Riboflavin and Ultraviolet Light A Therapy as an Adjuvant Treatment for Medically Refractive Acanthamoeba Keratitis: Report of 3 Cases

Abstract

To present the first 3 cases of Acanthamoeba keratitis (AK), unresponsive to medical treatment, that were successfully treated with a novel adjunctive therapy using ultraviolet light A (UVA) and riboflavin (B2). Interventional case series. Two patients with confirmed AK and 1 patient with presumptive AK, which were all refractive to multidrug conventional therapy. Two treatment sessions involving topical application of 0.1% B2 solution to the ocular surface combined with 30 minutes of UVA irradiation focused on the corneal ulcer. Clinical examination by slit lamp, confocal microscopy, and histopathology, when available. All patients in these series showed a rapid reduction in their symptoms and decreased ulcer size after the first treatment session. The progress of the clinical improvement began to slow after 1 to 3 weeks of the first application and was then renewed after the second application. All ancillary signs of inflammation mostly resolved after the second treatment session. The ulcers in all patients continued to decrease and were closed within 3 to 7 weeks of the first application. Two patients developed dense central corneal scars, and penetrating keratoplasty was performed for visual rehabilitation. Histopathologic examination of the excised tissue revealed no Acanthamoeba organisms. The remaining patient had no symptoms or signs of infection, both clinically and by confocal microscopy, and was left with a semitransparent eccentric scar that did not affect visual acuity. The adjunctive use of UVA and B2 therapy seems to be a possible alternative for selected cases of medication-resistant AK.