Changes in Refraction, Ocular Aberrations, and Corneal Structure After Suspending Rigid Gas-Permeable Contact Lens Wear in Keratoconus

Purpose: This study reports on changes in visual acuity, ocular higher-order aberrations, and refraction after suspending rigid gas-permeable lens wear for 1 week in 15 patients with moderate to severe keratoconus. Alterations in the anterior surface, central corneal powers and axes, and central corneal thickness were also explored. Methods: Scheimpflug photography and Hartmann-Shack aberrometry were performed at 2 visits, 7 days apart, after the patients had removed their habitual contact lenses. Subjective refraction and both high-and low-contrast logarithm of the minimum angle of resolution visual acuities were also recorded at both visits. Results: Reductions in both high-contrast visual acuity (P = 0.001) and low-contrast visual acuity (P = 0.002), along with an increase in third-order root mean square aberrations (P = 0.008), occurred after rigid gas-permeable lens wear was suspended in these patients with keratoconus. However, no significant changes in subjective refraction were found over the 1-week period (P >= 0.10). Significant correlations were observed between third-order coma root mean square aberrations and the measured high-contrast (r(p) > 0.59; P < 0.02) and low-contrast visual acuities (r(P) >= 0.61; P <= 0.015). In addition to increases in the anterior surface central corneal powers (P <= 0.02), a reduction in central corneal thickness also was found between the 2 visits (P = 0.00016). Conclusions: Changes in the optical and structural parameters of the keratoconic cornea occur after suspending rigid gas-permeable contact lens wear. This information may be of interest to practitioners concerned with prescribing aberration-controlling soft contact lenses for such patients.