Corneal allogenic intrastromal ring segments spontaneous rejection after uneventful surgery: case series detailing rejections, complications, and treatment

Introduction: This case report describes the first instances of spontaneous rejection of corneal allogenic intrastromal ring segments (CAIRS). The findings add to the scientific literature by highlighting a previously unreported complication associated with CAIRS, which has generally been considered a safer alternative to poly(methyl methacrylate) (PMMA) intrastromal corneal ring segments (ICRS). Patient and Clinical Findings: Patient A had progressive asymmetric keratoconus, underwent CAIRS implantation in the left eye. Postoperative complications included a small epithelial defect on day 1 and spontaneous CAIRS expulsion on day 4. Patient B, with severe keratoconus, presented with 2 minor epithelial defects on day 1 and also experienced partial spontaneous CAIRS expulsion. Diagnosis, Intervention, and Outcomes: Both patients had surgical management of their expulsion, with subsequent antibiotic and anti-inflammatory treatment. Despite the interventions, patient A presented with a persistent epithelial defect and patient B had an episode of infectious keratitis. After the resolution of these complications, patient A opted for medical treatment and patient B for surgical treatment. Conclusions: This report highlights the possibility potential for spontaneous CAIRS rejection. Although CAIRS offers a promising alternative to PMMA ICRS, careful monitoring and prompt management of postoperative complications are crucial to optimize patient outcomes.