Complications After Corneal Allografts Intrastromal Rings Segments (CAIRS) In Keratoconus And Post LASIK Ectasia A Case Series

Purpose: To report a multicenter case series describing complications following Corneal Allogenic Intracorneal Ring Segments (CAIRS) implantation in keratoconus patients and in post LASIK ectasia case, focusing on corneal neovascularization (CNV), lipoid keratopathy, and segment extrusion, and to analyze associated risk factors, clinical course, and management strategies. Methods: This retrospective case series includes 9 patients (9 eyes) from three countries, treated by three experienced corneal surgeons, who developed complications following CAIRS implantation, either alone or combined with corneal collagen crosslinking (CXL). Clinical presentation, imaging findings, management approaches, and postoperative outcomes were reviewed. Results: Complications observed included progressive CNV invading the CAIRS tunnel, lipoid keratopathy secondary to chronic vascular leakage, stromal inflammation and segment extrusion. Contributing factors included excessive preoperative corneal thinning, superficial tunnel creation, and postoperative delays in monitoring or treatment. Management required medical therapy such as topical corticosteroids, as well as surgical interventions including CAIRS explantation or trimming. Conclusions: Although CAIRS generally provide effective visual rehabilitation in keratoconus and are considered more biocompatible than synthetic intrastromal rings, complications are reported on only three cases in the literature. We report on post CAIRS complications including CNV, stromal lipid deposition, and extrusion in nine cases. Early detection, aggressive management of inflammation and neovascularization, careful patient selection, and precise surgical technique are essential to reduce risk. This multicenter series, the most numerous reported in the literature highlights the need for standardized guidelines for CAIRS implantation and postoperative surveillance.