Corneal endothelial cell count in keratoconus patients after contact lens wear.

PURPOSE: The influence of contact lenses on healthy corneal endothelium has been well documented, but little is known about the effect of contact lens wear on the corneal endothelial cells of patients with keratoconus. This cross-sectional comparative study was conducted to determine quantitative characteristics of corneal endothelial cells of 100 patients with keratoconus with or without contact lenses.

METHODS

A Humphrey Atlas corneal topographer was used to map the keratoconic cornea. The corneal apex of the cone was located by using the axial topography map. The Konan SP-9000 Noncon Robo Pachy specular microscope and the Konan SP-400 specular microscopes were used to photograph the endothelium at the apex of the cone, and the average endothelial cell count was obtained. Patients were categorized into four groups based on the types of contact lenses worn: no contact lenses, SofLens 66 toric contact lenses, SoftPerm contact lenses, and FluoroPerm 30 aspheric rigid gas-permeable (RGP) contact lenses. Analysis of variance was used to determine differences in endothelial cell counts among groups.

RESULTS

After controlling for age and severity of keratoconus, patients who wore SoftPerm contact lenses had 18% lower endothelial cell counts (2,157 +/- 442) than did patients without contact lenses (2,538 +/- 398). These patients also had 15% lower endothelial cell counts than did patients who wore soft toric disposable contact lenses (2,483 +/- 292). There was a 7% lower endothelial cell count in the group wearing aspheric RGP contact lenses than in the group that did not wear contact lenses, and a 5% lower endothelial cell count in the group wearing aspheric RGP contact lenses than in the group that wore soft toric contact lenses, but these differences were not statistically significant.

CONCLUSIONS

Patients with keratoconus who wear SoftPerm contact lenses have a significantly lower endothelial cell count than those patients with keratoconus who do not wear lenses, or who wear soft toric disposable contact lenses or RGP contact lenses.