modern variation and evolutionary change in the hominin eye orbit

volume (r = -0.568), which means that high and narrow orbits are smaller in size thanlower more rectangular ones (Brown & Maeda, 2004). These authors also show that astrong positive relationship exists between supraorbital breadth and orbital volume (r =0.88), and between facial prognathism and orbital volume (r = 0.83), which indicates thatas faces become narrower and more orthognathic, respectively, the amount of spacewithin the orbit decreases. Reduction in the size of these features and in association withthe orbital margins becoming taller and more rounded throughout the Chinese Neolithicindicates that the orbits also diminish in size during this period (Brown & Maeda, 2004).Change in orbital morphology throughout the East Asian Holocene, andparticularly in relation to shape and volumetric modification associated with othercraniofacial trends, may impact visual acuity in groups that undergo such changesthrough time. Although Brown and Maeda (2004) observe temporal size and shapechange in the orbits of this East Asian sample, they do not address the issue of vision inthe functional sense, but do point out that “If it is the total volume occupied by theeyeball, extraocular muscles, nerves and blood supply which are important, rather thanjust the size of the eyeball, then there would need to be some functional compensation forany significant reduction in orbit length and volume” (Brown & Maeda, 2004 pg. 38).This raises an important question concerning the role of the orbit in maintainingkeen eyesight, and how changes in this feature may impact vision, particularly due to itslocation between a retracting lower face and expanding neurocranium throughouthominin evolution. The orbits circumscribe a number of different soft tissue componentsand the relationship among them changes throughout life. Modification to the timing orrate of growth in these various cranial, lower facial, and orbital features during ontogeny23