MBL2 and retinal vein occlusion: CFB: complement factor B; CFD: complement factor D; CFI: complement factor I; CFH: complement factor H; MBL: mannose-binding lectin; VA: visual acuity; FAZ: foveal avascular zone; PERIM: perimeter of foveal avascular zone; CRT: central retinal thickness; ILM-IPL: inner limiting membrane-inner plexiform layer; SVD: superficial capillary plexus vessel density; DVD: deep capillary plexus vessel density; RVO: retinal vein occlusion