A method for superposing a first ophthalmic lens having a first face and a second ophthalmic lens having a second face in order to build an optical assembly delimited by the first and second faces. The method includes detecting respective positions in space and shapes of the first and second ophthalmic lenses, by using at least one sensor, detecting a first reference point on the first ophthalmic lens and a second reference point on the second ophthalmic lens, based on these respective positions in space and shapes, and modifying the respective positions so as to superpose the first and second reference points.