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.

Tear film breakup time and Schirmer tear test in normal dogs: Effects of age, sex, reproductive status, skull type, and nasolacrimal duct patency

“…It is defined as the time taken for the first dry spot of TF to appear on the cornea after a complete blink 1,3 . To evaluate the lipid layer and meibomian glands, interferometry and meibometry are recommended, respectively 3,5 …”

“…Brachycephalic breeds are prone to a wide variety of ocular problems, which mainly occur due to macroblepharon, lagophthalmos, skin folds, and low corneal sensitivity 5,9 …”

“…1,3 To evaluate the lipid layer and meibomian glands, interferometry and meibometry are recommended, respectively. 3,5 Currently, more than 197 breeds are registered by the American Kennel Club. Many of these breeds are brachycephalic dogs, such as Shih Tzu and Pekingese.…”

“…8,9 Brachycephalic breeds are prone to a wide variety of ocular problems, which mainly occur due to macroblepharon, lagophthalmos, skin folds, and low corneal sensitivity. 5,9 The purpose of this study was to compare TBUT and STT in brachycephalic and non-brachycephalic breeds and determine the effects of age, sex, reproductive status, skull type, and nasolacrimal duct (NLD) patency on STT and TBUT in dogs.…”

An Eye on the Dog as the Scientist’s Best Friend for Translational Research in Ophthalmology: Focus on the Ocular Surface

“…201 • Meibomian gland dysfunction is recognized in many canine patients with ocular surface disorders, affecting tear film stability in a similar manner than evaporative dry eye in human patients. 245 • Spontaneous symptoms of ocular irritation, conjunctival hyperemia and corneal scarring correlate directly with aqueous tear production, a parameter that is easily measured/quantified using a standard Schirmer tear test strip. • Multiple diagnostic tools used in humans can easily be applied in dogs (but not rodents) given the large size of the canine globe, 205,239 including tear osmometry, vital staining, strip meniscometry test, infrared meibography and corneo-conjunctival impression cytology.…”