The Prevalence of Corneal Disorders in Pugs Attending Primary Care Veterinary Practices in Australia

Pugs are highly predisposed to corneal disorders, such as brachycephalic ocular syndrome (BOS), due to their disproportionate skull, reduced corneal sensitivity and eyelid anomalies such as distichiasis, entropion and lagophthalmos. The risk of corneal disorders which cause significant suffering is substantial, prompting calls for international efforts to reduce their prevalence. While these debilitating conditions are also likely to be common in pugs in Australia, their prevalence and risk factors have not been reported. The anonymised electronic patient records (EPRs) of 1318 pugs attending 139 primary care veterinary clinics participating in VetCompass Australia (VCA) in 2017 were used to investigate the prevalence of ophthalmological pathologies and associated demographic risk factors. Pugs were diagnosed with overweight/obesity (prevalence: 20.2%, 95% confidence interval {CI}: 18.1-22.4) ophthalmological abnormalities (14.5%, 95% CI: 12.6-16.3), particularly corneal disorders (12.4%, 95% CI: 12-15.7), and other conditions. The most prevalent ophthalmological disorders were corneal ulcers (5.5%, 95% CI: 4.4-6.9), corneal pigmentation (3.6%, 95% CI: 2.8-4.8) and keratoconjunctivitis sicca (KCS) (3.3%, 95% CI: 2.5-4.5). The risk of all corneal disorders increased with age (odds ratio 1.11, 95% CI: 1.07-1.15), and corneal pigmentation, KCS and keratitis were more prevalent in older pugs (a median age of 7.6 years or older), while entropion, neovascularisation and ulcerative keratitis affected younger dogs (a median age of 3 years or under). The underlying BOS conformation defects, exophthalmos, lagophthalmos and distichiasis, and early signs of corneal damage should be identified through detailed examinations during primary care veterinary visits, and affected pugs should be removed from the breeding population and treated to reduce the severity and duration of their suffering.