Tears Naturale® II soothes and moisturizes your dry, sensitive eyes just like your own tears. Tears Naturale® II contains POLYQUAD®preservative, recommended by doctors as being one of the most gentle on the eye. Store brand eye drops and even some national brands are still using a preservative called BAC (benzalkonium chloride), which has been shown to be harsher to the surface of the eye with frequent use.