Thealoz Duo Gel works by adding moisture to hydrate and lubricate the surface of the eye, as well protecting the cells of the cornea and conjunctiva, giving resistance to dryness. This product is a dual combination of trehalose and hyaluronic acid. It protects, hydrates and lubricates the eyes for treatment of moderate to severe dry eye syndrome: Provides immediate comfort that lasts all day long and relief from the symptoms of dry eyes. It also soothes discomfort, stinging sensation, foreign body or irritation of the eyes caused by wind, smoke, pollution, dust, sunny or cold conditions, dry heat, air conditioning, plane journeys and long hours working in front of a computer screen.