Hylo Dual is a preservative free lubricating eyedrop formulated with high-molecular-weight sodium hyaluronate to increase viscosity, and Ectoine which helps stabilize the lipid phase of the tear film. Ectoine protects your eyes from allergens using a strong water-binding capacity. The water surrounding Ectoine is bound very compact and forms a physiologic barrier. This ‘shield’ of Ectoine and water protects cell membranes from contact with allergenic substances and against inflammatory responses to environmental stress (e.g., dehydration, hyperosmolar tears, UV radiation, or airborne allergens).