Primary open-angle glaucoma: neuroendocrine-immune disorder?

Glaucoma is no longer simply viewed as a pathological process involving damage to the visual system by an elevated intraocular pressure (IOP). Mounting evidence suggests that primary open-angle glaucoma (POAG) may be associated with systemic disorders, mainly those related to the nervous system, endocrine system and immune system. It has been firmly established that the neuroendocrine system and immune system closely interact through mediators such as hormones, neuropeptides, neurotransmitters and cytokines. The neuroendocrine-immune system can synthesize and release these molecules, which in turn affect the activity of immune or neuroendocrine cells by binding to their receptors. In POAG patients, the alterations of the nervous, endocrine and immune systems observed in various studies have been linked to their POAG. Here, we hypothesize that the onset and development of POAG is closely associated with abnormalities in neuroendocrine-immune communication; thus, the interrupted homeostatic state might have a significant influence on the course of the disease. Based on the effects on the secretions of the aqueous humor, the inflow/outflow pathways of the neuroendocrine system, and the survival of retinal ganglion cells (RGCs) in the immune system, we propose that POAG is likely to be a consequence of a neuroendocrine-immune system disorder.