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Around 1 in 3 of patients with a brain tumour report a problem with their vision as a result of the tumour or its treatments.
It's important to remember that not everybody who is affected by a brain tumour will experience sight difficulties or visual impairment.
For those that do, the symptoms and severity will differ from person to person, so you may not have the same problems as someone with a similar diagnosis and treatment plan.
The visual field is the total area you can see while looking at one point. There are many different types of field loss. If the outer part of your visual field is damaged, it's called peripheral field loss.
Other types of field loss can be more obvious. You may have a quarter of your visual field affected (which is called a quadrantanopia) or half of your field affected (which is called a hemianopia). If you've lost half your field of vision on the same side in both eyes, it's called a homonymous hemianopia.
Everyday tasks, such as reading, watching television and travelling safely outdoors in new areas, can become difficult. You may often feel surprised by items or people suddenly appearing or be unaware of the field defect and unconsciously neglect the missing area of vision. This can lead to bumping into things on one side, eating half a plate of food only, or only reading half a line of print.
Double vision (also known as diplopia) is when you see two images of a single object. The images may be side by side, one on top of the other, or diagonal to each other. It may happen all the time, or only in certain circumstances.
Double vision may be very obvious, or may appear as blurred vision. Young children may not be able to say that they have double vision. Instead, they may cover one eye, screw their eyes up, turn their head sideways or tilt it instead of looking straight. You may also notice one eye turning in or out which could cause double vision.
Your vision may become sensitive to light due to the treatment for your tumour, this is also known as photophobia. This could be short term or long term.
Light sensitivity is when your brain struggles to adjust to different levels of light. You may need to allow extra time for your eyes to adjust when moving between areas of different levels of light. This may be very uncomfortable.
Some large tumours can cause facial palsy. This can lead to dry eyes or watery eyes, difficulty closing your eyes, redness, and blurring of vision.
If you cannot close your eyes, the tears in your eyes can't be spread over the eye and the surface of the eye can be exposed for long periods of time. This can cause dry, irritated eyes and increase the risk of infection.
Your bottom lid may also turn outwards (ectropion), which means the tears don't drain properly. This can lead to watery eyes and blurry vision.
Abnormal eye movements can come in many forms. Both your eyes may not work together to look at the same point (squint), or your eyes may wobble out of control (nystagmus). Both of these will make it harder to focus, and can cause blurry or double vision.
Use BRIAN’s quality-of-life tracker to monitor any new or changing vision problems. You can use the results to ask for a specialist appointment to help give you the skills and equipment you need to adapt to your sight problem and keep up with hobbies and everyday tasks.
BRIAN is our trusted online app where you can track your experience, compare it with others who’ve been there and get the knowledge you need to make informed decisions.
Position of the tumour
Several areas of the brain are involved in helping you see. So, the symptoms you experience can vary depending on the location of the tumour.
Swelling of the optic disc
Increased pressure in the skull can lead to the optic disc at the back of your eye becoming swollen and causing sight difficulties.
This can be caused by a number of conditions, but when it is due to raised intracranial pressure (ICP) it is known as papilloedema.
Papilloedema can be diagnosed by opticians during normal eye examinations. This can be important as people don't usually experience visual symptoms in the early stages of papilloedema.
Pressure on the optic nerve
A growing tumour or build-up of cerebrospinal fluid (CSF) in the brain can squeeze healthy brain tissue, including the main cranial nerves within the brain.
The resulting pressure can alter how well the nerves work, and if this happens to the optic nerve, your vision can be affected.
Effect of treatment
If radiotherapy is delivered near to your eyes, there's a chance of developing a cataract in the lens of the eye several months or even years later.
Cataracts can make your vision cloudy, blurred or dim. However, they can usually be easily treated with a simple, small operation.
Long-term use of use steroids can lead to increased pressure in the eyes (known as ocular hypertension). This can damage parts of the eye that are vital for vision and can lead to glaucoma if it isn't treated.
Glaucoma is a gradual, but permanent, loss of vision beginning at the outer field of vision (peripheral vision). So, it's important to go to the opticians regularly, to monitor for any signs of these side-effects.
Increased eye infections and delayed healing of the surface of the eye are also common side-effects of steroids that can lead to sight difficulties.
If you have a problem with your vision because of your brain tumour or as a side effect of your treatment, you can ask to be referred to an eye expert (ophthalmologist). They'll check the health of your eyes and provide tools and advice to help you carry on with your daily activities. They can also refer you to other eye specialists if needed.
Many people who experience sight difficulties live very independent lives. No matter what level of visual impairment you're living with, there are lots of strategies to support you in being as independent as possible.
Your employer, by law, needs to make basic changes to accommodate your vision problem, such as changing your equipment and allowing you to return to work in stages, including flexible hours or part-time working.
If you're currently trying to find a job, all employers need to make sure that any vacancies don't exclude people with a disabilities from applying for a job.
And, if employers reject an application from a person with a disability, it must be based on their performance at interview rather than having to make reasonable adjustments to help the applicant at work.
The Government's Access to Work scheme can help you identify reasonable adjustments that can be made to help you find or stay in employment, provide training and potentially fund any equipment you require.
If your child is struggling at school, The Partially Sighted Society design and print bold lined stationery and other specialist equipment for students with a vision problem. A free child-centred V.I. Assessments are available by request at partsight.org.uk.
Disabled Students' Allowances (DSAs) is a scheme which should assess your needs and provide suitable equipment and training to help you begin or continue your education. Your university or college will have a disability advisor who could signpost you to accessing help and support.
If you're looking to attend a university, some useful questions to ask could be:
There are various schools and colleges specifically designed for those who are sight impaired or severely sight impaired:
If you've been diagnosed with a brain tumour, the law states that you need to tell the DVLA or the DVA as soon as possible.
Your general practitioner (GP), neurologist (brain specialist) or ophthalmologist (eye specialist) will check the impact of the brain tumour and should be able to confirm if you can still drive.
Although sight difficulties can make it harder to read, other symptoms cause by a brain tumour could also be the issue.
Aphasia is where the brain cannot process words in the correct way. It affects speaking, reading and writing. You may be able to see the words correctly, but make mistakes when saying them out loud or might not be able to understand them.
Sometimes, this can be mistaken for poor vision and you may be referred to a low vision clinic. They will check your eyes and see if your problems are due to your ability to recognise and process what you're looking at.
If the low vision advisor finds that your problems are due to language and literacy, they will refer you to your GP to see a Speech and Language Therapist.
If you have further questions, need to clarify any of the information on this page, or want to find out more about research and clinical trials, please contact our team:
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