C3 and glaucoma: In glaucoma, these proinflammatory microglia/macrophages and neurotoxic astrocytes produced proinflammatory cytokines (e.g., tumor necrosis factor (TNF), interleukin-1β (IL-1β), IL-6, and IL-12), chemokines (e.g., C-C motif chemokine ligand 2 (CCL2), C-X-C motif chemokine ligand 2 (CXCL2), and CXCL10), complement component (e.g., C1q, C3, and C4), reactive oxygen species (ROS), and nitric oxide (NO) to directly induce RGC death or amplify the retinal neuroinflammatory response [16].