VIZhyal 0.4% is a sterile solution for ophthalmic use with a physiological pH, based upon a patented technology of cross-linking Hyaluronic Acid (HA) with Urea, therefore enhancing and improving the specific mechanical properties of native HA, resisting to hyaluronidase degradation much longer than native HA, thus with higher and prolonged lubricant and hydrating action than native HA.