Visual field

The region of space visible to an eye or pair of eyes while gaze is fixed. Its extent and sensitivity vary across directions and retinal locations.

Retinotopy: The orderly mapping of locations in visual space onto locations in the retina and visual brain. Each point in the visual field corresponds to a retinal location, though the mapping is uneven.
Visual angle: The angle an object subtends at the eye, determined by its size and distance. Visual-field locations are commonly measured as angular distances from fixation.
Perimetry: The measurement of visual sensitivity at locations across the visual field. It maps field extent and detects regions of reduced or absent sensitivity.
Field of view: The angular extent of a scene captured or displayed by an optical system. Unlike the visual field, it describes an instrument’s or display’s coverage, not human seeing.
Fovea: A small central retinal region specialized for high-acuity vision. The visual field around fixation receives its greatest spatial resolution through the fovea.
Fixation (visual): A period when the eyes are directed at a relatively stable point. The field is usually charted relative to the point of fixation.
Visual field test: A clinical examination that measures responses to visual stimuli at selected locations. This is the practical procedure used to chart a person’s field.
Peripheral vision loss: Reduced or absent sensitivity in outer regions of the visual field. It is a deficit within the field, not another name for the whole visible region.
Peripheral vision: Vision mediated by retinal regions outside the central fovea. It covers much of the visual field but detects detail less precisely than central vision.
Retina: The light-sensitive neural tissue lining the back of the eye. The retina receives the image corresponding to the visible region of space.

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