Mesopic visual quality after accelerated corneal cross linking: A 12-month follow-up study

Purpose: To determine the 1-year changes of mesopic higher order aberrations (HOAs) and contrast sensitivity (CS) after accelerated corneal cross linking (CXL) in progressive keratoconus. Methods: In this prospective case series, 70 eyes of 62 keratoconic patients underwent accelerated CXL (18 mW/cm2, 5 min). HOAs and CS were measured using the OPD Scan III and CSV-1000 CS test charts under mesopic conditions before and 6 and 12 months after CXL. Results: At 1 year, logarithmic mesopic CS in spatial frequencies of 3, 6, 12, and 18 cycles per degree (CPD) had increased by 0.05 ± 0.29 (P ¼ 0.029), 0.04 ± 0.88 (P ¼ 0.012), 0.27 ± 0.46 (P ¼ 0.172), and 0.06 ± 0.22 (P ¼ 0.020), respectively. The decrease in ocular HOAs (0.10 ± 0.69 mm, P ¼ 0.992) [coma (0.08 ± 1.01 mm, P ¼ 0.613), trefoil (0.03 ± 0.37 mm, P ¼ 0.659), and spherical aberration (SA) (0.10 ± 0.59 mm, P ¼ 0.743)] and corneal HOAs (0.40 ± 1.69 mm, P ¼ 0.874) [coma (0.39 ± 1.59 mm, P ¼ 0.401), trefoil (0.33 ± 2.16 mm, P ¼ 0.368), and SA (1.27 ± 1.14 mm, P ¼ 0.354)] were not statistically significant. The correlations between mesopic CS and HOAs were weak before and after CXL. Conclusion: One year after accelerated CXL, CS significantly improved, but changes in HOAs were statistically insignificant. CS changes were independent of HOAs.