Exploring the Role of the Zeis Gland in Dry Eye Disease Associated with Demodex Blepharitis

PURPOSE: mite infestation of the eyelash follicles and associated sebaceous glands (the glands of Zeis) and is often associated with tear film instability and dry eye disease (DED). Information on the role of Zeis glands is limited. This study used surrogate Zeis gland secretions in healthy volunteers to evaluate whether Zeis gland secretions could potentially contribute to the tear film lipid layer. METHODS: The blinking status of each eye (partial or complete blinker) was assessed with interferometry. A surrogate Zeis gland secretion was applied with a moistened ophthalmic fluorescein strip across the center of the lower eyelid near the eyelash base. The presence of fluorescent dye in the tear film was evaluated at 2 and 5 min using a fluorescein angiography image acquisition system. RESULTS: Forty eyes (20 subjects) were enrolled; 31 (77.5%) partial blinkers, 4 (10.0%) complete blinkers, and 5 (12.5%) nonblinkers that did not blink during the interferometry assessment. Fluorescent dye was detected in the tear film of 18 (45.0%) eyes at 2 min and 24 (60.0%) eyes at 5 min, with similar proportions of partial blinker, complete blinker, and nonblinker eyes demonstrating a fluorescent signal. CONCLUSION: A surrogate Zeis gland secretion accessed the tear film in most eyes, suggesting that Zeis gland secretions may contribute to the tear film. In Demodex blepharitis, abnormal or reduced lipid production from the Zeis and/or meibomian glands may contribute to DED. Further research is needed to clarify the underlying mechanisms of DED in patients with Demodex blepharitis.