Modeling the effect of facial topographies upon the visual field of humans and primates

Purpose: To establish a virtual device that can predict the effect of facial features on the visual field of humans and primates. Methods: Virtual masks were obtained from human subjects, and macaque, chimpanzee and baboon taxidermic specimens, and aligned with upright head orientation at the center of a virtual perimeter-like dome (radius = 50 m) developed with Cinema 4D. Virtual searchlights positioned at the masks' pupils were then allowed to 'paint' facial elements obstructing their path, and demarcate the unobstructed rays at the perimetric surface and on a virtual ground floor related to eye level. Searchlight positions along the human mask's pupillary axis were identified by maximum congruence to Goldmann visual field limits. Results: The human contours largely concur with large-stimulus isopters displaying the limiting role of the nasal ridge, and the relatively extended ventral and temporal limits. In contrast, the facial design of chimpanzees and baboons obstructs significant portions of the ventral foreground (> 2 m cf < 0.5 m in human), while there appear to be larger binocular overlaps (125 degrees in chimp cf 90 degrees in human). Conclusions: The model provides information on anatomical constraints for monocular and binocular visual field extensions including projection of the ventral field on a virtual floor.