Diamond Burr for the Treatment of an Indolent Corneal Ulcer in a Foal
Authors: Pigatto João Antônio Tadeu , De Albuquerque Luciane , Bacchin Ângela Beatriz de Oliveira , Da Silva Géssica Maria Ribeiro , Petersen Michelle Becker , Reiter Gabriela Grandi 
Published: December 2021

Background: Indolent corneal ulcers have been described as superficial ulcers with an associated rim of loose peripheral epithelium Treatment for indolent ulcers include debridement, grid keratotomy, multiple punctate keratotomy, third eyelid flaps, application of cyanoacrylate tissue adhesives, superficial keratectomy, and a debridement with a diamond burr.Case: A 2-month-old female American Quarter Horse was referred to the Ophthalmology Veterinary Section of the Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil, presenting epiphora and blepharospasm. A local veterinarian doctor had prescribed broad spectrum topical antibiotic and anti-inflammatory drops, although there was no positive response to the treatment for the past two weeks. Ophthalmic examination reveals and moderate discomfort in the left eye, epiphora, and mild corneal edema in the area of the defect. Slit lamp biomicroscopy revealed a superficial corneal ulcer with about 6 mm. Corneal epithelium did not adhere to underlying corneal stroma. The remainder of the ophthalmic examination of the left eye was unremarkable. The diagnosis of a corneal ulcer was made based on these clinical signs and fluorescein staining of the cornea where the stain dissects under the unattached epithelial lip. A handheld battery-operated motorized diamond burr, with a 3.5 mm medium grit tip, was utilized to remove the epithelium. The medical treatment included tobramycin eye drops, and flurbiprofen sodium ophthalmic solution, being applied six times daily, after the procedure, during two weeks, and atropine sulphate 1% was applied once a day, during three days. The foal was hospitalized until healing the corneal ulcer. For two weeks, the foal was assessed daily, and, after that, follow-up visits were scheduled weekly for four months. Healing was defined as the point at which the cornea no longer retained fluorescein.Discussion: Ulcers localized to the corneal epithelium, do not heal within the expected time frame, and have been characterized by epithelial border poorly adherent corneal and being commonly referred as indolent corneal ulcers. In this case, corneal ulcers are chronic and have not responded to an appropriate therapy for 14 days. The corneal ulcer was diagnosed based on history, clinical signs and fluorescein staining of the cornea. Usually, medical treatments provide disappointing results. Surgical treatment aims to remove the loosened epithelium in order to facilitate the growth of new epithelial cells, with stronger adhesion complexes. The utilization of a diamond burr, for the treatment of an indolent corneal ulcer, has been previously reported in humans, and dogs. In the present case, the debridement with a diamond burr was chosen on account of excellent results obtained in previous studies in humans and dogs, when treating indolent corneal ulcers. In the current case, the corneal ulcer healed in ten days, while in a study comparing the outcome in 23 horses treated by debridement, grid keratotomy, or superficial keratectomy, the mean times until complete healing were 15, 16 and 23 days, respectively. In the present case, debridement with diamond burr was effective in the treatment of a recurrent corneal ulcer in a foal.