Ongoing stromal melt after corneal allogenic segment implantation in exchange for an explanted synthetic segment due to melt

Introduction: To report a case of ongoing stromal melt after the insertion of a corneal allogenic intrastromal ring segment (CAIRS) after explanting a synthetic intrastromal corneal ring segment (ICRS) due to stromal melt. Patient and Clinical Findings: A 72-year-old woman with bilateral keratoconus with 2 ICRS in the left eye inserted 20 years ago presented with tearing and discomfort in this eye. Optical coherence tomography (OCT) revealed stromal thinning anterior to the inferotemporal part of the segment with stromal hyporeflectivity over the inferonasal part. 2 months after conservative management, the lower ring was explanted and a 550 μm CAIRS was implanted in the same tunnel and location. Topography was mildly improved. Diagnosis, Intervention, and Outcomes: 4 months later, the patient presented with the same symptoms. Slitlamp examination and OCT revealed a linear defect in the inferonasal area overlying the CAIRS. 1 month after management with antibiotics and loteprednol, the CAIRS was removed. Visual acuity and topography worsened compared with preexplantations of the ICRS and CAIRS. Conclusions: Anterior stromal melt treated by ICRS exchange with CAIRS can occasionally lead to stromal melt in other locations overlying the tunnel. This may develop with altered nutrient diffusion attributed to prior ICRS implantation, underlying inflammation, and increased anterior stromal mechanical stress, especially with large CAIRS sizes.