Safety and efficacy of collagen cross linking for donor corneal button in therapeutic penetrating keratoplasty

Purpose: To study the role of collagen crosslinking (CXL) of donor corneal tissue in preventing recurrence of infection after therapeutic penetrating keratoplasty (TPK). Materials and Methods: This was a prospective, clinical, interventional case study done from May 2016 to July 2017. 15 cases and 15 controls were enrolled in the study. Patients who had infectious keratitis and needed TPK were included in the study. Pediatric patients, one eyed patients, perforated ulcers, patients with limbal/scleral involvement or posterior segment involvement or any other significant co-morbidity were excluded. In patients who were enrolled as cases, donor cornea was subjected to CXL using modified Dresden protocol just before TPK. TPK was done as per standard protocol. 3 cases and 2 controls had lens removal and required vitrectomy. All cases and controls were assessed post operatively on day 1, day 7 and 1 month post operatively. Digital slit lamp photos were taken at each visit for documentation of recurrence of infection, if any. The patients were followed up for at least 3 months duration. Results: Etiology was fungal in 13 cases and 2 cases were culture and smear negative. Among controls, etiology was fungal in 10, mixed bacterial and fungal in 1, acanthamoeba in 2, microsporidial in 1 and 1 was culture and smear negative. Recurrence of infection was found in 2 cases and in 4 controls within 1 month of TPK (Odd's ratio 2.36). Conclusion: CXL done on donor corneal tissue before transplantation has got a positive role in reducing recurrence of infection after TPK.