The goal of this article is to offer an overview of the current ocular lubricants, discuss the components of the various formulations, and emphasize the state of preservative usage in the treatment of anterior ocular surface disorders. In the past, the major components of ocular surface lubrication were based on different cellulose formulations that increased hydration. Lubrication advances have come from regions of the human body that require lubrication, such as the skeletal joints, as well as research into the utilization of natural components of tear fluid. These have resulted in unique changes to existing tear components, such as thiolated carboxymethyl hyaluronic acid, which generates crosslinking to mechanically improve ocular surface hydration retention duration. Other proteoglycans, such as lubricin, which has one of the lowest coefficients of friction in nature, combined with a lipopolysaccharide derivative of tamarind seed, might provide a novel delivery method for lubricants and medicines.
Ocular surface lubrication is gradually progressing from the usual use of cellulose-based solutions and gels to more sophisticated replacement with natural tear components. The advancements being made on other lubricating surfaces of the musculoskeletal system are also offering some insight into prospective applications on the ocular surface.