Vision Changes After A Stroke: New Glasses, New Me

Vision problems are common after a stroke, with around 60%-65% of stroke survivors experiencing changes to their vision or vision loss. Strokes occur when a part of the brain is starved of oxygen and nutrients, and this can affect the visual pathway. The main types of eye problems that can occur after a stroke include visual field loss, eye movement problems, and visual processing problems. While some people may regain their vision over time, others may experience long-term changes and require vision therapy or other treatments.

Eye movement problems

A stroke can cause a variety of eye movement problems, resulting from damage to the nerves that control the eyes. This can lead to both eyes not working together as a pair, causing blurred vision and double vision (diplopia).

You may experience weakness in your eye muscles, such as difficulty or inability to follow objects with your eyes (pursuit) or shift your vision quickly from object to object (saccade). This can make it challenging to focus on or track objects. Your eyes may also wobble, a condition known as nystagmus, or you may be unable to move both eyes together in a particular direction (gaze palsy).

Treatment Options

• Prisms: Prisms are effective in eliminating double vision, especially when the size of the double vision remains stable as you look around. Initially, a temporary prism may be recommended until the double vision and required prism strength stabilize. Afterward, a permanent prism can be incorporated into the glasses lens.
• Occlusion or Patching: Occluding one eye, either fully or partially, can be an effective solution for double vision. This is typically done by applying a frosting sticker to one lens of your glasses.
• Exercises: Exercises can help improve your eye movement control. For example, you can practice shifting your focus between near and far objects or perform scanning exercises by keeping your head still and moving your eyes around the room.
• Visual Scanning Training: This technique involves drawing a line down the affected side of a book with a highlighter, then practicing moving your eyes along a sentence until you reach the highlighted line.
• Limb Activation Treatment: For those with visual neglect, this treatment involves moving the affected limbs within the neglected environment. For instance, if you have left neglect, you would practice moving your left arm and leg.

When to Seek Help

It is important to have your vision checked after a stroke, even if you don't notice any symptoms. Issues with vision are common, with around 65% of stroke survivors experiencing changes to their vision or vision loss.

Visual field loss

The most common type of visual field loss is called hemianopia, where there is a loss of one half of the visual field in both eyes. This can cause difficulties with daily tasks such as reading, as words and sentences disappear when they fall within the missing visual field. It can also make it challenging to locate things, navigate traffic, or move around in crowded environments.

Another type of visual field loss is scotoma, which is a small patch of vision loss, often near the centre of the visual field. This can also impact reading and navigation.

Visual processing problems

• Difficulty recognising objects, people, colours, or text.
• Difficulty reaching for objects or seeing multiple objects simultaneously.
• Visual inattention or neglect, where individuals are unaware of things on their affected side, often caused by strokes on the right side of the brain. This can lead to bumping into objects, ignoring people, or difficulty with reading and scanning.
• Visual hallucinations, known as Charles Bonnet syndrome, where the brain generates images in the missing area of vision.
• Scanning and awareness strategies to improve visual attention and compensate for neglect.
• Using other senses, such as touch or hearing, to process information differently and improve awareness of the affected side.
• Prism lenses, which can shift images from the non-seeing to the seeing visual field, helping to reduce the risk of bumping into objects.
• Eye patches, which can be used to block one image in cases of double vision.
• Visual training and rehabilitation to improve the brain's ability to process visual information.
• Compensatory strategies, such as using glasses with prisms, to adapt to visual changes.

Other sight problems

Light Sensitivity

Light sensitivity is a common issue after a stroke. Bright lights and glare from light-coloured surfaces can bother stroke survivors. Tinted glasses or specially designed eye shields can help alleviate the discomfort. Some people find that placing a yellow transparent plastic sheet over reading material reduces glare. Brown-tinted sunglasses can also help when outdoors.

Dry Eye

Dry eye is another common issue post-stroke. It can be caused by problems with the nerves of the eyelid, the facial nerve, or the muscles of the eyelid. The rate of blinking may slow down, and the eyelids may not close completely, leading to dryness and irritation. Lubrication eye drops or ointments can help prevent more serious eye complications such as ulcers. In some cases, taping the eyelid shut at night may be recommended.

Visual Hallucinations (Charles Bonnet Syndrome)

Visual hallucinations can occur when the brain generates images in areas of vision loss. These hallucinations can range from simple patterns to complex images of people and places. They are not a symptom of a mental health problem but are caused by the brain adjusting to vision loss. While they often improve over time, they can return or worsen if the underlying condition gets worse or if the person becomes unwell. It is important to inform a healthcare professional if hallucinations occur.

Retinal Vessel Occlusion

Retinal vessel occlusion is caused by a blockage in the blood vessels supplying the retina. It shares many risk factors with stroke and can lead to tests and checks for conditions like high blood pressure, diabetes, and high cholesterol. Lifestyle changes, such as stopping smoking, maintaining a healthy weight, and eating a balanced diet, are typically advised.

Visual neglect and agnosia

Visual Neglect

Visual neglect is a common visual processing problem that can occur after a stroke, particularly when the stroke affects the right side of the brain. People with visual neglect are unaware of things on their affected side, often ignoring people or objects on that side and bumping into them. This can reduce their ability to look towards or make movements towards things in their environment. Visual neglect can range from mild to severe cases, where it may be impossible to draw someone's attention to their affected side. Treatment for visual neglect often involves learning scanning and awareness strategies to compensate for the neglect.

Visual Agnosia

Visual agnosia is an impairment in the recognition of visually presented objects, not due to a deficit in vision, language, memory, or intellect. It is often caused by damage to the anterior cortex, such as the posterior occipital and/or temporal lobes in the brain. There are two types of visual agnosia: apperceptive and associative.

Apperceptive agnosia is a failure of object recognition even when basic visual functions and other mental processes are normal. Individuals with apperceptive agnosia cannot form a whole percept of visual information and may struggle with tasks requiring copying, matching, or drawing simple figures.

Associative agnosia is an inability to identify objects despite apparent perception and knowledge of them. It involves a higher level of processing than apperceptive agnosia. Individuals with associative agnosia can copy or match simple figures but cannot name or describe common objects when tested visually. This indicates an impairment in associating the perception of objects with stored knowledge.

Visual agnosia can also manifest in several variants, including:

• Prosopagnosia (inability to recognize faces)
• Pure word blindness or agnosic alexia (inability to recognize words)
• Achromatopsia (inability to differentiate colors)
• Simultanagnosia (inability to recognize multiple objects in a scene)
• Topographagnosia (inability to process the spatial layout of an environment)
• Pure alexia (inability to read)
• Orientation agnosia (inability to judge the orientation of objects)
• Pantomime agnosia (inability to understand pantomimes or gestures)

Frequently asked questions