Effect of the Aspheric RGP Lens on Corneal Topography and Endothelial Cell in Keratoconus

ABSTRACT

PURPOSE: To analyze the effects of the aspheric rigid gas permeable (RGP) lens on the corneal topography and endothelial cells in eyes with keratoconus. METHODS: Sixty five eyes of 35 keratoconic patients who had follow-up of more than 6 months were included in the study. Thirty eyes of 16 patients wore aspheric RGP lens, and the remaining control eyes did not wear any lens. After aspheric RGP lens fitting, visual acuity and manifest refractive error were evaluated, Slit lamp examination and corneal topography were also done. Mean cell area and density of corneal endothelial cell were measured by specular microscopy at first visit and 6 months after lens fitting. RESULTS: After lens fitting, the percentage of best corrected visual acuity of better than 20/25 was 93.3% (28 eyes). The change of astigmatism, the Steepest Simulated keratometry reading, Surface asymmetry index, Surface regularity index, and apical corneal power were significantly increased in the keratoconic cornea in aspheric lens fitting group compared to the control group (p0.05). CONCLUSIONS: Short-term wearing of aspheric RGP lens in keratoconic patients showed no effect on corneal endothelial cells. However, it increased the irregularity and steepening of the keratoconic cornea. It may indicate that mid-peripheral corneal-to-lens relationship may be inappropriate when keratoconus is fitted with aspheric lens.