Hyaluronic acid (HA), a natural component of the tear film, is a well-established active
ingredient in artificial tears and has been reported to improve corneal and conjunctival
staining in patients with DED. Thealoz Duo (Laboratoires Thea, Clermont Ferrand, France) is a
novel artificial tear preparation containing two active ingredients: trehalose, a naturally
occurring disaccharide with anhydrobiotic functions in many organisms, and hyaluronate, a
widely distributed anionic glycosaminoglycan polysaccharide with lubricative and
water-retaining properties in biological systems. The purpose of the current study is to
investigate the effect of the Hyabak and Thealoz Duo in treatment of DED.