All of the points of the physical environment that can be perceived by a stable eye at a given moment WordNet 3.0 & Open English WordNet

The visual field is "that portion of space in which objects are visible at the same moment during steady fixation of the gaze in one direction"; in ophthalmology and neurology the emphasis is on the structure inside the visual field and it is then considered “the field of functional capacity obtained and recorded by means of perimetry”. Wikipedia

The part of the field of view which can be perceived by the eye's retina Wikipedia Disambiguation

Total area or space visible in a person's peripheral vision with the eye looking straight forward Wikidata