Caroline A Blackie,1 Christy A Coleman,1 Edward J Holland,2  On behalf of the LipiFlow Study Group 1TearScience Inc., Morrisville, NC, 2Cincinnati Eye Institute, Edgewood, KY, USA Purpose: To evaluate the sustained effect (up to 1 year) of a single, 12-minute vectored thermal pulsation (VTP) treatment in improving meibomian gland function and dry eye symptoms in patients with meibomian gland dysfunction and evaporative dry eye.Methods: The prospective, multicenter, open-label clinical trial included 200 subjects (400 eyes) who were randomized to a single VTP treatment (treatment group) or twice-daily, 3-month, conventional warm compress and eyelid hygiene therapy (control group). Control group subjects received crossover VTP treatment at 3 months (crossover group). Effectiveness measures of meibomian gland secretion (MGS) and dry eye symptoms were evaluated at baseline and 1, 3, 6, 9, and 12 months. Subjects with inadequate symptom relief could receive additional meibomian gland dysfunction therapy after 3 (treatment group) and 6 months (crossover group).Results: At 3 months, the treatment group had greater mean improvement in MGS (P<0.0001) and dry eye symptoms (P=0.0068), compared to controls. At 12 months, 86% of the treatment group had received only one VTP treatment, and sustained a mean improvement in MGS from 6.4±3.7 (baseline) to 17.3±9.1 (P<0.0001) and dry eye symptoms from 44.1±20.4 to 21.6±21.3 (P<0.0001); 89% of the crossover group had received only one VTP treatment with sustained mean improvement in MGS from 6.3±3.6 to 18.4±11.1 (P<0.0001) and dry eye symptoms from 49.1±21.0 to 24.0±23.2 (P<0.0001). Greater mean improvement in MGS was associated with less severe baseline MGS (P=0.0017) and shorter duration of time between diagnosis and treatment (P=0.0378).Conclusion: A single VTP treatment can deliver a sustained mean improvement in meibomian gland function and mean reduction in dry eye symptoms, over 12 months. A single VTP treatment provides significantly greater mean improvement in meibomian gland function and dry eye symptoms as compared to a conventional, twice-daily, 3-month regimen. Early VTP intervention for meibomian gland dysfunction is associated with improved treatment outcomes. Keywords: meibomian gland dysfunction, dry eye, vectored thermal pulsation, LipiFlow®