EXTRACORPOREAL OPTIMIZATION OF CORNEAL ALLOGENIC INTRASTROMAL RING SEGMENTS (ECO-CAIRS): INITIAL CLINICAL EXPERIENCE
Published 2026 - 30th ESCRS Winter Meeting
Reference: PP01.02 | Type: Free Paper | DOI: 10.82333/x83a-2f82
Authors: Farhad Hafezi** 1 , M. Enes Aydemir 1 , Mark Hillen 1 , Shady T. Awwad 2 , Léonard Kollros 1 , Fabian Müller 3 , Cosimo Mazzotta 4 , Michalina Depczyńska 1 , Nikki Hafezi 1 , Larissa Paulasto 1 , Emilio A. Torres-Netto 1
1ELZA Institute,Zurich,Switzerland, 2American University of Beirut Medical Center,Beiruit,Lebanon, 3Ziemer Ophthalmic Systems,Port,Switzerland, 4University of Siena,Siena,Italy
Purpose
To describe a new modification of corneal allogenic intrastromal ring segment (CAIRS) surgery in which the donor corneal tissue is cross-linked extracorporeally using ultra-high-fluence ultraviolet (UV) corneal cross-linking (CXL) prior to implantation—termed Extracorporeal Corneal Cross-Linking of Allogenic Intrastromal Ring Segments (ECO-CAIRS).
Setting
ELZA Institute, Zurich, Switzerland.
Methods
ECO-CAIRS was performed in four eyes of four patients (ages 35–48 years) with stable keratoconus (Kmax 58.0–69.8 D). Donor corneas unsuitable for keratoplasty were used to prepare femtosecond laser-cut allogenic ring segments, which were cross-linked extracorporeally with 30 J/cm² or 60 J/cm² UV fluence before insertion. Segments were saturated in 0.1% riboflavin and irradiated at 365 nm using the C-eye device (EMAGine AG, Zug, Switzerland). Postoperative follow-up included slit-lamp examination and anterior-segment OCT imaging to monitor segment thickness and position.
Results
Insertion was uneventful in all cases. Ultra-high-fluence cross-linking rendered the ring segments stiff, maintaining rigidity throughout insertion and preventing intraoperative softening. Immediately after CXL, ring segment thickness decreased by approximately 50% (e.g., 650 µm to 252 µm) but re-increased within days after implantation (mean +110 µm by day 2). No complications were observed, and the yellow coloration of cross-linked tissue disappeared within one week.
Conclusion
ECO-CAIRS produces hardened, acellular collagen ring segments that remain mechanically stable during implantation. The technique offers improved handling, reduces the risk of keratocyte transmission, and may allow the insertion of larger tissue volumes for enhanced corneal flattening. Ultra-high-fluence extracorporeal CXL appears to provide a safe, effective optimization of allogenic ring segment surgery.