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Peripheral vision is usually spared since the pattern of loss typically involves a central or cecocentral scotoma, a visual field defect at or surrounding the point of fixation. This pattern can be revealed via visual field testing. Upon examination, the pupils usually demonstrate a normal response to light and near stimulation. In those who ...
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”.
Functional visual loss (FVL) also known as Functional vision loss or Nonorganic visual loss (NOVL) is a reduction in visual acuity or loss of visual field that has no physiological or organic basis. This disease can come under the spectrum of functional neurological disorder or somatic symptom disorder .
In 1934, the American Medical Association adopted the following definition of blindness: Central visual acuity of 20/200 or less in the better eye with corrective glasses or central visual acuity of more than 20/200 if there is a visual field defect in which the peripheral field is contracted to such an extent that the widest diameter of the ...
Beyond its literal sense concerning the visual system, the term scotoma is also used metaphorically in several fields, including neurology, neuropsychology, psychology, philosophy, and politics. The common theme of all the figurative senses is of a gap not in visual function but in the mind's perception, cognition, or world view.
Blue field entoptic phenomenon has the appearance of tiny bright dots moving rapidly along squiggly lines in the visual field. It is much more noticeable when viewed against a field of pure blue light and is caused by white blood cells moving in the capillaries in front of the retina. White cells are larger than red blood cells and can be ...
Illustration showing the position of the parietal lobe of the brain, the site of damage related to visual extinction. Visual extinction is a neurological disorder which occurs following damage to the parietal lobe of the brain. It is similar to, but distinct from, hemispatial neglect. Visual extinction has the characteristic symptom of ...
Visual acuity often remains stable and poor (around or below 20/200) with a residual central visual field defect. Patients with the 14484/ND6 mutation are most likely to have visual recovery. [8] Dominant optic atrophy is an autosomal dominant disease caused by a defect in the nuclear gene OPA1. A slowly progressive optic neuropathy, dominant ...