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High fluence iontoforetic collagen cross-linking: in vivo OCT imaging of riboflavin penetration

Session Details

Session Title: Cross-linking

Session Date/Time: Monday 07/10/2013 | 14:30-16:30

Paper Time: 15:20

Venue: Elicium 2 (First Floor)

First Author: : M.Rechichi ITALY

Co Author(s): :    R. Vinciguerra   V. Scorcia   E. Legrottaglie   P. Rosetta   P. Vinciguerra  

Abstract Details

Purpose:

To evaluate in vivo riboflavin penetration during collagen cross-linking (CXL) performed with iontophoresis versus conventional epithelium-off protocol (epi-off) using high resolution optical coherence tomography( HD OCT).

Setting:

Eye Center, Humanitas Clinical and Research Center, Rozzano (MI), Italy. Magna Graecia University, Catanzaro, Italy.

Methods:

In this prospective, observational, comparative case series, patients with progressive keratoconus undergoing CXL with riboflavin and ultraviolet A (UVA) light were enrolled. 20 eyes (20 patients) undergoing CXL using were acquired pre, intra and postoperatively using HD OCT. In 10 eyes, the epithelium was removed completely in the central 9-mm zone (epi-off group) whereas in the remaining 10 eyes riboflavin penetration through intact epithelium was promoted by iontophoresis device (iontophoresis group). The iontophoresis device for corneal application (8mm in diameter) is placed on the cornea using an annular suction ring (low suction created by a syringe connected on the suction annulus). The device is filled with approximately 0.5 ml solution from the open proximal side, until the electrode (stainless steel mesh) is covered. The device is connected to a constant current generator (I-ON CXL, Sooft, Italy) set at 1mA (the total dose of 5 mA x min is monitored by the generator). The depth of hyperreflective band (representing penetration of riboflavin) in the anterior corneal stroma was measured.

Results:

In the conventional epi-off group, after 30 minutes of passive impregnation, an homogeneous hyperreflective band without fading effect was measured at mean depth of 80 ?m. In the iontophoresis group, we observed a less homogeneous hyperreflective band with a fading effect extending through the anterior 200 ?m of the cornea. This band was not visible until the end of irradiation time.

Conclusions:

Intraoperative OCT imaging could be an useful technique to evaluate in vivo penetration of riboflavin inside the cornea. Although we can"t still demonstrate the correlation between the band"s intensity and riboflavin stromal concentration, we speculate that an higher OCT reflectivity should be positively correlated with it. These results confirm early preclinical evidences which showed that iontophoresis allows penetration of riboflavin through an intact epithelium. The in-vivo OCT results of iontophoresis group , according to our hypothesis, showed a lower concentration of riboflavin in the stroma compared to epi-off technique. More studies are needed to evaluate if this difference could correlate with clinical CXL results.

Financial Interest:

... receives consulting fees, retainer, or contract payments from a company producing, developing or supplying the product or procedure presented