A device for packaging and dispensing drops of a product for ophthalmic use, generally fluid, semi-fluid or in suspension, emulsion or oily solution, comprising a dispensing accessory comprising a first valve made of elastomer material allowing passage of the product when the dispensing accessory is stressed without allowing outside air to move in the reverse direction when the dispensing accessory is released, characterized in that the first valve is covered with a layer of parylene, wherein the device comprises: - a container intended to contain the product and dispense it, the dispensing accessory being mounted on the container and the first valve allowing the product to exit the container when the dispensing accessory is stressed without allowing outside air to enter the container when the dispensing accessory is released, - a renewal and filtration assembly of the air entering the container after dispensing of a product portion or dose, comprising a second valve made of elastomer material and covered with a layer of parylene, allowing outside air to enter said container when the dispensing accessory is released without allowing the product or substantially the air contained inside the container to exit when the dispensing accessory is stressed, the second valve having a shape consisting of: o a substantially plane circular shape having two faces, a first face being turned towards the interior of the container and delimited by an outer rim, and o a protuberance (361, 362) extending over a central area of the circular shape delimited by an inner diameter (d), engaged with the circular shape, extending perpendicularly to the circular shape on either side of the circular shape, and/or the second valve having a substantially plane general circular shape delimited by an outer rim and is adapted to allow passage of the product: o by deformation at the level of a central area, the outer rim of the valve being held in position by forces applied on either side of the latter, or o by deformation of the outer rim, a central area of the valve being held in position by forces applied on either side of the latter, and/or wherein the first valve has a substantially plane general circular shape delimited by an outer rim and is adapted to allow passage of the product: - by deformation at the level of a central area, the outer rim of the valve being held in position by forces applied on either side of the latter, or - by deformation of the outer rim, a central area of the valve being held in position by forces applied on either side of the latter, and/or wherein the dispensing accessory is a dispensing accessory for calibrated drops comprising: - a flexible membrane whereof the stress causes dispensing of the product, - a metering chamber of the product delimited at least by: o a first portion of a periphery of a rigid core and o a part of elastically deformable flexible membrane located facing the first portion, the flexible membrane extending about the rigid core, the first valve made of elastomer material allowing the product to enter the metering chamber when the flexible membrane is stressed without allowing outside air to move in the reverse direction when the flexible membrane is released. - a container intended to contain the product and dispense it, the dispensing accessory being mounted on the container and the first valve allowing the product to exit the container when the dispensing accessory is stressed without allowing outside air to enter the container when the dispensing accessory is released, - a renewal and filtration assembly of the air entering the container after dispensing of a product portion or dose, comprising a second valve made of elastomer material and covered with a layer of parylene, allowing outside air to enter said container when the dispensing accessory is released without allowing the product or substantially the air contained inside the container to exit when the dispensing accessory is stressed, o a substantially plane circular shape having two faces, a first face being turned towards the interior of the container and delimited by an outer rim, and o a protuberance (361, 362) extending over a central area of the circular shape delimited by an inner diameter (d), engaged with the circular shape, extending perpendicularly to the circular shape on either side of the circular shape, o by deformation at the level of a central area, the outer rim of the valve being held in position by forces applied on either side of the latter, or o by deformation of the outer rim, a central area of the valve being held in position by forces applied on either side of the latter, - by deformation at the level of a central area, the outer rim of the valve being held in position by forces applied on either side of the latter, or - by deformation of the outer rim, a central area of the valve being held in position by forces applied on either side of the latter, - a flexible membrane whereof the stress causes dispensing of the product, - a metering chamber of the product delimited at least by: o a first portion of a periphery of a rigid core and o a part of elastically deformable flexible membrane located facing the first portion, the flexible membrane extending about the rigid core, o a first portion of a periphery of a rigid core and o a part of elastically deformable flexible membrane located facing the first portion, the flexible membrane extending about the rigid core,