Microbial Keratitis After Corneal Allograft Intrastromal Ring Segment Implantation

Purpose: To report a case of microbial keratitis after sterile, precut allograft implantation for the treatment of keratoconus. Methods: This is a case report of 49-year-old male patient with keratoconus and an uncorrected visual acuity of 20/300 underwent implantation of a sterile, precut, packaged Corneal Allograft Intrastromal Ring Segment (CAIRS) in his left eye. Results: Two weeks later, the patient presented with a 2-day history of mild pain and redness in the operated eye and no history of trauma. Uncorrected visual acuity was 20/60, and slit-lamp examination revealed diffuse conjunctival injection, inferior CAIRS in place, and a 1.5-mm temporal linear infiltrate over the inner superior aspect of the CAIRS with a 3.5*3.5-mm surrounding edema without extrusion, exposure, thinning, or corneal epithelial defects. The infiltrate was away from the incision. Per routine procedures, a precautionary culture of the albumin packaging of CAIRS revealed Cutibacterium acnes (formerly Propionibacterium acnes ) species, and the patient was started on fortified vancomycin drops and a subconjunctival injection. After tailored treatment, the conjunctival injection and infiltrate gradually improved, with complete resolution. Conclusions: This case illustrates the risk of microbial keratitis after an uneventful CAIRS for corneal ectasia. Culturing the transport/packaging medium and remaining segments is crucial for early identification of causative infectious organisms. The clinical course is benign compared with prior reports of microbial keratitis with the polymethylmethacrylate rings.