What to know about vision problems after stroke

Vision problems may occur after a stroke due to damage in a certain part of the brain. Brain cells die quickly without oxygen, and a loss of blood supply to the brain starves these cells of oxygen.

If a stroke affects the part of the brain that controls and receives information from the eyes, this can cause vision problems.

For instance, a stroke can damage the occipital lobe, which is responsible for processing visual inputs. A stroke can also affect the brainstem, which handles visual balance, interpreting objects, and eye movements.

Vision problems that a person had before a stroke may also worsen after a stroke or add to any new visual impairment that it causes.

Vision problems are very common after a stroke. According to research from 2019, about 60% of people who survive a stroke have a visual impairment to some degree. However, the percentage of people who experience symptoms varies widely among the types of impairment.

In some cases, vision changes may be temporary or improve with training. However, other vision changes may be permanent.

A person may experience various types of vision problems after a stroke.

Visual field loss

The visual field is everything a person can see when they focus their eyes on a particular point. It will include any direct objects straight ahead, as well as everything around them and to the sides. If a person experiences visual field loss, they will lose the ability to see part of this field of vision.

The type of field loss will depend on the area of the brain that the stroke affected.

Visual field loss may occur on one side in each eye so that, for example, a person can only see on the left or right side. This type — the most common following a stroke — is called hemianopia, and training may be necessary to help the person cope with the changes to their field of view.

Sometimes, visual field loss may cause a blind spot or scotoma that affects one or both eyes. This issue may also occur in the center of the visual field. In these cases, looking at an object may make it “disappear” from the field of view.

In some people, visual field loss may occur at the top or bottom of the eye, resulting in the loss of the upper or lower area of the field of vision. Alternatively, it might affect peripheral vision, which is the part of the visual field near the edges of the eyes.

Other cases may affect a visual field quadrant, resulting in the loss of one-quarter of the visual field.

Visual neglect

A stroke can also affect how the brain processes visual information. This impairment can cause several visual processing problems. The most common type of problem is visual neglect.

Visual neglect or spatial inattention occurs when a person does not respond to visual stimuli in the areas that the stroke affected. They may not be aware of or respond to things on the affected side.

Visual neglect may occur on its own or along with other issues such as visual field loss. Having both may make treatment difficult or make some training techniques less effective.

Agnosia

Agnosia is a rare neurological disorder that occurs due to a stroke. People will be unable to retrieve information associated with visual memory from damaged areas of the brain.

As a result, a person may have trouble recognizing familiar sights in their visual field. These include common objects, familiar faces, and everyday sights that may not make sense.

Eye movement issues

Depending on the area of the brain that the stroke affects, a person may also experience issues with physical eye movements. If a stroke affects the nerve control of the eye muscles, a person may have difficulty controlling the movement of the eye or the visual field itself.

Some may experience nystagmus, a constant movement of the eyes. The movement may be unsteady or jittery, and the eyes may move back and forth along one axis or in a circle. Others may experience too much movement in the eye, such as rapid eye jiggling or turning.

A person may have difficulty moving their eyes in a certain direction or controlling them while tracking an object in their visual field. The eyes may jump or flick when the person gazes at an object.

Eye movement issues may also affect the way a person judges the distance between objects.

Blurred vision

Damage that affects nerve control may also cause blurred vision or double vision (diplopia).

Blurred vision may go away with rehabilitation and training in some cases, but in others, the symptoms may persist.

Other issues

Other visual problems may occur after a stroke.

For example, some people may have issues with light sensitivity. Others may have problems blinking or fully closing their eyes, which may also lead to other symptoms, such as burning or irritation from very dry eyes.

Issues such as loss of balance and coordination or changes in depth perception may also occur. It can be harder to maintain balance if a person cannot see clearly, and they may bump into things or stumble as a result.

Certain problems with the vision may go unnoticed or undiagnosed or be easier to ignore than others. However, getting a diagnosis from an eye specialist is important in determining the best treatment.

After a stroke, a person should work closely with their healthcare team to discuss any possible visual symptoms.

A doctor may refer them to a specialist even if they do not have noticeable symptoms.

Doctors specializing in eye and brain issues include neuro-optometrists and neuro-ophthalmologists. These professionals diagnose and treat neurological conditions that affect the visual system and conditions affecting the nerve pathways that connect the eyes to the brain, respectively.

A specialist can help put together a treatment plan for vision problems, with the aim of improving vision where possible.

Training

Some training techniques may help the eyes adjust to blind spots or areas of vision loss.

For example, scanning is the process of training the eyes to navigate around the areas of vision loss. It encourages people to look to their left and right sides in a systematic way. This approach helps an individual make the most of their remaining vision.

Eye doctors may also use audio and visual stimuli combinations during training to help retrain the eyes to compensate for visual field loss or loss of depth perception.

Balance training or spatial awareness training may help with loss of coordination or equilibrium.

Early and frequent training can cause some recovery in the first few months after a stroke. However, research from 2019 notes that many visual defects become permanent in a high percentage of patients.

Corrective lenses

Glasses and corrective contact lenses generally do not help with vision loss from a stroke.

However, some special types of corrective lenses may help with specific issues. For example, a person can use a prism on one or both lenses of their glasses.

Prisms shift the direction of light coming into the eye to help change how a person perceives objects. They may help move objects into the person’s field of view or prevent the individual from looking into an area of vision loss.

Doctors may offer other at-home instructions to care for the eyes and vision issues.

Depending on the underlying vision issue and how it affects a person, doctors may give the person special instructions, such as:

• avoiding driving at night or in low light situations
• using over-the-counter eye drops to prevent dryness
• wearing sunglasses or anti-glare glasses to reduce light sensitivity
• using in-home training aids or equipment to continue training, including low vision aids such as magnifiers
• making changes around the home to prevent falls, such as installing guard rails and safety lights
• using rulers and markers when reading to highlight the beginning and end of sentences and maintain a position along a line of text

Vision problems after a stroke are common. The type of issue that a person experiences can vary widely depending on the area of the brain that the stroke affects.

With early training, some people may experience improved vision and train their eyes to overcome losses in vision. However, some vision changes are permanent.

Working with a specialist early on is important to help give a person the best chance to cope with visual impairment and make improvements where possible.