C3 and age-related macular degeneration: While only very moderate changes in complement expression were observed in early AMD for retinal cell types, our choroidal scRNA-seq findings demonstrated increased expression of the secreted complement components CFI, C1R, FCN3, CFH, C3, C7 and SERPING1. C3 was increased in fibroblasts (2-fold) and pericytes (1.3-fold) and C7 was increased 3-fold in fibroblasts and 1.8-fold in pericytes.