The TearScience Meibomian Gland Evaluator (by Tear Science) is a hand-held device that provides evaluation of Meibomian gland function. Meibomian gland function is evaluated by observing the glands through a slit lamp while pressure is applied, simulating the pressure of a deliberate blink.
For more information, see: TearScience Meibomian Gland Evaluator