Clinical Outcomes Of Corneal Allogenic Intrastromal Ring Segments (Cairs) In Patients With Keratoconus

To evaluate visual, refractive, and tomographic outcomes following implantation of Corneal Allogenic Intrastromal Ring Segments (CAIRS) in patients with keratoconus.

Department of Ophthalmology Hull Royal Infirmary, United Kingdom.

This retroprospective interventional case series included 9 eyes of 9 patients with progressive keratoconus. All eyes underwent femtosecond laser-assisted stromal channel creation followed by implantation of CAIRS. Preoperative and postoperative assessments included corrected distance visual acuity (CDVA), corneal topography (Kmax, astigmatism), and anterior segment OCT. Primary outcomes were changes in Kmax and CDVA.

Nine patients were included. CDVA improved in 3/9 patients (mean gain 0.137 logMAR), worsened in 3/9 (mean loss 0.242 logMAR), and remained unchanged in 1/9. Postoperative CDVA was unavailable in 2/9 due to recent surgery. Subjectively, 3 patients reported visual improvement and 1 reported no change. Kmax decreased in 5/9 patients (mean reduction 4.45D) and increased in 2/9 (mean increase 22.02D). Astigmatism decreased in 5/9 (mean reduction 2.7D) and increased in 2/9 (mean increase 3.6D), demonstrating variable visual and topographic outcomes.

In this small cohort, the procedure demonstrated variable visual and topographic outcomes. While a proportion of patients experienced improvement in CDVA, Kmax, and astigmatism, others showed deterioration in these parameters. Overall, the findings suggest potential corneal flattening and astigmatic reduction in selected cases; however, the variability observed highlights the need for careful patient selection and close postoperative monitoring. Larger studies with longer follow-up are required to better define efficacy, stability, and safety outcomes.