Equine ulcerative keratitis with furrow: A review of the outcomes of 72 cases from 1987 to 2015

Abstract

Summary Background Ulcerative keratitis with peripheral furrow formation is a poorly‐described condition which has been associated with a grave prognosis due to rapid necrosis of the cornea. Objective To describe the infectious aetiologies associated with furrow‐forming ulcerative keratitis, its overall clinical course and the efficacy of medical and surgical intervention in horses. Study design Retrospective clinical case series. Methods Medical records of 72 horses which presented with furrow‐forming ulcerative keratitis at the University of Florida between 1987 and 2015 were reviewed. Results Seventy‐two horses (72 eyes) with furrow‐forming ulcerative keratitis were treated at the University of Florida between 1987 and 2015. Of these, a definitive aetiologic diagnosis was available for 37 eyes. Ten of 37 eyes (27%) were diagnosed with fungal keratitis based on cytology of corneal scraping, culture, histopathology and/or fungal PCR. Fourteen of 37 eyes (38%) were diagnosed with a mixed fungal and bacterial keratitis. Thirteen of 37 eyes (35%) were diagnosed with bacterial keratitis. Overall, 26 of 72 total eyes were treated with medical therapy alone (36%). Forty‐six of 72 eyes were treated medically and surgically (64%). Of the 26 eyes which received medical therapy, 20 healed with a positive visual outcome (77%) and 6 eyes were non‐visual (23%). Of the 46 eyes which received surgical intervention, 40 healed with a positive visual outcome (87%), while six eyes were non‐visual (13%). Altogether, 60 of 72 eyes healed with a positive visual outcome following medical or surgical treatment of furrow‐forming ulcerative keratitis (83%). Twelve of 72 eyes failed treatment (17%), with six eyes requiring enucleation and six globes becoming phthisical after treatment. Main limitations Inconsistencies in available medical record data due to the large span of time (1987–2015) are inherent in this retrospective study, along with gradual evolution of corneal surgical techniques and medical therapies over the decades. Conclusions Furrow‐forming ulcerative keratitis was associated with a positive visual outcome in 83% of horses treated at the University of Florida between the years 1987 and 2015. Furrow formation may be associated with either fungal or bacterial infection.

Highlights of recent clinically relevant papers

“…In this retrospective case series, William Berkowski and colleagues in the USA aimed to describe the features and outcomes of horses with ulcerative keratitis with an associated peripheral furrow (circumferential thinning of the corneal stroma ≥ 20% deeper than the central lesion and surrounding cornea) .…”

Clinical insights: Ophthalmology in the eye of the beholder: Are we properly caring for horses with ocular disease?

“…A small case series by Sansom et al 6 reviewing six fungal keratitis cases in the UK found that a peripheral furrow or trough surrounding a fungal ulcer was associated with a worse prognosis compared to those without such a feature. A recent study from Florida 7 looked at the prognosis of corneal ulcer cases demonstrating a peripheral furrow (defined in their study as a circumferential thinning of corneal stroma which was ≥20% deeper than the central lesion and surrounding cornea), and found that only 65% of these cases had fungal involvement, with 35% demonstrating only bacterial infection (determined via cytological or histological examination, positive growth on culture media, the presence of fungal DNA on a PCR test, a clinical response to topical antimicrobial therapy, or a combination thereof). A peripheral furrow is evidence of severe corneal inflammation with stromal necrosis, and although overall several cases had a poor outcome (n = 12) the overall prognosis was favourable (83%) for globe survival and some vision (menace response positive).…”