from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. hemianopsia
from The Century Dictionary and Cyclopedia
- n. Same as hemianopsia.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. blindness in one half of the visual field of one or both eyes
Sorry, no etymologies found.
When the posterior part of the capsule is involved, there are, in addition, hemianæsthesia and hemianopia, and sometimes disturbances of hearing, smell, and taste.
Lesions implicating the cortical centre for sight in the occipital lobe give rise to hemianopia -- that is, loss of sight in the lateral halves of the fields of vision of both eyes -- colour-blindness, subjective sensations of light and colour, and other eye symptoms.
The optic tract, which crosses the crus, may also be affected, and hemianopia result.
In at least 22 states and many other countries, people with hemianopia are prohibited from driving because they do not meet the visual field requirements for licensure.
They also found a large variability in blind-side detection rates among the individuals with hemianopia (from 6% to 100%) with the lower rates found among the older subjects.
She and Peli believe the Schepens study, because it was conducted in the safety of a driving simulator over a longer period of time and "miles" than a typical "on-road" study, provides new insights into detection failures of drivers with hemianopia.
These results, published in the November 2009 issue of Investigative Ophthalmology and Visual Science, fly in the face of some recent on-road studies that have found most people with hemianopia safe to drive.
Although overall most subjects with hemianopia had detection rates that seem incompatible with safe driving, Bowers cautions that "the relationship of our simulator detection performance measures to on-road performance has yet to be established, another reason to treat each person with hemianopia individually as they seek approval to get back on the road."
Peli and his research team compared 12 subjects with hemianopia to 12 visually normal people, matched by age, sex, and years of driving experience.
The next step for the team is to determine whether an optical aid that expands the visual field - peripheral prism (expansion prism EP) glasses - might be a useful device for drivers with hemianopia.