Objective: This study aims to compare the long-term outcomes of standard corneal collagen crosslinking with accelerated corneal collagen crosslinking (CXL) for progressive keratoconus.
Patients and methods: This prospective, comparative study included 79 eyes with progressive keratoconus, which were randomly assigned: 42 eyes received a standard CXL procedure, and 37 eyes were treated with the accelerated CXL protocol. We evaluated the following parameters, before the procedure and 1 month, 6 months, 12 months and 24 months postoperatively: best corrected visual acuity (BCVA), manifest refraction spherical equivalent (MRSE), cylindrical values, corneal dioptric powers on the steepest meridian (Kmax), central corneal thickness (CCT); demarcation line depth (DLD) preoperatively and 1 month after the CXL procedure.
Results: The BCVA, MRSE, cylindrical values, Kmax, CCT improved significantly, after both the accelerated and the standard CXL procedure. Throughout the 24-months follow-up, BCVA improvement was achieved sooner in the accelerated group (after 1 month, vs. after 3 months). However, there were no statistically significant differences between the two groups in these aspects. The DLD-to-CCT was significantly greater in the standard group (66% vs. 62%, p = 0.02).
Conclusions: Standard and accelerated CXL are effective in stabilizing keratoconus progression in the long term. In clinical practice, the accelerated protocol has the added benefit of a faster visual recovery, in addition to the known reduced treatment time and increased comfort.