[The tear biomarkers, as source of information for the ocular surface. the tears as mirror of the eye?].

he lachrymal film is the first element of the ocular optic ystem and fulfills important functions comprising mechanial and antimicrobial protection, ocular surface nutrition and eflective functions, among others. The formation and stabilty of the lachrymal film both in healthy and diseased eyes epend on the composition and physical properties of the tear. ne of the difficulties exhibited by ocular surface diseases is n overlap in clinic and exploration, partly due to the frequent oexistence of both factors in the same subject, which makes ts diagnosis and treatment more difficult. Numerous examles of this can be found in pathologies such as blepharitis, ry eye syndrome or ocular allergy. We cannot forget the muliplicity of situations in which the ocular surface is altered for atrogenic causes including glaucoma, cataract postop period, tc. In recent years the search of biomarkers for human disases has been highly successful due to the development of ncreasingly sensitive techniques in the field of genomics and roteomics. The description of these biomarkers will allow he scientific community to develop more reliable diagnostic ethods, to determine the intimate mechanisms of a disase, forecast its progression and get closer to therapeutic ptimization. Due to these advances in analysis techniques,