Evaluation of Corneal Ulcer Type, Skull Conformation, and Other Risk Factors in Dogs: A Retrospective Study of 347 Cases

Objective To investigate the incidence of corneal ulceration (CU) and establish risk factors for dogs referred to an academic referral hospital in Ontario, Canada. Animals Dogs (N = 1101). Procedure Type of CU, number of CU diagnoses, breed, skull conformation, weight, sex, neuter status, age, and comorbidities were analyzed for simple CU, spontaneous chronic corneal epithelial defects (SCCEDs), and complex CU. Complex ulcers were subdivided into deep, presence of keratomalacia, descemetoceles, and corneal lacerations and foreign bodies (CLFB). Results The inclusion criteria were met by 347 dogs and 754 served as a control population of non-corneal ulceration (NCU) cases. Complex ulcers predominated (n = 134; 38.5%), including deep (n = 41; 11.8%), with keratomalacia (n = 20; 5.7%), descemetocele (n = 59; 17.0%), and CLFB (n = 14; 4.0%). Shih tzus were most predominant for every ulcer type, except for boxers for SCCEDs. Brachycephalic breeds have 2.757 greater odds (P, 0.0001) of presenting for CU, and 2.695 greater odds (P, 0.0001) of having a complex CU. Each 1 kg decrease in body weight increased odds of CU diagnosis by 1.3%. Yearly increase in age augmented the odds of CU diagnosis by 8.9% (P, 0.0001); older dogs were more likely to have SCCEDs ( P = 0.0040) and keratomalacia (P = 0.0257). Comorbidities increased odds of repeat CU diagnosis (P = 0.0024). Dogs with diabetes mellitus (P = 0.0318) had higher odds of SCCEDs. Conclusion Skull conformation, age, body weight, and comorbidities were identified risk factors for CU. Clinical relevance Knowledge of risk factors will help veterinarians triage at risk demographics.