Myoring implantation alone versus corneal collagen cross-linking following myoring implantation for management of keratoconus: 1 year follow up

Purpose: To compare combined MyoRing implantation with previously corneal collagen cross-linking (CXL- MyoRing) versus MyoRing implantation alone in patients with keratoconus. Methods: This retrospective, comparative, cohort study included 33 eyes of 33 patients with keratoconus stage II and III according to Amsler-Krumeich classification. Two groups were performed for this study with 1 year follow up. The group 1 received MyoRing implantation and the group 2 received CXL approximately 12 months before MyoRing implantation. All patients had a complete pre and post-operative examination including visual, refractive and keratometry examinations. Results: In Group 1 at the end of follow up the mean UDVA and CDVA improved by 9 and 4 lines of logMAR. In Group 2 the mean UDVA and CDVA improved by 8 and 2 lines of logMAR. There was not observed a statistically significant difference between mean UDVA of two groups postoperatively (p = 0.142) whereas the mean CDVA in Group 2 was significantly better than mean Group 1 at the end of follow up (p= 0.018). Spherical equivalent error and refractive astigmatism were significantly reduced in both groups which no statistically significant differences was noted in these refractive parameters between two groups. The mean keratometric values also were reduced in both groups at the end of follow up which no statistically significant difference was observed between two groups. Conclusion: Both MyoRing implantation alone and combined MyoRing implantation with previously CXL were safe and effective methods for moderate and severe keratoconus and resulted in similar clinical outcomes after one year follow up. ExclusivelyMyoRing implantation alone demonstrated better outcome in mean CDVA.