The present disclosure relates to an apparatus for determining the orientation of ophthalmic lenses (20, 22). The apparatus includes a recording device and a reference-frame unit that can be fitted onto a frame (14) while a patient is wearing it. Said frame has two half parts (11, 13) and a central bridge (15). The reference-frame unit includes a first element forming an arch (24) that has a central portion (26) indicated by a first reference mark (54), and a second element (56) indicated by a second reference mark (58), mounted on said frame. According to the disclosure, the apparatus includes two cameras (60,62) separated vertically from each other and pointing at the eyes from two angles of view (64, 66) and the two cameras (60, 62) enable two images of said reference-frame unit (24, 56) to be recorded simultaneously in order to evaluate the relative positions of the two reference marks (54, 58) and provide a value that represents the slope of said half parts (11, 13).
