Corneal Crosslinking May Not Require Repeated Riboflavin Application

Repeatedly applying riboflavin during the UV-A irradiation portion of the corneal crosslinking (CXL) procedure will likely not improve corneal stiffness, according to research published in Experimental Eye Research. 

Researchers conducted an ex vivo analysis of 66 porcine corneas and assigned them to 1 of 3 groups. All corneas were presoaked in a 0.1% isomolar riboflavin solution in a phosphate buffered saline solution. Group 1 and group 2 corneas underwent irradiation with a standard CXL UV-A protocol (3 mW/cm² for 30 minutes) while group 3 corneas served as controls. During UV-A irradiation, Group 1 corneas received repeated riboflavin solution application and group 2 participants received repeated phosphate buffered saline solution. The team evaluated elastic modulus following the procedure.

Mean elastic modulus, as a function between 5% and 10% of strain, was 4.22 N/mm, 4.33 N/mm, and 3.39N/mm in groups 1, 2, and 3, respectively. This indicates a significant difference in corneal biomechanical strength between corneas in groups 1 and 2 treated with UV-A irradiation and those not treated with UV-A irradiation (P =.005 and P =.002, respectively). However, no statistical significance was noted between corneas from groups 1 and 2 (P =.715), indicating that the solution used during irradiation did not increase elastic modulus. 

“In conclusion, the biomechanical strengthening effect of CXL was not significantly increased whether [phosphate buffered saline]-only or [phosphate buffered saline]-riboflavin were used during a CXL procedure ex vivo,” according to the researchers. “Consequently, it is not necessary to apply riboflavin during UV-A irradiation in a CXL procedure: riboflavin application can be discontinued at the end of the riboflavin soaking period.”

Study limitations include the use of ex-vivo testing and non-commercially available riboflavin solutions. 

Disclosure: Multiple study authors declared affiliations with biotech, pharmaceutical, and/or clinical research organizations. Please see the original reference for a full list of authors’ disclosures.