What are the Accessibility Guidelines for Reading with Hemianopia?
Vision loss caused by hemianopia results in a loss of reading ability as the eyes lose their visual functions. To minimize the visual neglect of the eyes, there are some methods:
- Use a larger font size: A larger font size makes it easier for individuals with hemianopia to read and process written content.
- Use clear and simple language: Avoid using complex or technical language, as this makes it more difficult for individuals with hemianopia to understand the content.
- Use a sans-serif font: Sans-serif fonts are easier to read for individuals with visual impairments.
- Use high contrast colors: Use high contrast colors, such as black text on a white background, to make the content easier to read.
- Use bullet points and short paragraphs: Breaking up content into smaller, digestible chunks makes it easier for individuals with hemianopia to read and process.
- Use images and graphics: Use images and graphics to support written content and help individuals with hemianopia better understand the information.
- Provide alternative formats: Offer alternative formats, such as audio or braille, for individuals with hemianopia who have difficulty reading written content.
What is Hemianopia?
- Hemianopia is a neurology-based visual impairment that results in low vision in one-half or quadrantanopia of the visual field.
- The loss of vision occurs in one eye or in both eyes and affects the right or left side of the visual field.
- Hemianopia disability is caused by a variety of medical conditions, including stroke, traumatic brain injury, and brain tumors.
- Hemianopia has a significant impact on an individual’s quality of life.
- Individuals with this condition can learn to adapt and function in their daily lives with proper support.
What is Homonymous Hemianopia?
Here are some facts about Homonymous Hemianopia:
- Homonymous hemianopia is a type of hemianopia that affects the same side of the visual field in both eyes.
- It is usually caused by damage to the optic tract or visual cortex in the brain, which disrupts the transmission of visual information.
- Individuals with homonymous hemianopia experience difficulty with visual tasks like reading, driving, and recognizing objects on the affected side.
- There are three types of homonymous visual field defects.
- Treatment for homonymous hemianopia involves visual rehabilitation and compensatory strategies to help individuals adapt to their visual impairment.
What is Heteronymous Hemianopia?
- Such as hemianopic dyslexia and/or hemianopic alexia, Hemianopia can lead to damage in the areas of the brain responsible for processing reading text.
- However, due to the visual field defect or blind spot, patients with this condition are unable to plan and execute proper reading saccades.
- Additionally, patients with hemianopia face difficulty while reading horizontally and performing reading saccades into the blind hemifield.
- Moreover, hemianopic patients have difficulty seeing follow-up words in their parafoveal vision, which ultimately reduces optokinetic movement and makes reading extremely challenging.
What are the Symptoms of Hemianopia?
Here is a list of Hemianopia symptoms:
- Loss of coordination on the affected sideVisual disturbances like double vision, dim vision, or impaired night vision
- Not noticing objects on the affected side
- Problems with reading performance, including reduced reading speed
- Hemifield slide phenomenon
- Visual search disorders and other perceptual problems
- Pure alexia (selective reading impairment caused by brain damage that occurs without other language deficits)
What are the Causes of Hemianopia?
The visual cortex resides in the occipital lobe of the brain in the primary cortical region and aids in the conscious processing of visually obtained data. There are multiple causes of hemianopia, including but not limited to:
- Traumatic brain injuries (TBI) sustained in car accidents, falls, and other types of blunt-force trauma to the head
- Brain injuries in the area of the parietal lobe
- Brain tumors
- Epilepsy
- Alzheimer’s disease and dementia
- Hydrocephalus
- Brain aneurysms
- Shaken baby syndrome
- Multiple Sclerosis (MS)
- Lymphoma
How to Diagnose Hemianopic Patients?
There are many ways to assess a person’s visual field and determine if there are any missing areas of vision. Diagnostic tools used to identify hemianopic patients include:
- Visual acuity assessment.
- Visual field testing.
- Reading performance assessment.
Individuals found to have visual field impairments that do not originate from the eyes themselves (such as with conditions like glaucoma) should be evaluated by a neurologist to determine if there are any correlations to brain injuries. If a patient’s eyes are healthy, but they are missing a portion of their visual field, a neurological root cause is more likely.
What are the Treatments for Hemianopia?
There are several available treatment options for hemianopia depending on which type the patient has and how severe the condition is.
- Wear special glasses with prisms that help fill in visual field loss
- Use a ruler or straight edge to follow a line of text without accidentally jumping down to the next line
- Engage in neuro-ophthalmology exercises that strengthen the brain-eye connection
Interventions for hemianopia are often focused on the rehabilitation of eye movement with compensatory and restoration therapy.
Different researchers, who deal with perimetry, neurology, and psychiatry, and authors examine this field such as Pambakian, Kerkhoff, Rowe, Peli, Zihl, and Kennard alongside the studies and questionnaires that are conducted in clinical trials and vision rehabilitation.
The Trauzettel-Klosinski Lab, Institute for Ophthalmol Research is a leader in the treatment of the homonymous visual field.
Does Hemianopia Get Better?
Often, when tumors, a stroke, or another type of brain injury results in visual field loss, what has already been damaged cannot be repaired and vision cannot be recovered or restored. However, treatment interventions usually prevent new damage and new loss of vision. Preventative treatment also helps patients adapt to having low vision. Randomized controlled trials of treatment of hemianopsia after stroke with visual search training compared to Fresnel prisms actually excluded roughly half of the potential participants because their visual impairment partially or fully resolved on its own. Sufficient spontaneous recovery of the visual field occurs rarely.
Why Hemianopic Patients Have Difficulties with Reading?
- Hemianopia can lead to hemianopic dyslexia and/or hemianopic alexia due to damage to the areas of the brain responsible for processing reading text.
- The visual field defect or blind spot prevents patients from planning and executing proper reading saccades.
- Patients with hemianopia have difficulty performing reading saccades into the blind hemifield while reading horizontally.
- Hemianopic patients have difficulty seeing follow-up words in their parafoveal vision, which reduces optokinetic movement and makes reading very difficult.
What is the Difference between Central and Peripheral Vision?
Central vision is what you are able to see directly in front of you. If you move your eyes or turn your body, whatever you are looking at straight ahead of you is in your central vision. Your peripheral vision is what you see just outside of your central vision in the corners of your eyes.
