Changes in Ocular Surface Temperature and Blood Flow After Thermal Pulsation Treatment in Patients with Meibomian Gland Dysfunction: A Clinical Study

Background: Thermal pulsation (LipiFlow) warms the eyelids from the palpebral conjunctival surface. However, temperature and blood flow responses across multiple ocular-surface locations have not been systematically evaluated in a clinical cohort of patients with meibomian gland dysfunction (MGD). We examined changes in ocular surface temperature, blood flow and non-invasive tear break-up time (NIBUT) after LipiFlow in patients with MGD. Methods: Thirteen patients (3 men, 10 women; mean age, 64.9 ± 18.1 years) with MGD were included. The temperature and blood flow of the upper and lower eyelid skin and the palpebral and bulbar conjunctiva, along with the NIBUT, were measured before, 5 min after and 1 month after LipiFlow. The change from baseline was analyzed with Steel’s test. Results: All locations changed significantly 5 min after the treatment: the temperature rose by 1.13–1.21 °C, the blood flow increased to 1.24–1.45 times the baseline value, and NIBUT increased by 3.1 ± 2.7 s. At 1 month, temperature had returned to baseline at all locations, and blood flow had largely returned toward baseline, although bulbar conjunctival blood flow remained significantly elevated; NIBUT remained significantly longer than before treatment. Conclusions: Thermal pulsation warmed the ocular surface, including the palpebral conjunctiva where the meibomian glands are located. The improvement in tear film stability persisted for 1 month despite the largely transient temperature and blood flow responses.