The meibomian glands are tiny oil glands along the edges of your eyelids. They produce a protective oily layer that prevents your tears from evaporating too quickly. When these glands become blocked (a condition called Meibomian Gland Dysfunction or MGD), you may experience dry, gritty, burning, or watery eyes. Meibomian gland massage helps express the thickened oil and restore natural tear function.