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Technology for sensory impairments (vision and hearing)
Published in Alex Mihailidis, Roger Smith, Rehabilitation Engineering, 2023
J. A. Brabyn, H. Levitt, J.A. Miele
Visual acuity measures resolution for the small central zone of the visual field, but many common eye conditions affect other areas of the field. Retinitis pigmentosa causes a narrowing of the visual field or “tunnel vision,” even though acuity in the center may be quite good for a long time. Glaucoma also causes impairments in the outer or peripheral visual field. A stroke can sometimes cause a “hemianopia,” in which the individual can only see one half (left or right) of the visual field. In age-related macular degeneration, blind spots develop in or near the center of the field but are usually irregular in shape and location. Standard visual field tests may be able to map these “scotomas” crudely but testing by a skilled low vision practitioner can obtain a more accurate assessment of scotoma size, shape, and position.
Sensory System Alterations Following Occupational Exposure to Chemicals
Published in Lucio G. Costa, Luigi Manzo, Occupatinal Neurotoxicology, 2020
Alterations in visual function following carbon disulfide exposure were first observed during ophthalmological examinations.40,41 These old clinical reports described the severe loss of central vision (central scotoma), depressed sensitivity in the peripheral visual field (rod scotoma) and accompanying optic atrophy. In addition, blurred vision, impaired color vision and pupillary changes were reported.41-43 Moreover, electrophysiological analysis revealed that the light/dark ratio of the electrooculogram (EOG) was decreased and that the amplitude of the dark-adapted (rod or scotopic) and light-adapted (cone or photopic) electroretino-grams (ERGs) were decreased with only a slight decrease in latency.39,43-45 Long-term alterations in both the EOG and ERG were still observable in a four-year follow-up study.39 Moreover, high frequency hearing loss has been found in workers chronically exposed to carbon disulfide.46
Complexity and the Barriers to Agility
Published in Barry Cross, Simple, 2017
In many cases, this acknowledgment of significant complexity is a hunch or feeling, an expectation that we should be performing at a higher level, but we are not clear why we struggle. I refer to this as organizational scotoma. A scotoma is a blind spot. Physiologically, they can occur in your eye, blocking vision and your ability to see out of certain parts of your eye. Far more common (and relevant to this discussion) are psychological scotoma. French philosopher Henri Bergson once said that “the mind sees only what it is prepared to comprehend.” This means that your brain is making decisions about what it allows you to see or not see on a fairly regular basis, often as a result of a functional focus on one element of an operation while another is causing a larger issue.
Miracles, misconceptions and scotomas in the theory of solitary waves
Published in Geophysical & Astrophysical Fluid Dynamics, 2019
In medicine, a “scotoma” is a blind spot, an object in the field of vision that is unseen, invisible. Oliver Sacks applied this medical term to a “knowledge gap”, a selective blindness to a part of the scientific literature (Sacks 1990). For example, Tourette's syndrome, though discovered in the 1880s, was a medical scotoma until revived by Sacks' work with L-dopa.