Hemianopsia is the loss of half of the visual field. A person with hemianopsia only sees a portion of the visual field from each eye. It is classified by where the missing visual field is located:
- Outer half of each visual field (bitemporal)
- The same half of each visual field (homonymous)
- Right half of each visual field (right homonymous)
- Left half of each visual field (left homonymous)
- Upper half of each visual field (superior)
- Lower half of each visual field (inferior)
Hemianopsia is caused by health problems that affect the brain or optic nerves. Common ones are:
Less common causes are:
- Exposure to toxins
- Neurodegenerative disorders
- Nonketotic hyperglycemia
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The risk of this problem is higher in people who have a condition that affects the brain. A problem with the optic nerve may also raise the risk, but this is not as common.
Vision loss can be mild to severe. Problems may be:
- Bumping into objects
- Problems reading
- Problems driving, such as changing lanes when there is an oncoming car or sideswiping objects
- Seeing lights or shapes that are not there
You will be asked about your symptoms and health history. A physical exam will be done. You may need to see a doctor who treats the eyes or one who treats problems of the brain.
Your field of vision will be tested. This can be done with a visual field test that makes a map of your field of vision.
Images may be taken of structures inside the brain. This can be done with an MRI scan.
Any underlying causes will need to be treated. This may improve vision in some people.
For others, the goal of treatment will be to manage vision loss. Choices are:
- Visual aids, such as mirrors, telescopes, and prisms that are attached to eyeglasses
- Reading strategies, such as using a ruler to mark the start and end of text
- Lifestyle changes, such as turning the head and eyes to view things outside of one's field of vision
The risk of this problem may be lowered by managing health problems that could lead to a stroke.
American Academy of Ophthalmology http://www.aao.org
Lighthouse Guild http://www.lighthouseguild.org
Canadian Ophthalmological Society http://www.eyesite.ca
Canadian Stroke Network http://www.canadianstrokenetwork.ca
Brain abscess. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/brain-abscess. Accessed January 12, 2021.
Homonymous hemianopia. North American Neuro-Ophthalmology Society website. Available at: http://www.nanosweb.org/files/public/Homonymous%5Fhemianopia.pdf. Accessed January 12, 2021.
Muccio CF, Caranci F, et al. Magnetic resonance features of pyogenic brain abscesses and differential diagnosis using morphological and functional imaging studies: a pictorial essay. J Neuroradiol. 2014 Jul;41(3):153-167.
Visual field loss in children. Perkins School for the Blind website. Available at: http://www.perkins.org/assets/downloads/low-vision-clinic/handout-visual-field-loss-child-rev1-31-11.pdf. Accessed January 12, 2021.
- Reviewer: EBSCO Medical Review Board Rimas Lukas, MD
- Review Date: 12/2020
- Update Date: 01/12/2021