Background: Meibomian gland dysfunction (MGD) is one of the possible conditions underlying ocular surface disorders (OSD). Prevalence of MGD in dogs affected by OSD has not yet been reported. We aimed to evaluate the prevalence of MGD among OSD canine patients, which had been assessed by non-contact infrared meibography and interferometry, and to identify MGD associated factors that might guide its diagnosis. Medical records of canine patients examined for OSD between 2016 and 2019 were reviewed. The frequency of MGD was evaluated within different categories (skull conformation, gender, eye and STT-1). The putative MGD risk factors and frequency of MGD within grades of interferometry were evaluated in a regression analysis model and reported as odd ratios (ORs).
Results: One hundred fifty eyes from 81 dogs with OSD were included with median age 75 months (range 3-192) and female representation with 52%. MGD was present in 70% of the examined eyes. MGD risk was higher in males ORadj = 3.015 (95% CI: 1.395-6.514) (P = 0.005) and older patients ORadj = 1.207 (95% CI: 1.081-1.348) (P = 0.001). No significant differences were found between left and right eyes (P = 0.66) or between the two types of skull conformation (P = 0.477) and MGD presence. MGD was associated to the lowest lipid layer (LL) thickness, as assessed by interferometry (grade 0) OR = 16.00 (95% CI: 2.104-121.68) (P < 0.001). STT values were not significantly associated with the presence of MGD (P > 0.05).
Conclusions: MGD is a common underlying pathology in OSD. Being male and higher age are risk factors for MGD. An interferometry grade 0 may guide OSD diagnosis towards MGD.
Keywords: Canine; Interferometry; Lipid layer; Meibography; Meibomian gland dysfunction; Ocular surface disorder; Tear film.