Corneal CXL: Epi-on Versus Pocket Technique
To compare the efficacy and safety of Epi-on corneal crosslinking with crosslinking using a corneal pocket.
Patients with progressive Keratoconus or Pellucid Marginal Degeneration were randomized to either technique and followed for a minimum of 18 months. The study was unmasked. A total of 24 patients were randomized - 14 to Epi on and 10 to pocket crosslinking. Sequential topographies and wavefronts were taken pre-operatively and post-operatively q 3 monthly. Anterior and posterior topographies were obtained and a pachymetry map taken. Accelerated crosslinking was conducted and corneal pockets were created at 110 micron depth with a femtosecond corneal laser. Any surgical and post-operative complications were recorded.
All patients with Epi on treatments improved topographically and refractively within 24 hours. The Pocket patients only improved after a minimum of 6 weeks. All refractive and topographic gains regressed in the Epi on group by the 18 months mark. The pocket group improved up to the 12 months mark and remained stable at 18 months. Mean topography improved from 53.4+/-2.1 D in the Epi on group to 51.5+/- 1.9 vs. 52.9+/-1.85 D in the pocket group to 51.8+/- 2.2 at 3 months NS. At 18 months the mean topography had regressed to 53.6+/-2.5 in the Epi on group vs. 50.8 +/-2 in the pocket group P 0.03. There were no complications in either group.
Epi on corneal crosslinking appears to have a faster recovery but a limited longterm effect in the treatment protocol used. Pocket crosslinking appeared to be more effective in the medium term.