Comparison of long-term outcomes of simultaneous accelerated corneal crosslinking combined with intracorneal ring segment or topography-guided PRK

Purpose: To compare long term outcomes of simultaneous accelerated corneal cross-linking (CXL) with intrastromal corneal ring segments (CXL-ICRS) to simultaneous accelerated CXL with topography-guided photorefractive keratectomy (CXL-TG-PRK) in progressive keratoconus. Setting: The Kensington Eye Institute and Bochner Eye Institute, Toronto, Canada. Design: Prospective non-randomized interventional study. Methods: The change in visual and topographical outcomes of CXL-ICRS and CXL-TG PRK 4-5 years after surgery were compared using linear regression models adjusting for preoperative corrected distance visual acuity (CDVA) and maximum keratometry (Kmax). Results: Fifty-seven eyes of 43 subjects with progressive keratoconus that underwent simultaneous accelerated (9 mW/cm2, 10 minutes) CXL-ICRS (n=32) and CXL-TG-PRK (n=25) were included. Mean follow-up duration was 51.28 (9.58) and 54.57 (5.81) months for the CXL-ICRS and CXL-TG-PRK groups, respectively. Initial mean Kmax was higher in the CXL-ICRS compared to CXL-TG-PRK group (60.68±6.81D VS 57.15±4.19D, p=0.02). At last follow-up, change (improvement) in logMAR uncorrected distance visual acuity (UDVA) compared to pre operatively was significant with CXL-ICRS (-0.31±0.27, p<0.001 which is equivalent to approximately 3 lines) and not significant with CXL-TG-PRK (-0.06±0.42, p=0.43). The logMAR CDVA improved significantly with CXL-ICRS (-0.22±0.20, p<0.001) but not with CXL-TG-PRK (-0.05±0.22, p=0.25). Adjusting for baseline Kmax and CDVA, the improvement in UDVA was significantly greater with CXL-ICRS than with CXL-TG-PRK (-0.27 [95% CI, 0.06 to 0.47, P = 0.01]). Improvement in CDVA was not significantly different. Conclusion: In this cohort of progressive keratoconus with long term follow up UDVA showed more improvement with accelerated CXL-ICRS than with CXL-TG-PRK.