['To investigate the influence of complement component C5a inhibition on laser-induced choroidal neovascularization (CNV) in mice using a C5a specific L-aptamer.', 'In C57BL/6 J mice CNV was induced by argon-laser, C5a-inhibitor (NOX-D20) was intravitreally injected in three concentrations: 0.3, 3.0, and 30 mg/ml. The unPEGylated derivate (NOX-D20001) was applied at 3.0 mg/ml; the vehicle (5 % glucose) was injected in controls. Vascular leakage was evaluated using fluorescence angiography, CNV area was examined immunohistochemically. Activated immune cells surrounding the CNV lesion and potential cytotoxicity were analyzed.', 'Compared to controls, CNV areas were significantly reduced after NOX-D20 injection at a concentration of 0.3 and 3.0 mg/ml (p\u2009=\u20090.042; p\u2009=\u20090.016). NOX-D20001 significantly decreased CNV leakage but not the area (p\u2009=\u20090.007; p\u2009=\u20090.276). At a concentration of 30 mg/ml, NOX-D20 did not reveal significant effects on vascular leakage or CNV area (p\u2009=\u20090.624; p\u2009=\u20090.121). The amount of CD11b positive cells was significantly reduced after treatment with 0.3 and 3.0 mg/ml NOX-D20 (p\u2009=\u20090.027; p\u2009=\u20090.002). No adverse glial cell proliferation or increased apoptosis were observed at effective dosages.'] Does intravitreal inhibition of complement C5a reduce choroidal neovascularization in mice?