Glaucoma as a Neurodegenerative and Inflammatory Disease

Glaucoma is a neurodegenerative disease that leads to irreversible loss of vision through degeneration of the retinal ganglia cells (RGCs). Glaucoma is one of the most frequent causes of blindness in the world. Intraocular pressure is the main risk factor for the occurrence and development of this disease. Treatment is largely based on reducing internal optical pressure. However, some patients may deteriorate or become blind, despite normal or reduced internal optical pressure. The pathophysiological details are still unclear. Neuroinflammatory processes are also apparently an additional cause. In principle, innate or local responses of the adaptive immune system can be distinguished. The reaction of the innate immune system, particularly the local microglial cells, has long been studied. The macroglia with the astrocytes and Muller cells and their homeostatic effects have also long been known. On the other hand, it has long been thought that the retina with its RGZs was inert to adaptive immunological reactions - due to the function of the blood brain barrier. However, this system may be disturbed by antigen presentation, leading to a reaction of the adaptive immune system, with B cell and T cell responses. In this context, the key proteins are presumably heat shock proteins. We now know that neuroinflammation is important in glaucoma, as in other neurodegenerative diseases. It is important to increase our understanding of these phenomena. In this review article, we present our current knowledge of the role of the micro- and macroglia, the adaptive immune system, and the heat shock proteins.