Specialty Vision · Vision Simulator
Neuro & visual field
When the optic nerve or the brain's visual pathways are damaged — often by a stroke, tumour or injury — part of the visual field goes missing in a set pattern, such as the same half of vision in both eyes (homonymous hemianopia).
When half (or a quarter) of the view is missing
Damage along the visual pathway — for example after a stroke — can remove the same side of vision in both eyes. People often bump into things or miss text on one side. Pick a pattern below.
Overview
Vision doesn't depend only on the eyes — the signal travels along the optic nerves and through the brain. Damage along this pathway removes a matching section of the visual field rather than blurring everything, and where the damage sits decides the pattern. A stroke at the back of the brain commonly causes homonymous hemianopia (the same left or right half missing in both eyes); a pituitary tumour can cause loss of both outer halves (bitemporal hemianopia); other injuries cause quadrant or altitudinal defects. Because the eyes themselves look normal, these losses are often discovered only on a visual field test — or after bumping into things and missing words while reading.
Symptoms of visual field loss
- Missing or dim vision on one side, or in one quadrant, in both eyes
- Bumping into people or objects, or missing steps, on the affected side
- Losing your place or skipping words when reading
- Trouble with driving, navigation and judging where things are
- Often no awareness of the gap, because the brain 'fills in' the missing area
What causes visual field loss
- Stroke affecting the brain's visual pathways — the most common cause of homonymous hemianopia
- Brain tumours, including pituitary tumours pressing on the optic chiasm
- Head injury or brain surgery
- Optic-nerve disease, multiple sclerosis or other neurological conditions
Visual field loss risk factors
- High blood pressure, diabetes, high cholesterol and smoking (stroke risk)
- Older age and irregular heart rhythm (atrial fibrillation)
- Previous stroke, head injury or brain tumour
Prevention & early detection
- Field loss itself isn't 'preventable', but you can lower the risk of its commonest cause — stroke — by managing blood pressure, blood sugar and cholesterol, not smoking, and staying active
- Seek emergency care immediately for stroke warning signs; fast treatment can limit the damage
Treatment
The underlying cause — such as a stroke or tumour — is treated first. The field loss itself may partly recover in the early weeks, but established defects are usually permanent. Vision rehabilitation helps people adapt: scanning training teaches systematic eye movements into the blind side, reading strategies help with text, and prism glasses can shift part of the missing field into view. Occupational therapy and low-vision services support safe daily living and clarify driving eligibility.
When to see an eye doctor
Sudden loss of part of your vision — especially the same side in both eyes — can be a sign of a stroke and is a medical emergency: call emergency services immediately, because urgent treatment can save brain tissue and vision. Any new, unexplained visual field loss should be evaluated promptly to find and treat the cause.
Seek urgent care for:
- Sudden loss of half or part of your vision
- Vision loss with weakness, numbness, slurred speech or a severe headache
- A shadow or 'curtain' across part of your sight
Frequently asked questions
Why do both eyes lose the same side?
Because the loss happens in the brain or optic pathway, not the eye. After the signals from both eyes are combined and sorted, damage on one side of the brain removes the matching half of the field from both eyes — that's homonymous hemianopia, most often caused by a stroke.
Will visual field loss come back?
Some recovery can happen in the first weeks after a stroke or injury, but field loss that remains after that is usually permanent. Rehabilitation — scanning training, reading strategies and sometimes prisms — helps people use their remaining vision more effectively.
Can I still drive with hemianopia?
It depends on the extent of the loss and your local laws; many people with significant hemianopia cannot drive safely or legally. An eye doctor and a formal visual field test determine eligibility, and low-vision specialists can advise on options.
Why didn't I notice the missing area?
The brain tends to 'fill in' missing regions, so many people don't perceive a black gap — they just bump into things or miss words on one side. That's why field loss is often found only on a visual field test.
Sources
- Homonymous Hemianopsia — Cleveland Clinic
- Visual Rehabilitation Strategies for Homonymous Hemianopia — American Academy of Ophthalmology