Extracorporeal Optimization of Corneal Allogenic Intrastromal Ring Segments (ECO-CAIRS) Using Ultra-high-Fluence...

Area of Science:

• Ophthalmology
• Corneal Surgery
• Biomaterials Science

Background:

• Keratoconus is a progressive thinning disorder of the cornea.
• Corneal allogenic ring segments (CAIRS) are used to correct keratoconus.
• Current CAIRS insertion can be challenging due to softening and swelling.

Purpose of the Study:

• To describe a novel surgical technique for treating keratoconus using femtosecond laser-created CAIRS.
• To evaluate the use of extracorporeal ultra-high-fluence corneal cross-linking (CXL) on CAIRS before stromal insertion (ECO-CAIRS).

Main Methods:

• Four eyes with stable keratoconus underwent implantation of femtosecond laser-prepared CAIRS.
• CAIRS were subjected to ultra-high-fluence CXL (30 and 60 J/cm² UV light).
• Segments were inserted without air-drying or extended dehydration.

Main Results:

• CAIRS insertion was uneventful in all cases.
• Ultra-high-fluence CXL-treated CAIRS maintained stiffness during insertion, resisting softening.
• Segment thickness temporarily decreased post-CXL, then increased after insertion.

Conclusions:

• ECO-CAIRS offers advantages over standard CAIRS, including easier insertion due to enhanced stiffness.
• High UV fluence likely renders CAIRS acellular, creating a stable collagen scaffold.
• The temporary thickness reduction may allow for larger volume segments, potentially enhancing topographical correction.