There is provided an optical module for microlithography. The optical module includes an optical element and a retaining device for holding the optical element. The optical element has (a) a main extension plane, in which it defines a radial direction R and a circumferential direction U, and (b) a free optical diameter and an overrun in the region of its outer periphery. The retaining device contacts the optical element in the region of the overrun, and is formed and/or contacts the optical element in such a manner that the overrun ratio, calculated from the overrun related to a minimum overrun necessary for the production of the optical element, is at most 1.5.