Learn more about visual field loss, eye movement problems and visual processing problems and how they’re treated. 

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What are the main types of vision problems? 

Visual field loss 

Your visual field is everything you can see – including straight ahead (central vision) and out to the side (peripheral vision).  

Visual field loss means you are unable to see a section of your field of vision, usually because the vision areas of your brain have been damaged by the stroke. The eyes themselves work normally, but the brain cannot process the images from one area of vision.  

It almost always affects the same side of the visual field in both eyes (this is called ‘homonymous’ visual field loss). The part of the visual field that is lost and how big it is depends on where the stroke occurred in your brain. 

Types of visual field loss 

  • Hemianopia means losing the left or right half of the visual field of both eyes. It’s sometimes called homonymous hemianopia. 
  • Quadrantanopia also will affect the left or right field of both eyes, but only one-quarter is lost. 
  • Scotoma is a small patch of vision loss, often near the centre of vision. It’s a less common type of visual field loss. 

Often people think the vision in one eye has been affected, but it is usually one side of the visual field of both eyes. 

How do I know if I have visual field loss? 

Some people with visual field loss may not be aware of the missing area of vision. You may become aware of it because of how it affects your everyday life. Hemianopia can make reading difficult because it’s hard to find the beginning or end of a line, or find the next line. You might only notice the field loss if you look in a mirror and can only see one side of your face, or if you can only see part of your TV or phone screen. It can be difficult to get around in unfamiliar or crowded places, as you may miss obstacles on the side of field loss. 

Treatment and support for visual field loss 

Visual field loss can improve and some people make a complete recovery.  Many people will have a permanent visual field loss, but there are techniques to help you make the most of your remaining vision.  

An eye or rehabilitation specialist can assess your eye problems and advise you on what will work best for you. 

Visual scanning training 

This encourages you to look to your left and right sides in a more efficient way. This is often how occupational therapists will teach you to cope with your field loss, and they can help you practise this in everyday tasks. There are also some free online therapies, such as EyeSearch and ReadRight, which are designed to improve the speed and accuracy of eye scanning and reading.  

Optical aids and other tools 

You may be given a plastic prism to wear in your glasses, to help you see a little further to one side. Some vision on the ‘good’ side is sacrificed, and not everyone can use them as some people find it gives them double vision, confusion or headaches. 

If you find reading difficult, using line guides, having good lighting and using edge markers on books and newspapers may be helpful.  

Eye movement problems 

A stroke can lead to a variety of problems with control of the muscles that move your eyes. These include: 

Impaired eye movements - these may mean that one eye, or both of your eyes, do not move correctly. It can affect your eyes’ ability to move between objects, or to follow a moving object, like someone walking past. If you’re unable to move both eyes together, it may give you blurred vision or double vision (diplopia.) 

Eye movement problems can make reading more difficult and can also affect your general mobility. For example, if you’re unable to look around quickly, walking outside may be more challenging.  

Eyes move constantly, or wobble - this can make it hard to focus on objects and cause moving images and double vision. This condition is called nystagmus. 

Impaired depth perception and difficulty locating objects - for example, when making a cup of tea, you may misjudge the position of the cup and pour water over the edge, rather than into the cup.  

Treatment for eye movement problems - there are a number of treatment options. Exercises can help if you have difficulty moving your eyes inwards, such as when you read. Prisms can improve double vision. A patch over one eye can also be used to avoid double vision. This makes it easier to see, but using only one eye (monocular vision) can also cause some difficulty. You can work with an orthoptist to find out which option works best for you. 

Visual processing problems 

Some vision problems after stroke are due to the brain having difficulty making sense of the information received from the eyes. This can happen in many ways, for example, difficulty recognising objects or people by sight, or recognising colours. It can cause difficulty when you try to reach for objects, or make it harder to see more than one object at the same time.  

Visual inattention (also known as visual neglect) 

The most common type of visual processing problem is visual inattention or neglect. This means you are unaware of things to one side of you. It’s often due to strokes on the right side of the brain, so the left side of visual space is affected. For example, you may be unaware of objects and people on your affected side. You may ignore people or bump into things because you do not realise they are there.  

Visual inattention can also reduce your ability to look or make movements towards part of your environment. It can be mild or more severe. When neglect is severe, it may be impossible to draw someone’s attention round to their affected side.  

Visual field loss and neglect can happen together, which can make it harder to use strategies like visual scanning or patches.  

Treatment for visual processing problems 

Many people recover well from visual inattention. Your occupational therapist should work with you to help you cope with inattention. There is a range of rehabilitation, and you might learn to scan to the affected side (like for visual field loss) and ways to make you more aware of one side, such as asking family and friend to approach from that side. 

If you have problems such as difficulty recognising colours, faces, objects, complex scenes or text, you may be taught to use your other senses (for example, touch or hearing) to process the information in a different way and to help you to improve your awareness of the affected side. 

Other sight problems 

Dry eyes 

If you have weakness in your facial muscles and eyelid muscles, you may have difficulty closing the eyelids fully, or your eyes could stay open when you are asleep. This can lead to a dry eye and irritation. It’s important this is treated early with lubrication drops or ointment to prevent more serious eye complications such as ulcers. You might be advised to tape the lid closed at night if the eye does not always close fully. 

Light sensitivity 

Light sensitivity is common after a stroke. It’s sometimes called photophobia. You might be bothered by bright light, or glare from light coloured surfaces. Some people find that a yellow or orange tinted overlay or wearing tinted sunglasses helps reduce glare. 

Visual hallucinations (Charles Bonnet syndrome) 

Visual hallucinations happen when the brain generates images in the missing area of vision. The images most often appear in your blind area. You might see simple patterns, or more complex images of people and places. For some people, it’s the only time they notice the area of vision loss. It is also known as Charles Bonnet syndrome.   

Visual hallucinations caused by sight loss are not a symptom of a mental health problem. They often start after a sudden loss of vision. They almost always improve with time as your brain gets used to the loss of vision. They can return or get worse if your sight gets worse, or if you are unwell due to an infection.  

Hallucinations can be caused by other conditions affecting the brain, so if you start having them tell your GP, eye health specialist or specialist stroke nurse.  

There is no medication or treatment for visual hallucinations, but there are organisations that support people with hallucinations. RNIB publishes a guide to Charles Bonnet syndrome, and Esme’s Umbrella is a campaign group raising awareness of the condition.  

Retinal vessel occlusion  

Retinal vessel occlusion is due to a blockage in one of the blood vessels to the retina (retinal arteries). This is called a retinal vessel occlusion. It is also called an ‘eye stroke’ but unlike a stroke, it does not affect the brain. It affects one eye, rather than both eyes which are affected in hemianopia. All vision in one eye can be lost, or just the top or bottom half of vision.  

Retinal vessel occlusion shares many of the risk factors for stroke, so you will be given tests and checks for conditions like high blood pressure, diabetes and high cholesterol. You should be advised on taking steps to improve your health such as stopping smoking, maintaining a healthy weight and eating a balanced diet.