Thealoz Duo Gel (30). Thealoz Duo Gel contains trehalose 3%, sodium hyaluronate 0.15% and carbomer 0.25% in a preservative free gel formulation. Trehalose helps protect corneal cells from the osmotic stress of a dry eye environment, by regulating the movement of water across cell membranes, stabilising the lipid bilayer and preventing the denaturation of proteins under osmotic stress conditions. Trehalose enhances TFEB (Transcription factor EB) activity, a key regulator of autophagy. In this way, cell renewal is promoted and apoptosis and the associated inflammation is reduced.. Sodium hyaluronate adds moisture by retaining water to hydrate and lubricate the surface of the eye. Trehalose is a clinically proven bioprotective gel indicated for treatment of moderate to severe dry eye disease, providing osmoprotection and bioprotection for cells on the corneal surface.1-6 The viscosity of the gel formulation increases residency time in the eye, making it particularly suitable for night time use.. Products containing preservatives can cause ocular surface toxicity, leading to inflammation and cell death. Using preservative-free eye drops supports the health of the ocular surface.