The disclosure concerns to a process for manufacturing an optical element from glass, wherein a blank of glass is tempered, for example in such a way that the blank is cooler in its interior than on its exterior, wherein the tempered blank between a first mold and a second mold, which are moved towards one another to form a closed cavity, is press-molded, for example on both sides, to form the optical element, wherein the first mold and/or the second mold comprises an escape cavity slide which is compressed by the formation of a closed cavity by means of the first mold and the second mold as a function of the volume of the blank, so that, during press-molding, an additional edge which is dependent on the volume of the blank is formed with the optical element.