Fluorophotometry study of riboflavin in iontophoresis procedure and conventional cross linking

Purpose A longitudinal observational multicentric study is conducted in Ophthalmology departments of Gabriel Montpied Hospital in Clermont‐Ferrand and Purpan Hospital in Toulouse. The aim of our study is to evaluate and compare the variations of riboflavin concentration in vivo through fluorophotometry in the anterior segment, during iontophoresis procedure (I‐CXL) and conventional cross‐linking (C‐CXL) for keratoconus patients. Methods Inclusion criteria are patients from 18 to 40 years old, with progressive keratoconus and a corneal pachymetry higher than 400μm at the thinnest point. Exclusion criteria are patients with central corneal opacities or patients with previous history of corneal disease or corneal surgery. The use of Fluorotron Master FM‐2® for anterior segment fluorophotometry allows us to study the concentration of fluorescent molecules in the cornea and in the anterior chamber, with an automated processing. Results Corneal concentration of riboflavin increases during instillation until a plateau is reached for both procedures. Though, the measurements for I‐CXL show a lower corneal concentration of riboflavin, about 50% less than the concentration in C‐CXL. More results are to come and will be presented during the EVER meeting. Conclusion This is the first in vivo study of riboflavin corneal concentration kinetics in keratoconus patients. This fluorophotometry study needs to be complemented by the results of current clinical studies.