A non-powered device intended to be placed over closed eyes to apply heat/steam and/or cold to the eyes 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 thermal-insulating substance intended to be heated in a microwave oven or cooled in a freezer prior to use; or 2) includes an envelope(s) filled with a material that produces an exothermic chemical reaction when activated. Some types have a non-pharmaceutical antimicrobial coating to reduce eye infection risk. This is a single-use device.