Meibomian Gland Dysfunction (MGD), as Diagnosed by Non-Contact Infrared Meibography, in Dogs with Ocular Surface Disorders (OSD): A Retrospective Study.

Abstract

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.

An investigation into the development of qualitative tear film disorders in dogs following cryoepilation for distichiasis

“…The current study found a TFBUT difference of 4.3 s between the treated group and the control group, and so, the relative increased presence of brachycephalic animals in the treatment group was unlikely to be significant enough alone to cause this vastly larger discrepancy in TFBUT values observed in the treated group. In addition, no differences have previously been identified for meibography parameters between brachycephalic and non‐brachycephalic dogs 15 . Therefore, in the current study the reference population was still a reliable comparison group, irrespective of the differences noted in skull conformation between groups.…”

“…In addition, no differences have previously been identified for meibography parameters between brachycephalic and nonbrachycephalic dogs. 15 Therefore, in the current study the reference population was still a reliable comparison group, irrespective of the differences noted in skull conformation between groups.…”

The pandemic of ocular surface disease in brachycephalic dogs: The brachycephalic ocular syndrome

“…Advancing age is known to negatively impact ocular surface homeostasis in humans, affecting all components of the lacrimal functional unit 56 . Similar changes are also reported in brachycephalic dogs, 7,23,49,52,57,58 although further research is needed to better characterize ocular surface physiology in older animals. In turn, this knowledge would help veterinarians and pet owners to slow down or prevent ocular surface pathology in aging brachycephalic dogs.…”

“…For every additional year of life, the risk for dogs to develop KCS or corneal pigmentation each increases by 10%, 7 while the risk to develop MGD increases by 20% 52 . The latter is supported by a study that examined 46 Shih Tzus and noted that MGD was more common in the middle‐aged and old‐aged groups compared with the juvenile group 49 .…”

“…The tear film is composed of a lipid layer that is produced by the meibomian glands, an aqueous layer that is produced by the lacrimal glands, and a mucin layer that contains the mucus produced by the conjunctival goblet cells, as well as the glycocalyx mucins of the corneal epithelial cells 46 . Problems in one or more of these layers could lead to a variety of forms of dry eye disease (DED) and they have been investigated and described with special interest in brachycephalic dog breeds 23,27,47–52 …”