C3 and age-related macular degeneration: Specific alteration and/or dysregulation of innate immune system are observed in AMD eyes mainly at the level of complement pathway elements, such as complement components C3a and C5a, C5 and C5b-9 terminal complement complex, complement regulators or inhibitors (i.e., CFH, vitronectin, and clusterin), CR1, MCP, and DAF, but also at the level of C-reactive protein [61–68].