A device intended to be placed over closed eyes to apply heat/steam for the treatment of meibomian gland dysfunction (MGD), dry eye syndromes, blepharitis (inflammation of the eyelid), and other related ocular conditions. It is typically in the form of a mask-shaped fabric envelope which either: 1) contains a heat-retaining substance intended to be heated in a microwave oven prior to use; or 2) includes an envelope(s) filled with a material that produces an exothermic chemical reaction when activated. This is a single-use device.