Effect of treatment sequence in combined intrastromal corneal rings and corneal collagen crosslinking for keratoconus

PURPOSE: To compare 2 sequences of combined intrastromal corneal ring segment (ICRS) implantation and ultraviolet/riboflavin-mediated corneal collagen crosslinking (CXL) in progressive keratoconus. SETTING: Dunya Eye Hospital, Istanbul, Turkey. METHODS: In this prospective comparative randomized consecutive study, CXL was followed by ICRS implantation (Group 1) or ICRS implantation was followed by CXL (Group 2). Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, spherical equivalent (SE), manifest cylinder (cylinder), and mean keratometry (K) were compared preoperatively and postoperatively. RESULTS: The mean interval between treatments was 7 months +/- 2 (SD) (mean follow-up, 13 +/- 1 months). The mean UDVA and CDVA improved in both groups (UDVA: 0.07 +/- 0.09 to 0.25 +/- 0.12, Group 1, and 0.11 +/- 0.09 to 0.32 +/- 0.21, Group 2; CDVA: 0.24 +/- 0.11 to 0.41 +/- 0.20 and 0.22 +/- 0.16 to 0.55 +/- 0.2, respectively). The mean SE, cylinder, and mean K values decreased in both groups (SE: -7.13 +/- 3.34 D to -2.98 +/- 2.33 D, Group 1, and -7.05 +/- 5.54 D to -2.81 +/- 4.08 D, Group 2; cylinder: -4.38 +/- 2.03 D to -2.62 +/- 1.93 D and -4.68 +- 2.60 D to -2.20 +/- 1.67 D, respectively; mean K: 52.47 +/- 4.01 D to 48.31 +/- 3.65 D and 52.06 +/- 4.93 D to 48.08 +/- 4.13 D, respectively). Overall, there was more improvement in CDVA, SE, and mean K in Group 2 than in Group 1. CONCLUSION: Implantation of ICRS followed by CXL resulted in greater improvement of keratoconus.