Unlike eye drops, only Nature's Tears EyeMist adds soothing natural moisture to the eye without flooding the tear film's Lipid Layer. The patented ultra-fine mist penetrates the tear film's Lipid Layer to add soothing moisture to the Aqueous (Water) Layer. 1. Lipid Layer: Thin top layer that lubricates eyelid and slows evaporation from Aqueous Layer. 2. Aqueous (Water) Layer: Thick middle layer that is 99% water. When the Aqueous Layer loses water/moisture, dry eye and discomfort may result. 3. Mucin Layer: Thin bottom layer that adheres the tear film to the corneal surface. EyeMist contains 100% Bio-Logic Aqua Tissue Culture Grade Water/Trade Secret, is pure, all-natural, pH-balanced and biocompatible with the natural tear film. The micron-mist instantly re-hydrates tear film while also moisturizing skin around the eyes and eyelids. Eye drops trap and seal moisture but do not add supplemental moisture to the tear film, only Nature's Tears EyeMist does. It offers safe and effective relief between eye drop applications.