Visual field
The term
visual field is sometimes used as a
synonym to
field of view, though they do not designate the same thing. The visual field is the
"spatial array of visual sensations available to observation in introspectionist psychological experiments" (J. Smythies [
1]), while field of view
"refers to the physical objects and light sources in the external world that impinge the retina". In other words, field of view is everything that (at a given time) causes light to fall onto the retina. This input is processed by the
visual system, which computes the visual field as the output.
The term is often used in
ophthalmology, where a
visual field test is used to determine whether the visual field is affected by diseases that cause local
scotoma or a more extensive
loss of vision.
Visual field loss may occur due to disease or disorders of the
eye,
optic nerve, or
brain. In humans, confrontational testing and other forms of
perimetry are used to detect and measure visual field loss. Different neurological difficulties cause characteristic forms of visual disturbances, including
hemianopsias (shown below
without macular sparing),
quadrantanopsia, and others.
|
Paris as seen with full visual fields |
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| Paris as seen with right homonymous hemianopsia |
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