Standard cross‐linking versus photorefractive keratectomy combined with accelerated cross‐linking for keratoconus management: a comparative study

Abstract

Purpose To compare the safety and efficacy of standard 30 min epithelium‐off cross‐linking ( CXL ) versus photorefractive keratectomy ( PRK ) combined with accelerated epithelium‐off cross‐linking ( AXL ) for the treatment of progressive keratoconus ( CXL ‐Plus). Methods This study was a prospective multicentre comparative clinical study. A total of 125 eyes of 75 patients with grade 1 keratoconus and documented progression were divided into two groups. Group A included 58 eyes treated with standard CXL . Group B included 67 eyes treated with combined PRK and AXL . The recorded data included UDVA , CDVA , subjective and objective refraction, keratometry and pachymetry using corneal topographies preoperatively and postoperatively at 3, 6, 12 and 24 months of follow‐up. Results In group A, at 24 months of UDVA and CDVA were improved from 1.12 ± 0.38 and 0.58 ± 0.42 to 0.66 ± 0.20 and 0.20 ± 0.12 (Log MAR ± SD ). The spherical equivalent was reduced from 4.03 ± 1.18 to 1.78 ± 1.04 D. The cylinder reduction was 0.32 ± 0.19 D. In group B, at 24 months of UDVA and CDVA were improved from 1.26 ± 0.52 and 0.68 ± 0.36 to 0.58 ± 0.28 and 0.20 ± 0.16 (Log MAR ± SD ). The spherical equivalent was reduced from 4.23 ± 0.95 to 1.92 ± 0.74 D. The cylinder reduction was ±1.76 D. Conclusion Surprisingly, standard CXL showed close results to CXL ‐Plus at the 24th follow‐up month. Standard CXL acted as a stabilizing procedure associated with a late myopic component reduction. CXL ‐Plus acted as a refractive and stabilizing procedure with an early effect on both the myopic and the astigmatic component but no later improvements. Standard CXL seems to be more powerful than AXL in its long‐term effect. Therefore, in the future, we want to test the combination of PRK with standard CXL .

<p>Visual and Refractive Long-Term Outcomes Following Standard Cross-Linking in Progressive Keratoconus Management</p>

“…Furthermore, Iqbal et al28 compared SCXL versus CXL Plus (combined ACXL and photorefractive keratectomy). They finally concluded that SXCL had close outcomes to CXL Plus at 24-month follow-up.…”

Advances in the diagnosis and treatment of keratoconus

“…As such, it is more accepted and preferred all over the world as being a safer and more effective method in the long term. 93 , 94 …”

Combined Protocols for Corneal Collagen Cross-Linking with Photorefractive Surgery for Refractive Management of Keratoconus: Update on Techniques and Review of Literature

“…Kanellopoulos et al initially showed same-day topography-guided PRK with CXL as more effective for visual rehabilitation (as incorporated into the Athens protocol), with subsequent studies corroborating increased efficacy of simultaneous CXL and PRK compared with CXL alone [40–45]. However, a recent prospective multicenter study comparing conventional CXL (Dresden protocol) to simultaneous combined PRK and CXL (Athens protocol) showed nearly equivalent results in visual outcomes and refractive improvement after 2 years, suggesting that there may not be a significant benefit with the Athens protocol over the longer-term refractive advantages of the conventional protocol [46]. Primary considerations for planning simultaneous combined CXL and PRK concern ablation depth and corneal thickness, so most protocols specify a maximum ablation depth between 50 and 80 μm [34, 41, 42].…”

“…For combined CXL with PRK (Athens protocol), there is consistent level 4 evidence that shows its safety and efficacy. However, there is some controversy within level 3 studies that suggest the longer-term results may not be significantly improved compared with CXL alone [44, 46]. For this reason, we offer a grade C recommendation for this procedure.…”