Keratoconus treatment - accelerated CXL outcomes comparable to conventional CXL in study

Accelerated corneal crosslinking (A-CXL) appears to offer comparable levels of safety and efficacy to conventional crosslinking (C-CXL) for the treatment of progressive keratoconus, according to a study presented at the French Implant and Refractive Surgery Association (SAFIR) annual meeting in Paris. “Our study showed comparable clinical outcomes and tolerance up to 24 months postoperatively between the two crosslinking techniques. Naturally, there is a clear time-gain with A-CXL treatments which would allow more patients to be treated, but the statistical trend supported by biomechanical and structural observations is still in favour of C-CXL over the longer term,” said Antoine Robinet MD. Dr Robinet’s single-centre retrospective study included 837 eyes with progressive keratoconus indicated for CXL between January 2007 and January 2015 at Bordeaux University Hospital, France. A total of 254 eyes were included in the final analysis – 118 were treated with C-CXL from January 2007 to July 2011, and 136 with A-CXL from July 2011 to January 2015. The Dresden Protocol, considered by many to be the gold standard for CXL treatments, was used for C-CXL. After removal of the epithelium, a 0.1 per cent riboflavin (Ricrolin®, Sooft) in an isotonic Dextran solution (Pharmacosmos) was applied to the cornea for 30 minutes, followed by exposure of ultraviolet-A light for another 30 minutes at 3mW/cm2 for a total dose of 5.4 J/cm2. The total procedure time for C-CXL was 80 minutes. The A-CXL procedure was also epi-off, followed by 10 minutes of 0.1 per cent riboflavin (VibeX, Avedro Inc.) and Dextran for three minutes at 30 mW/cm2 for a total dose of 5.4 J/cm2. Total treatment time for A-CXL was 35 minutes, said Dr Robinet. Inclusion criteria included patients with confirmed progressive keratoconus, defined as a change in corneal curvature (Kmax) of more than 1.0D in six months.

CLINICAL EVALUATION

Clinical evaluation was carried out at six months, 12 months and then every six months subsequently up to 24 months. Examinations included uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), topography measurements and clinical tolerance of the treatment. Efficacy criteria was categorised according to Kmax with “progression” defined as a mean Kmax more than 1.0D, “stability” less than 1.0D and “regression” more than -1.0D. At 24 months, results were marginally better for C-CXL: the mean Kmax for C-CXL was -0.92D (±1.01), mean Kmin was -0.73D (±0.88) and mean cylinder was -0.19D (0.61). For A-CXL, the mean Kmax was -0.59D (±0.77), Kmin was -0.34D (±0.50) and -0.25D (±0.55). In terms of evolution profiles, C-CXL reported 70.5 per cent stable, 10.6 per cent progression and 18.9 per cent regression, while the figures for A-CXL were 71.3 per cent, 11 per cent and 17.7 per cent, respectively. Antoine Robinet: antoine.robinet-perrin@hotmail.fr