Recurrence of Infection in Corneal Grafts After Therapeutic Penetrating Keratoplasty for Microbial Keratitis.

PURPOSE To determine the factors responsible for the recurrence of infection after therapeutic penetrating keratoplasty (TPK) in severe microbial keratitis. METHODS This is a retrospective interventional case series that reviewed the medical records of 229 consecutive patients (2005-2017) who underwent TPK for microbial keratitis at a tertiary eye care center in Central India. The primary outcome was recurrence of the primary infection. The factors responsible for recurrence were identified by univariate and multivariate regression analysis. RESULTS The overall outcomes were clear graft in 50 (21.8%) eyes, failed graft in 139 (60.7%) eyes, evisceration in 19 (8.3%) eyes, phthisis bulbi in 14 (6.1%) eyes, repeat TPK in 2 (0.9%) eyes, and anterior staphyloma in 1 (0.4%) eye. Recurrence occurred in 63 (27.5%) eyes within 16.2 ± 13.8 (range: 2-66) days. Univariate analysis identified fungal etiology (P = 0.001), ulcer size > 60 mm (P = 0.001), limbal involvement (P = 0.001), endothelial exudates (P = 0.024), retro-iris exudates (P = 0.001), corneal perforation (P = 0.005), coexisting endophthalmitis (P < 0.001), and graft size ≥ 10 mm (P < 0.001) as significant risk factors. Multiple logistic regression identified fungal etiology (P = 0.013), retro-iris exudates (P = 0.011), coexisting endophthalmitis (P = 0.004), and graft size ≥ 10 mm (P = 0.058) as independent risk factors for recurrence. Presenting visual acuity of 20/200 or better was seen in 49 (21.4%) and 39 (17%) eyes, and no light perception in 11 (4.8%) and 26 (11.4%) eyes at postoperative months 1 and 3, respectively. CONCLUSIONS Fungal etiology, retro-iris exudates, coexisting endophthalmitis, and larger grafts were susceptible to recurrence. Early surgery may mitigate most of these factors. Despite the risk of recurrence, TPK remains an effective treatment in severe nonresponsive keratitis.