Patient demographics, and outcome of striate keratotomy versus diamond burr debridement for treatment of spontaneous chronic corneal epithelial defects in dogs in South Africa

Abstract

Background: Spontaneous chronic corneal epithelial defects (SCCED) are a common finding in canine patients referred for non-healing corneal ulceration. Various names have been used for this condition historically. The classic lesion and history include an axial or paraxial, superficial, corneal epithelial ulcer, that is non-responsive to topical therapy and is recurrent in nature. The lesions are not infected and not associated with any physical cause preventing healing. Pathology is well described, and various topical and surgical treatments have been used to treat SCCED lesions. Patient demographics for referral cases treated at a specialist veterinary ophthalmology hospital in South Africa, and the surgical outcome between striate keratotomy (SK) and diamond burr debridement (DBD) are reported in this study. Methods: Clinical records for dogs that presented with SCCED lesions over a five-year period between 1st January 2019 and 31 December 2023 were retrospectively evaluated. The patients were included if they were positively diagnosed with a SCCED lesion and underwent either a SK or DBD surgery. Year of surgery, patient demographics, intra-ocular pressure (IOP), Schirmers tear test (STT), laterality, surgeon, surgical procedures, follow-up surgeries and fluorescein stain results were manually evaluated. Results were captured in Excel and statistical analysis was performed in “R”. Patients were excluded if they had confounding pathology that may have affected healing post-operatively. Results: 441 unique surgeries were identified for SCCED lesions and after exclusions were applied a total of 288 surgeries were included in the results. 240 dogs and 274 eyes made up these cases. French Bulldogs, Staffordshire Bull Terriers, Boxer dogs, and Labrador Retrievers were the most common breeds (54.1%) presented for SCCED lesions. Male dogs (58.0%) were over-represented. The average age of the dogs were 8.3 years, and the average body weight was 19.3 kg. Affected and unaffected eyes had a mean IOP of 17.12 mmHg and 17.41 mmHg respectively. Affected and unaffected eyes had a mean STT of 25.59 mm/min and 22.49 mm/min respectively. The STT of affected eyes was significantly raised compared to unaffected eyes. The most reported clinical signs at initial presentation were keratitis, blepharospasm, lacrimation, and corneal oedema. Left or right eyes were equally likely to be affected. The contralateral eye was subsequently affected in 7.6% of dogs during the study period. Bilateral SCCED lesions were diagnosed in 10.4% of the dogs, and 4.9% of the eyes required a second follow-up surgery. The surgical outcome, between day 10-14 post-operatively, were not significantly different for SK and DBD. Both SK and DBD resulted in surgical success in 87.6% and 85.1% of eyes respectively. The main predictive variables for surgical procedure outcome were increased lacrimation at the initial examination and repeated follow-up surgeries for a single eye.