Vision Problems After a Stroke: Causes of Visual Field Loss and Double Vision, and How to Cope

“Since my stroke, I somehow bump into things more easily.”
“When I read a book, I lose track of where I am.”
“Things look double, and it makes me feel unwell.”

This article explains, step by step, the visual problems that can occur after a stroke: their causes, the tests that help you understand your own condition, the outlook, and the rehabilitation that can improve quality of life.

In this article, “stroke” covers both the type in which a blood vessel in the brain is blocked (cerebral infarction) and the type in which a blood vessel ruptures (cerebral hemorrhage, subarachnoid hemorrhage). Whatever the cause, damage to the brain can produce similar visual symptoms, so we use the single term “stroke.”

TOC

The cause of changes in vision is the brain

Changes in vision are caused by the brain. With appropriate measures, quality of life can be improved.

In many cases, changes in vision after a stroke are not a disease of the eye itself.
They occur because part of the brain that processes information coming from the eyes has been damaged.

Symptoms come in several types: loss of half of the visual field, double vision, and difficulty perceiving one side of space.

However, by understanding your condition accurately through appropriate tests, and by using rehabilitation and practical adjustments matched to your symptoms, you can make the most of the vision you have left and live safely and comfortably.

Why does a stroke make it hard to see?

Seeing depends on teamwork between the eyes and the brain.

If the eye is a camera lens, the brain is the computer that processes the captured image and gives it meaning. A stroke damages part of this computer, so even when the camera (the eye) is normal, things cannot be seen correctly.

Visual problems after a stroke fall into three main types.

1. Loss of part of the visual field (homonymous hemianopia)

The visual field is the area you can see while looking at a single point.
Homonymous hemianopia is a condition in which the same side (the right half or the left half) of the visual field is lost in both eyes. It is the most common visual field defect after a stroke [5].

For example, a person with right homonymous hemianopia has trouble noticing people and objects in the right half of their vision.
As a result, they may bump into obstacles on the right, or fail to notice the plate on the right side at mealtimes.

Reading can be especially difficult.
With right homonymous hemianopia, the next word cannot be seen, which makes it hard to follow a line of text.
With left homonymous hemianopia, on the other hand, it becomes hard to find the beginning of the next line [8].

This symptom occurs when blood flow is interrupted to the visual processing center at the back of the brain (the occipital lobe).

2. Double vision (diplopia)

Seeing objects double is called diplopia.
It occurs because the lines of sight of the two eyes no longer align accurately on the object being looked at.

The main cause is paralysis, due to the stroke, of the nerves that control the muscles moving the eyeball. When one eye no longer moves normally, the images from the two eyes become misaligned, and the brain cannot fuse them into a single image [4].

Diplopia seriously interferes with daily life: it makes stairs and judging distances difficult and raises the risk of falls.

3. Things are visible but hard to recognize (hemispatial neglect and visual agnosia)

This is a somewhat more complex symptom.
The condition in which attention is hard to direct to objects on one side of space, even though there is no visual field loss or abnormal eye movement, is calledhemispatial neglect.

It is often reported that, particularly after damage to the right side of the brain, attention to the left side of space is impaired.
Leaving only the left half of a meal uneaten, or not noticing when spoken to from the left, may be due to this symptom [2].

The person often does not realize it, and family members frequently notice first.

How will it change? The outlook for recovery

What most people want to know is how visual symptoms after a stroke will change over time.
The outlook differs greatly depending on the type of symptom.

Outlook for visual field loss (homonymous hemianopia)

Unfortunately, a visual field that has been lost rarely recovers on its own [7].
In particular, field loss that remains 3 to 6 months after the stroke is likely to be permanent.
For this reason, the main goal of rehabilitation is not to “restore the visual field” but to “learn how to make the best use of the remaining field.”

Outlook for double vision (diplopia)

Diplopia caused by paralysis of the nerves that move the eye is relatively likely to recover well.
In many cases the symptoms improve substantially within a few months of onset, and sometimes disappear completely [4].
Until recovery, treatment focuses on relieving the symptoms.

Outlook for hemispatial neglect

Hemispatial neglect is considered more likely to recover spontaneously than homonymous hemianopia.
One review reported recovery in about half of patients 6 months after onset [2].
The more severe the initial symptoms, the more likely some deficit is to remain, but it is a symptom that can be expected to improve with appropriate rehabilitation.

Tests done in ophthalmology and what they show

If you visit an eye clinic for visual difficulty after a stroke, we perform several specialized tests to evaluate the cause of your symptoms accurately.

Visual field test
Using a device such as the Humphrey® Field Analyzer, we draw a precise map of which areas you can see and which you cannot. This lets us objectively assess the presence and degree of homonymous hemianopia.
Eye movement test
An orthoptist checks eye movements in detail in every direction. By determining which muscles are paralyzed and to what degree, we identify the underlying cause of double vision.
Optical coherence tomography (OCT)
Optical coherence tomography (OCT) is a medical device for examining the retina in detail. By measuring the thickness of the retinal nerve fibers, it shows that when brain damage has lasted a long time, the effect reaches the retina and the nerves become thinner (retrograde degeneration). Capturing this change gives an objective clue as to how long the visual impairment has been present (old or new) [1].

The results of these tests are very important information for deciding the course of rehabilitation.

Rehabilitation and coping strategies to improve quality of life

The approach to visual impairment after a stroke centers not on “recovery,” regaining lost function, but on “compensation” and “adaptation,” living by using the function that remains.

