Peripheral is from the root periphery (noun) and comes from the Greek word Peripheria and more closely means circumference, globular, rounded or spherical.  The prefix peri- is from this ancient Greek origin and has meanings such as round, around and roundabout, so that when it is combined in active description (adverb) you get meanings such as; to look around, to turn around, and to walk around.[1] There are some interesting words located around peripheral in the dictionary.  One in particular is periphrasis which is a roundabout or indirect way of speaking (or writing), now commonly referred to as rhetorical or rhetoric (circumlocution).[2] To look around and walk around are integral functions of peripheral vision, somewhat more than what appears in the corner of the eye.  If this can be related to the meaning of periphrasis in speech then peripheral vision can be termed a roundabout way of looking.

1. “Oxford English Dictionary (Online),” Oxford University Press,  www.oed.com/view/Entry/140847 (peri-, prefix).

2. Ibid.,  www.oed.com/view/Entry/141026 (periphrasis, n.).

MAK