There are significant differences in the ocular manifestations of Apert and Crouzon syndromes. Here, we present qualitative and quantitative data about the oculo-orbital region to demonstrate these differences. Although ocular protosis and hypertelorism characterize both disorders, the nature of the orbital dystopia differs. In Crouzon syndrome, ocular proptosis is primarily caused by retrusion of the lateral and inferior orbital margins with a very short orbital floor. In Apert syndrome, the eyeglobe actually protrudes in relation to the cranial base and to the orbit, probably resulting from marked protrusion of the lateral orbital wall. The implications account for some of the differences encountered. Asymmetry is associated with Apert syndrome frequently. Exotropia is found in Crouzon syndrome, whereas the V pattern is more characteristic in Apert syndrome with divergent upgaze and esotropic downgaze. Subluxation of the eyeglobe is found in some cases of Crouzon syndrome but is not found in Apert syndrome. Optic atrophy found in approximately 20% of Crouzon syndrome patients is not characteristic of Apert syndrome. Structural alterations of the extraocular muscles have been associated with some cases of Apert syndrome, suggesting that ocular motility disturbances in Apert syndrome may not be caused solely by mechanical factors. Absence of the superior rectus and other extraocular muscles has been recorded. Furthermore, albinoid alterations of the fundus have also been associated with Apert syndrome.