Effects of Multicurve RGP Contact Lens Use on Topographic Changes in Keratoconus

PURPOSE To evaluate the effects of wearing rigid gas permeable (RGP) contact lenses on the topographic changes in keratoconus. METHODS Seventy-seven keratoconic eyes that wore multicurve RGP contact lenses and 30 keratoconic eyes that wore no contact lenses were retrospectively analyzed. The mean follow-ups were 22.6 and 20.5 months in the lens-wearing and control groups, respectively. Visual acuity, comfort, daily wearing time, and corneal staining were evaluated for both groups. The changes in topographic indices were compared between the lens-wearing and control groups. RESULTS Multicurve RGP lens corrected logarithm of the minimum angle of resolution visual acuity of the lens-wearing group significantly improved from -0.016+/-0.065 to -0.032+/-0.10 at follow-up (p=0.05). In the lens-wearing group with advanced keratoconus, the Sim Kmax, Sim Kmin, apical power, astigmatic index, and anterior elevation significantly decreased from 57.68+/-4.26 diopter (D), 50.50+/-2.32 D, 62.79+/-5.11 D, 7.20+/-0.55 D and 67.36+/-16.30 microm to 55.51+/-4.28 D, 49.62+/-3.26 D, 60.31+/-5.41 D, 5.90+/-0.51 D and 60.61+/-16.09 microm, respectively (paired t-test, p<0.05). The irregularity index of 3 mm did not significantly change. Meanwhile, in the control group, the apical power and irregularity index increased from 55.56+/-7.25 D and 3.06+/-1.68 D to 57.11+/-7.75 D and 3.25+/-1.71 D, respectively (paired t-test, p=0.008, p=0.01). CONCLUSIONS Properly fitted multicurve RGP contact lenses are not likely to contribute to the progression of keratoconus.