Methods for forming optical articles with antireflective nanostructured (ARN) surfaces. An aluminum layer is deposited or otherwise applied to the cavity of an injection mold tool. Sequential chemical treatments such as anodization and etching steps form an 5 ARN mold texture on the interior surface of the cavity. The ARN mold texture is a negative of a desired surface texture of the article. During injection molding, the desired ARN surface is thereby produced in the optical article.