Device for packaging and dispensing drops of a substance for ophthalmic use, generally fluid, semi-fluid or in suspension, emulsion or oily solution, comprising a dispensing accessory (7) with a first valve (5) made of an elastomer material that allows the substance to pass through when the dispensing accessory (7) is stressed, without allowing outside air to pass through in the opposite direction when the dispensing accessory (7) is relaxed, characterized in that the first valve (5) is covered by a layer of Parylene.
