Long-term outcomes of riboflavin photodynamic antimicrobial therapy as a treatment for infectious keratitis

Abstract

Purpose: To report the long-term outcomes of three patients with infectious keratitis treated with riboflavin photodynamic antimicrobial therapy (PDAT). Observations: Case series reporting three patients with infectious keratitis unresponsive to standard medical treatment who underwent riboflavin photodynamic antimicrobial therapy (PDAT) as an adjunct therapy. One male and two female patients were treated, the median age of presentation was 58 years (range, 29–79 years). The organisms isolated and treated were Pseudomonas aeruginosa, Mycobacterium chenolae, and Curvularia spp. Different risk factors to develop corneal infection ulcers were identified, including corneal abrasion in a contact lens user, history of penetrating keratoplasty with chronic use of topical corticosteroids, and organic trauma. The median follow-up was 47 months (range 37–54 months), and there were no complications secondary to riboflavin PDAT treatment. Two cases underwent optical penetrating keratoplasty after infection was resolved and ocular surface was quiet for at least 3 years. Conclusions and importance: Riboflavin PDAT can be used as an adjunct treatment in infectious keratitis to strengthen the corneal collagen fibers, delay keratolysis, and allow more time for antimicrobials to work and this way prevent a corneal perforation. Keywords: Corneal infectious keratitis, Photodynamic antimicrobial therapy, Crosslinking, Riboflavin