The patients will be treated with Thealoz Duo (at least 3 times daily) in one eye and with Hyabak (at least 3 times daily) in the other eye, based on randomization table. Both Hyabak and Thealoz Duo are preservative free. The doctors who examine the patients will not get any information about the choice of artificial tears in each eye. Besides the artificial tears, if necessary, the patients will receive other treatments, for instance, steroids, cyclosporine etc., according to their dry eye severity.
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.