According to the best corrected visual acuity and the morphological changes of the macular fovea, responses to the neovascular age-related macular degeneration (nAMD) who receive anti-vascular endothelial growth factor (VEGF) therapy show large variability, including poor and non-responders. Various factors will be reviewed to account for poor and non-response to anti-VEGF therapy, such as the related susceptibility genes, factors related with the development of choroidal neovascularization and morphologic parameters, pharmacokinetics and tachyphylaxis. The future research should focus on comprehensive assessment of factors affecting the efficacy of anti-VEGF therapy to improve the therapeutic outcome of nAMD.