Hemianopia is the loss of half the field of vision on the same side in both eyes.
Eye research charity Fight for Sight is partnering with the Stroke Association to test the effectiveness of a treatment for ‘retraining’ the eyes for people who experience a loss of vision after stroke. The study hopes to establish a new standard of care for stroke survivors and save the NHS money.
About one third of patients who have suffered a stroke end up with low vision, losing up to half of their visual field. This partial blindness was long considered irreversible, but recent studies have shown that vision training after optic nerve and brain damage can help restore or improve vision. A new study published in the journal Clinical Neurophysiology reports on key mechanisms of vision restoration: attention.
Vision scientists may have discovered how to reduce pedestrian collisions in crowded and chaotic open space environments like bus terminals, shopping malls and city plazas involving individuals with partial blindness.
Researchers from the Schepens Eye Research Institute of Massachusetts Eye and Ear and Harvard Medical School have designed three new eyeglasses using high-power prisms to optimally expand the visual fields of patients with hemianopia, a condition in which the visual fields of both eyes are cut by half.
People who have lost some of their peripheral vision, such as those with retinitis pigmentosa, glaucoma, or brain injury that causes half visual field loss, often face mobility challenges and increased likelihood of falls and collisions.
A diagnosis of hemianopia, or blindness in one half of the visual field in both eyes as the result of strokes, tumors or trauma often means the end of driving.
Scientists know that vision restoration training (VRT) can help patients who have lost part of their vision due to glaucoma, optic nerve damage, or stroke regain some of their lost visual functions, but they do not understand what factors determine how much visual recovery is achieved.
Results from a crossover trial confirm anecdotal reports that patients with homonymous hemianopia benefit from wearing peripheral prism glasses.
More than a million Americans suffer from hemianopia, or blindness in one half of the visual field in both eyes as the result of strokes, tumors or trauma. People with hemianopia frequently bump into walls, trip over objects, or walk into people on the side where the visual field is missing.
The visual information from eyes is sent into the brain unconsciously even if you are not aware. One of examples of unconscious seeing is a phenomenon of "blindsight" [Subjects have no awareness, but their brains can see] in subjects with visual impairment, caused by the damage of a part of the brain called the visual cortex.
Patients who are blind in one side of their visual field benefit from presentation of sounds on the affected side. After passively hearing sounds for an hour, their visual detection of light stimuli in the blind half of their visual field improved significantly.
It has long been thought that blindness after brain lesions is irreversible and that damage to the optic nerves leads to permanent impairments in everyday activities such as reading, driving, and spatial orientation. A new study published in Elsevier's Brain Stimulation suggests that treating such patients with low levels of non-invasive, repetitive, transorbital alternating current stimulation (rtACS) for 10 days significantly reduces visual impairment and markedly improves vision-related quality of life.
Schepens Eye Research Institute scientists have found that--when tested in a driving simulator--patients with hemianopia (blindness in one half of the visual field in both eyes) have significantly more difficulty detecting pedestrians (on their blind side) than normally sighted people. 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.
In a study of specially designed peripheral prism glasses for hemianopia patients (blinded in half the visual field in both eyes), scientists found that two-thirds of patients continued to wear the glasses at the end of the study period and beyond, indicating a high level of success.
Columbia University Medical Center researchers have demonstrated using functional magnetic resonance imaging (fMRI), that brain activity was increased in stroke and traumatic brain injury survivors who underwent Vision Restoration Therapy (VRT), a rehabilitative treatment that helps these patients recover lost vision.