OPTASE? Allegro Eye Drops is a preservative free lubricant that acts as a first line of defense to stop Environmental Irritants in their tracks. * OPTASE? Allegro Eye Drops is a a preservative free lubricant offering instant comforting relief from Environmental Irritants. * OPTASE? Allegro works with the natural tears to create a protective barrier from Environmental Irritants. * OPTASE? Allegro?? formulation including Hydroxyethyl cellulose lubricates and stabilizes the tear film and Ectoin?. * OPTASE? Allegro is clinically proven to alleviate dry eye symptoms and works in 30 seconds.