Clinical Outcomes of Rose Bengal Photodynamic Therapy for Severe Infectious Keratitis

PURPOSE: To report the clinical outcomes, microbiological profile, and efficacy of Rose Bengal photodynamic therapy (RB-PDT) as adjuvant treatment in patients with severe infectious keratitis (IK). METHODS: Prospective, noncontrolled, interventional study. Severe IK was defined as meeting ≥2 of the following: central ulcer, infiltrate ≥3 mm, presence of corneal melting or hypopyon, and lack of clinical improvement with conventional medical treatment. Clinical success was defined as avoiding a therapeutic keratoplasty (TPK). RESULTS: A total of 21 eyes from 21 patients underwent RB-PDT. Clinical success was achieved in 61.9%. The mean follow-up was 9 ± 3.33 months (range: 4-15). Cultured samples were positive for 27 total microorganisms, including Fusarium spp (n = 12, 44.44%), S. epidermidis (n = 4, 14.81%), Acanthamoeba (n = 2, 7.40%), Pseudomonas spp (n = 3, 11.11%), and others. Cultured samples were grouped into bacterial (44.44%), fungal (48.14%), and polymicrobial (if cultured for multiple microorganisms, 28.57%) categories for analysis. Corneal melting (57.14%), hypopyon (57.14%), and fung-ball (38.1%) were present at the initial visit. The mean time from onset to clinical success was 89.69 ± 56.59 days. In cases of clinical success, the mean time from RB-PDT to clinical success was 46.69 ± 19.47 days. There was a total of 16 additional interventions, including evisceration (2), optical penetrating keratoplasty (5), conjunctival flap (3), amniotic membrane transplant (1), and topical losartan therapy (5). Clinical variables associated with clinical failure included diabetes and fung-ball at presentation. CONCLUSIONS: RB-PDT shows potential as an adjuvant therapy for managing severe infectious keratitis. TPK was avoided in 61.9% of cases.