C5AR1 and age-related macular degeneration: The C5a/C5aR pathway is known to be involved in the pathogenesis of various retinal diseases, including uveoretinitis [23] and AMD [38, 39] through (a) C5a-mediated recruitment of circulating immune cells [39] and (b) C5a-induced inflammatory responses in macrophages [23] and RPE cells [40].