A REVIEW OF CORNEAL ALLOGENIC INTRASTROMAL RING SEGMENTS

To review the current literature on Corneal Allogenic Intrastromal Ring Segment (CAIRS) focusing on the indications, evolving technique modification, visual and tomographic outcomes, and safety profile. CAIRS was first introduced in 2015 and represents another innovative option for managing corneal ectatic disorders, particularly keratoconus.

Sussex Eye Hospital, University Hospitals Sussex NHS Foundation Trust, Brighton.

A literature review was conducted in PubMed/Medline and Google Scholar to identify any studies regarding CAIRS in English. Inclusion Criteria were studies with more than 20 eyes and minimal follow-up of 6 months. This comprehensive literature review will provide a detailed description of the CAIRS procedure, including patient selection, safety profile, and the different modifications that enable tailored patient treatment. We will summarise and discuss the various studies' visual and topographic long-term outcomes and the combination of CXL.

The current studies demonstrate a significant improvement in topographic and visual acuity parameters, sometimes up to 4 lines. The results showed a mean decrease of 4.35 ±2.78 D in K-max and increased uncorrected and corrected visual acuity by 0.25 ±0.06 and 0.28 ±0.11 (Snellen decimal), respectively. Unlike synthetic corneal segments, CAIRS are derived from donor corneal tissue, offering enhanced biocompatibility and a substantially reduced risk of complications such as infection or extrusion.

Those findings emphasise CAIRS as an evolving novel technique that can be used as an alternative for synthetic corneal ring segments or even replace corneal transplant surgery in some cases, with potential benefits in restoring corneal stability and improving visual acuity with a high safety profile. Results will be updated if more relevant studies will be published prior to the meeting.