Intraoperative Pachymetric Measurements during Corneal Collagen Cross-Linking with Riboflavin and Ultraviolet A Irradiation

ObjectiveTo study central corneal pachymetric variations during corneal collagen cross-linking (CXL) treatment with the use of riboflavin and ultraviolet A irradiation (UVA).DesignProspective, noncomparative, interventional clinical study.ParticipantsFifteen keratoconic patients (19 eyes) were enrolled.MethodsAll patients underwent riboflavin-UVA–induced corneal CXL. Intraoperative central corneal thickness (CCT) measurements using ultrasound pachymetry were performed during the procedure. Measurements were obtained after epithelial removal, after riboflavin drop instillation, and every 5 minutes (6 interval times) during UVA irradiation (30 minutes).Main Outcome MeasuresCentral corneal thickness measurements.ResultsMean patient age was 26.9±6.5 years (range, 17–40 years). Ten were male and 5 were female. Mean preoperative CCT was 458.5±21.5 μm (range, 427–494 μm; 95% confidence interval [CI], 448–467 μm) and 415.7±20.6 μm (range, 400–468 μm; 95% CI, 406–426 μm) before and after epithelial removal, respectively. There was a statistically significant decrease (mean, 75 μm) of CCT between the epithelial removal interval (415.7±20.6 μm; range, 400–468 μm) and at the end of riboflavin solution instillation (340.7±22.9 μm; range, 292–386 μm; P<0.001). There was no statistically significant change in CCT during irradiation (P>0.05). There was no statistically significant difference between preoperative and 1-month postoperative endothelial cell count (preoperative, 2780±197 to 1-month postoperative, 2713±116; P = 0.14). No intraoperative, early postoperative, or late postoperative complications were observed in this patient series.ConclusionsDuring corneal CXL with the use of riboflavin and UVA irradiation, a statistically significant decrease of CCT was demonstrated.Financial Disclosure(s)The author(s) have no proprietary or commercial interest in any materials discussed in this article.