[Clinical analysis of corneal interface infection]

Objective: To analyze the clinical features of corneal interface infection. Methods: A retrospective case series study was conducted to explore the clinical features of interstitial corneal infection. The data of eight patients (eight eyes) who were diagnosed with interstitial corneal infection after undergoing corneal transplant or corneal refractive surgery and visited Beijing Tongren Eye Center from January to December 2018 were collected, including two male and six female patients aged between 18 and 55 years (median age, 27 years). The patients' general information, surgical type, onset time, and clinical manifestations were recorded. The lesions were examined by in vivo corneal laser confocal microscopy (IVCM), and microbial cultures and drug sensitivity tests were performed. Results: Among the 8 patients, 4 had undergone small-incision lenticule extraction (SMILE), 2 had undergone lamellar keratoplasty, and 2 had undergone endothelial keratoplasty. The onset of infection occurred between 2 and 30 days after surgery, with a mean of 9.8 days. Among the 3 patients who had undergone SMILE, the treatment outcome was corneal haze or opacity, while the remaining 5 cases required corneal transplantation for interstitial infections. The pathogens of the 4 cases of interstitial infection after corneal transplantation were all Candida species. Under the IVCM, patients with corneal interstitial bacterial infections showed a large amount of necrotic tissue with no normal tissue structure in the corneal stroma, with infiltration of inflammatory cells and local aggregation of inflammatory cells, but no typical pathogen was observed. Patients with fungal infections showed fungal hyphae under the corneal cap (filamentous fungal infection) or dense, punctate, high-reflection structures in the corneal interstitial space (yeast-like fungal infection). Conclusions: Corneal interlayer infection is difficult to diagnose early and has a poor prognosis. IVCM can assist in early diagnosis. The pathogen spectrum of corneal interlayer infection may differ from that of corneal infection caused by trauma.