The central mechanism of dry eye according to recent consensus is caused by the instability of the tear film, which produces inflammatory and hyperosmolar processes and is associated with alteration of physical and neurosensory mechanisms. It is therefore essential to identify the role of the tear film and the pathological mechanisms involved, to assertively select treatments aimed at reestablishing tear homeostasis.
Currently the treatment is directed not only in the use of artificial tears, but in selecting the properties derived from these that replace the altered film; for this reason hypoosmolar tear substitutes, or based on antioxidants, polysaccharides or secretagogues represent the main treatment.
Another objective of dry eye therapy is protection against the epithelium, necessary to interrupt the vicious cycle suffered by pro-inflammatory cytokines produced during epithelial damage. The protective physical and biological characteristics of some tears have been identified as a potential treatment to protect epithelial damage. Aloe Vera and Trehalose have been indicated as therapeutic tools, capable of interfering with associated cellular metabolic dysfunction and controlling inflammation.
Hyaluronic acid is considered an essential component in tear substitute formulations, where it increases hydration and viscosity, improves retention time and optimizes hydration and lubrication of the ocular surface. There are several formulations present on the market.
Likewise, the use of tear substitutes with a medium viscosity formulation stabilizes the tear film and the complement with resolvins and antioxidant products provides tear balance and stability in the BUT. The new products provide hypoosmotic ingredients that regulate osmolarity. Current research links clinical findings and molecular biological finding to new eye lubrication targets