abnormal Meibomian gland morphology abnormal Meibomian gland development MP:0013385 MPheno.ontology aberrant formation or incomplete differentiation of the sebaceous glands located at the rim of the eyelids inside the tarsal plate and responsible for the supply of meibum, an oily substance that prevents evaporation of the eye's tear film; in mice, meibomian gland development is initiated around E18.5 with the formation of an epithelial placode and mesenchymal condensation, similar to that observed in hair follicle development; invagination of the epithelium into the developing mesenchyme then continues from birth to about P3 with initial branching of the epithelial cord detected at P5; by P8 the developing meibomian gland shows extensive ductal branching and the formation of distinct acini with mature meibomian glands present by P15 or eyelid opening abnormal tarsal gland development