Corneal Higher-Order Aberrations after Crosslinking and Intracorneal Ring Segments for Keratoconus.

PURPOSE: To assess anterior corneal higher-order aberrations (HOAs) after corneal crosslinking (CXL) and intracorneal ring segments (Intacs) used adjunctively. SETTING: Cornea and refractive surgery practice. DESIGN: Prospective, randomized clinical trial. METHODS: For this study, 158 eyes were randomized to 2 groups: concurrent, Intacs and CXL during the same session (n=81), or sequential, Intacs followed by CXL 3 months later (n=77). Outcomes included changes in total, coma, trefoil, and spherical anterior corneal HOA 6 months after Intacs/CXL. The change in anterior corneal HOAs was correlated with the change in uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and topography indices of maximum keratometry (Kmax), maximum flattening keratometry (Kmaxflat), and inferior-superior (I-S) ratio. A subjective visual function questionnaire was also analyzed. RESULTS: UDVA, CDVA, Kmax, I-S , and Kmaxflat all improved 6 months after treatment (UDVA = -0.22 +/- 0.34, p<0.001), CDVA = -0.13+/-0.24, p<0.001, Kmax = -3.1+/-3.0D, p<0.001, I-S = -4.2+/-5.0 diopter [D], p<0.001, Kmaxflat = -7.9+/-4.0 D, p<0.001). Total anterior corneal HOA, vertical coma, and horizontal coma anterior corneal HOAs, significantly improved by -1.05+/-0.93 microm (p<0.001), -1.53+/-1.18 microm (p<0.001), and -0.35+/-0.57 microm (p<0.001), respectively. Spherical anterior corneal HOAs increased by 0.24+/-0.70 microm (p<0.001), 6 months after Intacs/CXL. The change in trefoil was not statistically significant (ptrefoil0=0.06,ptrefoil30=0.2). There were no significant differences between the changes in anterior corneal HOAs in the sequential and same-day Intacs/CXL groups. The change in total anterior corneal HOAs was correlated with Kmax, Kmaxflat, and the I-S ratio. There was no correlation between the change in anterior corneal HOAs and the change in visual acuity or visual function survey responses. CONCLUSIONS: Total, horizontal coma, and vertical coma anterior corneal HOAs improved after Intacs/CXL. Spherical anterior corneal HOAx increased postoperatively, and there was no change in trefoil after surgery. Improvement of anterior corneal HOAs did not correlate with visual acuity improvement or subjective visual satisfaction outcomes.