For visual field loss (homonymous hemianopia)

Scanning training (saccade training)
This is training to move the eyes consciously and quickly toward the side that cannot be seen. Under the guidance of an orthoptist, you learn eye movements that gather information from your surroundings more efficiently. This is expected to reduce the risk of bumping into things and to improve reading speed [5].
Prism glasses
Special prism lenses are fitted to the glasses. They do not widen the visual field, but they shift the image of objects on the blind side to the edge of the visible field, prompting you to notice that “something is there.” An effect of improving safety while walking has been reported [3].

For double vision

Fresnel membrane prisms
These are sticker-like prisms attached to glasses. By bending the direction of light, they correct the misalignment between the images of the two eyes so that things look single. Even if the power changes during recovery from the nerve palsy, they can easily be replaced.
Occlusion
When prisms do not resolve the double vision, one eye is covered with an eye patch or semi-transparent tape so that you see with one eye. This removes the unpleasant sensation of seeing double.

For hemispatial neglect

Prism adaptation therapy
You wear special prism glasses that deliberately shift the visual field and repeatedly perform tasks such as reaching out and pointing at a target. This is expected to recalibrate the brain’s spatial perception and encourage attention to the neglected space [6].

Points to note in social life: driving a car

If visual impairment remains after a stroke, particular care is needed when driving.
Japan’s Road Traffic Act strictly sets the visual acuity and visual field standards required to renew or obtain an ordinary driver’s license [9].

Visual acuity of 0.7 or better with both eyes together, and 0.3 or better in each eye.
For a person whose visual acuity in one eye is below 0.3, or who is blind in one eye, the other eye must have a visual field of at least 150 degrees horizontally and visual acuity of 0.7 or better.

With complete homonymous hemianopia, the 150-degree visual field standard cannot be met, so driving is not legally permitted. This is very important for protecting not only yourself but also others.

Depending on the degree of field loss, you may meet the standard, but judging this on your own is very dangerous. Be sure to have a visual field test and have a specialist assess whether your condition meets the driving standard.

Summary

“Difficulty seeing” after a stroke affects many aspects of daily life and is a major source of anxiety for patients and their families.

However, the cause lies not in the eye itself but in the brain, and the outlook and the ways of coping differ by the type of symptom.
First, it is important to understand accurately, through specialized tests, what state your vision is in.
Then, by steadily continuing rehabilitation suited to your symptoms and practical adjustments in daily life, you can take a step toward regaining a safe and fulfilling life.

If you have any concerns about your vision, it is important to consult a specialist first and receive an appropriate evaluation.

References

Jindahra, P., Petrie, A. and Plant, G.T. (2012) ‘The time course of retrograde trans-synaptic degeneration following occipital lobe damage in humans’, Brain, 135(2), pp. 534-541. https://pubmed.ncbi.nlm.nih.gov/22300877/
Overman, M.J., Binns, E., Milosevic, E., Hollands, C., Casey, C. and Demeyere, N. (2024) ‘Recovery of Visuospatial Neglect With Standard Treatment: A Systematic Review and Meta-Analysis’, Stroke, 55(9), pp. 2325-2339. https://pubmed.ncbi.nlm.nih.gov/39016005/
Peli, E. (2000) ‘Field expansion for homonymous hemianopia by optically induced peripheral exotropia’, Optometry and Vision Science, 77(9), pp. 453-464. https://pubmed.ncbi.nlm.nih.gov/11014672/
Pollock, A., Hazelton, C., Henderson, C.A., Angilley, J., Dhillon, B., Langhorne, P., Livingstone, K., Munro, F.A., Orr, H., Rowe, F.J. and Shahani, U. (2011) ‘Interventions for disorders of eye movement in patients with stroke’, Cochrane Database of Systematic Reviews, (10), CD008389. https://pubmed.ncbi.nlm.nih.gov/21975780/
Pollock, A., Hazelton, C., Rowe, F.J., Jonuscheit, S., Kernohan, A., Angilley, J., Henderson, C.A., Langhorne, P. and Campbell, P. (2019) ‘Interventions for visual field defects in people with stroke’, Cochrane Database of Systematic Reviews, (5), CD008388. https://pubmed.ncbi.nlm.nih.gov/31120142/
Naito, Y., Koshino, Y., Ota, H., Piao, Y., Tanaka, S. and Domen, K. (2025) ‘Short-term effect of prism adaptation treatment on the severity of unilateral spatial neglect following right hemispheric stroke: A systematic review and meta-analysis’, Journal of Rehabilitation Medicine, 57, jrm42542. https://pubmed.ncbi.nlm.nih.gov/40126425/
Zhang, X., Kedar, S., Lynn, M.J., Newman, N.J. and Biousse, V. (2006) ‘Homonymous hemianopias: clinical-anatomic correlations in 904 cases’, Neurology, 66(6), pp. 906-910. https://pubmed.ncbi.nlm.nih.gov/16567710/
Schuett, S. (2009) ‘The rehabilitation of hemianopic dyslexia’, Nature Reviews Neurology, 5(8), pp. 427-437. https://pubmed.ncbi.nlm.nih.gov/19581901/
Metropolitan Police Department. Criteria for passing the aptitude test. https://www.keishicho.metro.tokyo.lg.jp/menkyo/menkyo/annai/other/tekisei03.html