Corneal Enzymatic Resistance To Digestion Following Corneal Cross-Linking Combining Riboflavin/Uv-A Light And Rose Bengal/Green Light

Published 2023 - 41st Congress of the ESCRS

Reference: FP02.05 | Type: Free paper | DOI: 10.82333/4q1z-gt13

Authors: M. Enes Aydemir* ¹ , Nikki L. Hafezi ¹ , Emilio A. Torres-Netto ¹ , Nanji Lu ¹ , Mark Hillen ¹ , Farhad Hafezi ²

¹Ophthalmology,ELZA Institute AG,Dietikon,Switzerland, ²Ophthalmology,ELZA Institute AG,Dietikon,Switzerland;Ocular Cell Biology Laboratory,University of Zurich,Zurich,Switzerland

Purpose

Photoactivated chromophore for keratitis corneal cross-linking (PACK-CXL) is an emerging treatment modality for infectious keratitis. In PACK-CXL, both riboflavin(RI)/UV-A and rose bengal (RB)/green light chromophore/light combinations are used to treat infectious keratitis. Each combination results in different penetration depths and clinical outcomes, and both approaches increase corneal enzymatic resistance to digestion. The absorption spectra of both chromophores barely overlap, so we investigated if PACK-CXL with RI/UV-A and RB/green light performed sequentially in the same setting further increases the cornea’s resistance to digestion, when compared to PACK-CXL using a single chromophore.

Setting

Laboratory study. ELZA Institute, Dietikon, Switzerland and Laboratory for Ocular Cell Biology, CABMM, University of Zurich.

Methods

Porcine corneas (n=58) were assigned to 3 groups. Group 1 received PACK-CXL with RI/UV-A using a fluence of 10 J/cm² and group 2 received PACK-CXL with RB/green light using a fluence of 10 J/cm². Experimental Group 3 received PACK-CXL with RI/UV-A using 10 J/cm², immediately followed by RB/green light irradiation using 10 J/cm² in the same setting. All corneas were digested in 0.3% collagenase A solution. Time until complete dissolution was assessed.

Results

The mean times to digestion in Groups 1 to 3 were: 30.61 ± 1.79 h, 33.7 ± 2.38 h and 39.82 ± 2.16 h, respectively.

Combining PACK-CXL with RI/UV-A and RB/green light in the same setting showed a greater resistance to digestion than RI/UV-A or RB/green light alone (both P < 0.001); While Group 2 achieved a significantly increased resistance compared to Group 1 (P = 0.048).

Conclusions

Combining RI/UV-A and RB/green light photoactivation in the same setting significantly increases corneal resistance to enzymatic digestion and is superior to photoactivation using a single chromophore/light combination. We recently showed that the combination of both chromophore/wavelengths was able to successfully treat a patient suffering from therapy-resistant acanthamoeba keratitis. Combining RI/UV-A and RB/green light PACK-CXL in the same setting might represent a novel PACK-CXL approach.