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  • Cornea/External Disease

    Decreasing the standard riboflavin induction times by half during corneal crosslinking treatment for keratoconus appears to have no significant impact on the success of the procedure, according to this multinational study.

    Study design

    This was a retrospective study of 280 eyes from 237 patients from the Save Sight Keratoconus Registry (SSKR). Included patients were diagnosed with keratoconus and underwent epithelium-off corneal cross-linking using a standard ultraviolet A protocol (3 mW/cm2 for 30 minutes) and either a standard (30 minutes) or shortened (15 minutes) riboflavin induction period prior to ultraviolet treatment. Measured outcomes for comparison between the standard and short riboflavin induction groups included BCVA, tomography measures, and secondary events from surgery.


    One-year follow-up showed no significant differences between the standard and short riboflavin induction groups in terms of changes to BCVA, flattening of keratometry in the steepest meridian, or mean corneal thickness. The short riboflavin induction group showed overall greater maximum keratometry flattening and a higher percentage of patients with a small increase in corneal thickness, but it also reported a greater rate of haze.


    This is a retrospective study using data from multiple clinical centers. Therefore, variability is seen in the type of riboflavin, the adjunct therapies used during cross-linking, and the type of tomographer, as well as in the country in which surgery was performed. Patients in the short induction group were from both countries (Italy and Australia) that contribute data to the SSKR, whereas almost all patients in the standard group were from Australia, which may have skewed the results. Another limitation is that a vast majority of included patients were Caucasian, limiting generalizability to other races.

    Clinical significance

    This study suggests that a shortened riboflavin induction time followed by standard UV treatment for corneal crosslinking yields comparable results to a standard induction time. If studies with longer follow-up times show similar results, shortening induction time could address one of the main limitations of the crosslinking procedure: its length of time. With a shorter procedure, more patients with keratoconus could potentially receive corneal crosslinking treatment and avoid long-term complications of this disease.

    Financial Disclosures: Dr. Afshan Nanji discloses a financial relationship with Beyeonics Surgical (Consultant/Advisor).