Thealoz Duo is an eye drop solution that uses two active ingredients to provide better lubrication and greater relief from the symptoms of dry eye. The two factors combined are Trehalose (3%) and Hyaluronic Acid (0.15%). Trehalose naturally protects cell membranes from excessive dryness, oxidation and temperature. It protects the corneal epithelial cells from dehydration and protects the cells against the increased osmolality found in the tears of the affected eye.