Efficacy of riboflavin/UV-A corneal phototherapy as stand-alone treatment for ulcerative keratitis in horses

The purpose of this study was to assess the efficacy of riboflavin/UV-A corneal phototherapy in comparison with topical antimicrobials for the treatment of corneal ulcers in horses. Nineteen horses with a diagnosis of corneal ulceration were randomised to receive either corneal phototherapy (11 horses) or topical antimicrobial therapy (8 horses). The corneal phototherapy consisted in the application of a riboflavin-enriched ophthalmic solution onto the cornea for 20 min followed by cornea UV-A irradiation at 30 mW/cm2 for 3 min using a point-of-care UV-A device. A complete ophthalmological examination was performed at enrolment and then at day 1, 3, 7, 14, 21, 28, 35, 42, and 49 after treatment. The corneal ulcer was considered healed when the fluorescein staining was negative. The corneal phototherapy succeeded in the complete corneal wound healing in 91% cases (10/11 horses) by 12.7 ± 5.5 days. In the topical antimicrobial group, no horse showed improvement of the corneal ulceration (0/8; 0%) and two eyes had a corneal perforation. Six horses, due to an enlarged corneal lesion, underwent corneal phototherapy at day 14 and achieved complete wound healing by 17.2 ± 5.5 days in 83% cases (5/6). The corneal phototherapy was shown to be an effective and safe treatment for equine corneal ulcers.