Molecular biomarkers in primary open-angle glaucoma: from noninvasive to invasive

Glaucoma, the first cause of irreversible blindness worldwide, is a neurodegenerative disease characterized by the progressive loss of retinal ganglion cells. There are different subtypes of glaucoma, all expression of a common optic neuropathy; primary open-angle glaucoma (POAG) is the most diffuse subtype in western countries. To date, unfortunately, several questions still remain unsolved in the glaucoma management, such as the availability of powerful methods for screening high-risk populations, early diagnosis, timely detection of damage progression, and prediction of response to therapy. Over the last years, biomarkers have gained immense scientific and clinical interest to solve these issues, with countless molecules that have been candidate as potential biomarkers. In the present review, we summarize the current knowledge about the most robust molecular biomarkers proposed in POAG, distinguishing noninvasive from minimally invasive, and invasive biomarkers, according to the procedure adopted to collect fluid samples.