Effects of Eyelid Warming Devices on Tear Film Parameters in Normal Subjects and Patients with Meibomian Gland Dysfunction

Purpose: To evaluate the effects of commercially available eyelid warming devices on ocular temperatures, tear film function, and meibomian glands in normal subjects and patients with meibomian gland dysfunction (MGD). Methods: Ten healthy volunteers were enrolled to evaluate the effects of a single warming and of repeated warming for 2 weeks. Ten MGD patients were enrolled for evaluation of repeated warming over 1 month. Two non-wet (Azuki no Chikara, Eye Hot R) and three wet (hot towel, Hot Eye Mask, Memoto Este) devices were compared in a masked manner. Visual analog scale (VAS) score for ocular symptoms, tear film breakup time (TFBUT), meibum grade, temperatures (eyelid skin, tarsal conjunctiva, central cornea), Schirmer test value, and meibomian gland area were measured before and after warming application. Results: The single application of the five warming devices improved the VAS score, TFBUT, and ocular temperatures. In the repeated warming application, Azuki no Chikara as a representative non-wet warming device induced a stable and significant improvement in TFBUT and increased the tarsal conjunctival temperature and meibomian gland area in both normal subjects and MGD patients. It also improved meibum grade in MGD patients. Conclusion: Our results suggest that repeated eyelid warming with a non-wet device improves tear film function in normal individuals and may have beneficial effects on both tear film and meibomian gland function in MGD patients.