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In human vision, the useful field of view (or UFOV) is the visual area from which information can be extracted without eye or head movements. [1] UFOV size generally decreases with age, [ 2 ] most likely due to decreases in visual processing speed, reduced perception, and increased susceptibility to distraction.
The Posner cueing task, also known as the Posner paradigm, is a neuropsychological test often used to assess attention. Formulated by Michael Posner, [1] it assesses a person's ability to perform an attentional shift. It has been used and modified to assess disorders, focal brain injury, and the effects of both on spatial attention.
This type of perimetry is the most commonly used in clinical practice, and in research trials where loss of visual field must be measured. [4] However, the sensitivity of white-on-white perimetry is low, and the variability is relatively high; as many as 25–50 percent of the photoreceptor cells may be lost before changes in visual field ...
A key property of visual attention is that attention can be selected based on spatial location and spatial cueing experiments have been used to assess this type of selection. In Posner's cueing paradigm , [ 4 ] the task was to detect a target that could be presented in one of two locations and respond as quickly as possible.
Testing the visual fields consists of confrontation field testing in which each eye is tested separately to assess the extent of the peripheral field. Normal visual field of a right eye. To perform the test, the individual occludes one eye while fixated on the examiner's eye with the non-occluded eye.
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"; [1] in ophthalmology and neurology the emphasis is mostly on the structure inside the visual field and it is then considered “the field of functional capacity obtained and recorded by means of perimetry”.
The visual field index (VFI) reflects retinal ganglion cell loss and function, as a percentage, with central points weighted more. [21] It is expressed as a percentage of visual function; with 100% being a perfect age-adjusted visual field and 0% represents a perimetrically blind field.
Peripheral vision of the human eye Field of view of the human eye. Peripheral vision, or indirect vision, is vision as it occurs outside the point of fixation, i.e. away from the center of gaze or, when viewed at large angles, in (or out of) the "corner of one's eye". The vast majority of the area in the visual field is included in the notion ...