Assessment of meibomian gland morphology by noncontact infrared meibography in Shih Tzu dogs with or without keratoconjunctivitis sicca.

Objective: To investigate meibomian gland (MG) morphology by noncontact infrared meibography in Shih Tzu dogs with or without keratoconjunctivitis sicca (KCS).

Procedures: Fourteen eyes of 12 Shih Tzu dogs (mean age of 10.7 years, range of 7-13 years) presented to Yakumo Animal Hospital or Triangle Animal Eye Clinic from 2011 to 2017 with clinical signs and a Schirmer tear test (STT) result consistent with KCS (<10 mm/min) were examined. Twenty-eight eyes of 16 Shih Tzu dogs (mean age of 12.4 years, range of 8 to 15 years) with a STT > 15 mm/min served as healthy controls. Both groups of dogs underwent routine slitlamp biomicroscopy followed by noncontact infrared meibography of the upper eyelid with both desktop-type and mobile-type systems. Results Meibography revealed morphological abnormalities of MGs in 13 eyes of 11 dogs with KCS. The abnormalities included gland shortening in 64% and gland dropout in 64% of the 14 eyes in the KCS group. Morphological changes were also observed in MGs of 16 eyes of 10 dogs in the control group. These changes included shortening in 46% and dropout in 17.8% of the 28 eyes in the control group. Dropout was significantly more common in eyes with KCS than in control eyes (P < 0.01). Conclusions The frequency of MG abnormalities is increased in Shih Tzus with KCS compared with control animals. A reduced quality of the tear film associated with increased evaporation and reduced retention of tear fluid likely exacerbates the effects of a reduced tear volume in animals with aqueous deficiency.