yasmine M. El Sayed, Cairo University Faculty of Medicine, 9 Ahmed Samy El Sayed Square, Cairo 12311, Egypt (e-mail:

The authors have no funding or conflicts of interest to disclose.

Received January 02, 2014

Accepted March 18, 2014

© 2014 by Lippincott Williams & Wilkins.