title: Human rather than ape-like orbital morphology allows much greater lateral visual field expansion with eye abduction.
abstract: While convergent, the human orbit differs from that of non-human apes in that its lateral orbital margin is significantly more rearward. This rearward position does not obstruct the additional visual field gained through eye motion. This additional visual field is therefore considered to be wider in humans than in non-human apes. A mathematical model was designed to quantify this difference. The mathematical model is based on published computed tomography data in the human neuro-ocular plane (NOP) and on additional anatomical data from 100 human skulls and 120 non-human ape skulls (30 gibbons; 30 chimpanzees / bonobos; 30 orangutans; 30 gorillas). It is used to calculate temporal visual field eccentricity values in the NOP first in the primary position of gaze then for any eyeball rotation value in abduction up to 45° and any lateral orbital margin position between 85° and 115° relative to the sagittal plane. By varying the lateral orbital margin position, the human orbit can be made "non-human ape-like". In the Pan-like orbit, the orbital margin position (98.7°) was closest to the human orbit (107.1°). This modest 8.4° difference resulted in a large 21.1° difference in maximum lateral visual field eccentricity with eyeball abduction (Pan-like: 115°; human: 136.1°).
authors.affiliation: 1] Inserm, U 1075 COMETE, Avenue de la côte de nacre, Caen, 5 Avenue de la côte de nacre, 14033 Caen cedex 9, France [2] Department of Ophthalmology, CHU de Caen, Avenue de la côte de nacre, 14033 Caen cedex 9, France [3] Medical School, Unicaen, pôle des formations des recherches en santé, 2 rue des Rochambelles, CS 14032, 14032 Caen cedex, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Denion
authors.affiliation: 1] Inserm, U 1075 COMETE, Avenue de la côte de nacre, Caen, 5 Avenue de la côte de nacre, 14033 Caen cedex 9, France [2] Medical School, Unicaen, pôle des formations des recherches en santé, 2 rue des Rochambelles, CS 14032, 14032 Caen cedex, France [3] Department of Otolaryngology - Head &Neck Surgery CHU de Caen, Avenue de la côte de nacre, 14033 Caen cedex 9, France [4] Anatomy Laboratory, pôle des formations des recherches en santé, 2 rue des Rochambelles, CS 14032, 14032 Caen cedex.
authors.forename: Martin
authors.initials: M
authors.lastname: Hitier
authors.affiliation: Cleverest Code, 24 place Etienne Pernet, 75015 Paris, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Levieil
authors.affiliation: 1] Department of Ophthalmology, CHU Pontchaillou, 2 rue Henri Le Guilloux, 35033 Rennes Cedex 9, France [2] Université de Rennes 1, 2 rue du Thabor CS 46510, 35065 Rennes cedex, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Mouriaux
mesh_terms: D000818:Animals; D005133:Eye Movements; D015186:Hominidae; D006801:Humans; D008962:Models, Theoretical; D009915:Orbit / Q000033:anatomy & histology*; D014794:Visual Fields