An optical element for transmitting radiation includes: a first surface region surrounding an optically used area of the optical element; and a second surface region that adjoins the first surface region. A circumferential edge is formed between the first and second surface regions. The optical element further includes a one-piece film which covers the first surface region, the edge and the second surface region. The film includes a hydrophobic material at least on its side facing away from the first and the second surface regions. An optical assembly includes at least one such optical element. A method produces such an optical element.