Purpose
The conventional corneal collagen crosslinking (CXL), according to the Dresden protocole, have proved is efficiency on the stabilization of progressive keratoconus. However, this procedure presents various complications, due to the epithelial removal that is essential for riboflavin penetration into the corneal stroma. In this context, we wanted to evaluate a new riboflavin penetration procedure, the iontophoresis, in order to perform a CXL preserving the epihtelium.
Methods
Our randomized prospective multicentric clinical trial aims at compare a CXL using a riboflavin application by iontophoresis (I-CXL) to a CXL using a conventional de-epithelialized riboflavin application (C-CXL). Forty patients, aged over 18 years, with a progressive keratoconus have been included between April and November 2013, in accordance with the Declaration of Helsinki. The I-CXL involved the administration of a new formulation of charged riboflavin (Ricrolin+®) into cornea by applying a constant current of 1mA for 5 min. After this application, the cornea was irradiated with UVA light at 10mW/cm2 for 9 minutes. The C-CXL was performed in accordance with the Dresden protocole. The investigation included: per-operatory ocular fluorophotometry measurment, pain evaluation, visual acuity, topographic keratometry, counting endothelial cells, Ocular Coherence Tomography (OCT) of cornea, corneal confocal microscopy and ocular complications.
Results
The ocular fluorophotometry showed a riboflavin corneal concentration 2.5 times lower after I-CXL (752.8 ± 274.5 ng/ml) than after C-CXL (1902 ± 539.4 ng/ml) (p<0.05). Post-operative pains were less severe in the I-CXL patients group. At 1 month and 3 months, keratometry were stable in both groups. The OCT showed inconstantly a less pronounced and a less deep demarcation line in the I-CXL treated patients group. No complications were observed in the two groups.
Conclusions
These preliminary results suggest a less riboflavin penetration in the stroma but a similar effect on keratoconus stabilization 3 months after after I-CXL compared to C-CXL. I-CXL seems to be a promising alternative methodology for riboflavin delivery in crosslinking treatment, preserving the epithelium. However, a longer follow up on a larger number of patients is necessary. We will be able to present our following results at the ARVO annual meeting.
Keywords: 574 keratoconus