3ml. Unique lipid layer replacement for he management of evaporative dry eye. Suitable for moderate to severe dry eyes. Hycosan Shield is a unique and innovative eye drop that contains a molecule brand new to the UK market. Hycosan Shield has a single ingredient, water, phosphate and Preservative free formulation for the management of evaporative dry eye and MGD. Evaporative dry eyes are caused by an unstable of deficient lipid layer of the tear film that affects almost 90% of dry eye sufferers. This product replaces the outer lipid layer of the tear film creating a shield and helps to indirectly re-establish the tearfilm aqueous layer by preventing evaporation. Increases tearfilm thinckness as well as lipid layer thickness over time. Comes in a convenient 3ml bottle for use on the go.