Hylo Tear Preservative Free Eye Drops (7.5ml). The surface of your eye is covered by a thin layer of tears, called the Tear Film which protects, nourishes and lubricates the eye.. Tears are produced by several systems, and if any part of these systems break down, it can result in a reduced quality or quantity of tears. Tear replacement with eye drops is traditionally considered a mainstay of Dry Eye management.. HYLO-Tear® contains a natural occurring substance called Sodium Hyaluronate which replenishes the tear film. At a concentration of 0.1% it offers effective relief for moderate dry eyes and contact lens irritation.