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Each of our senses has an important part to play in our relationship with the world and how we experience life. So what happens when dementia begins to affect these senses?
In this blog we explore sensory changes to vision which you might experience as someone living with dementia and some ways that your support network can help make life easier to navigate.
It’s important to stress that this won’t be a part of every dementia journey but being prepared for what may come is the best step towards continuing to live well alongside a diagnosis of dementia.
Sight Changes for a Person Living with Dementia
Like hearing loss, changes to sight can be age related, but for someone living with dementia this can be more challenging. Regular eye checks and reviews are important and if required then corrective glasses should always be worn.
Often sight impairments are missed when symptoms are mistaken for dementia related symptoms. Alternatively, a person may have good eye health but still experience visual changes which are caused by dementia. This might be due to misperception, if the brain is no longer correctly interpreting what is seen.
Visual processing is complex; the brain has to work very hard to process images captured by the eye and then relies heavily on memory to interpret and add meaning to the images. Visual changes can also be due to hallucinations which occur when a person is seeing something that only exists within their mind.
Differences Between Changes to Vision for People Living with Dementia and Normal Age-Related Changes to Vision.
Normal age-related vision changes can include a reduction in the sharpness of images seen, colours becoming dulled, a reduction in the size of the visual field, loss of peripheral vision, requiring increased contrast and light to see clearly, increased glare sensitivity, difficulties with depth perception.
Additionally, there is increased risk of developing sight related conditions such as cataracts, glaucoma and macular degeneration.
Normal age-related sight loss may be more confusing & disturbing for a person with dementia than someone who can understand the cause of their visual loss. Vision changes which are linked to dementia can include the following:
Visuo-perception difficulties
This is often confused with hallucinations but a person may find their brain is misinterpreting an object. This could be misidentification, when the brain is unable to identify a specific object for example a dressing gown hanging on a peg could be misidentified as person. Or it could be misperception, this is when something is seen but the brain cannot make sense of what it is e.g. a black door mat may appear as a black hole or blue flooring is misperceived as water. Shadows and reflections including mirrors can also be very disorientating for a person living with dementia and can increase cognitive symptoms.
Hallucinations
When someone sees, hears or smells, tastes or feels something that only exists in their mind. They can be complex and can vary greatly. Some people may not be affected by non-threatening hallucinations, but others can be frightening and can increase anxiety and agitation.
Families and carers are important in these situations to calm and reassure the person. Rather than dismiss the hallucination, ask them about what they are seeing. If they are disturbed by it, sometimes it can help to change environments and start a different activity. If they are becoming problematic it is important to consult with the GP to check if they are a side-effect of a current medication or if a medication change might help. It is worth keeping a note of when they occur, if there are any particular triggers you notice, what they see and how long they last for.
Posterior Cortical Atrophy (PCA)
This is a rare type of dementia affecting visual processing. It causes changes to the posterior cerebral cortex in the brain which is responsible for vision and results in a progressive decline in the person’s ability to process visual information.
Managing visual disturbances
Vision related difficulties that develop due to dementia can affect people differently but some of the signs to look for are if the person:
Becomes withdrawn or incommunicative
Becomes more clumsy
Starts to fall more frequently
Shows increased disorientation
Appears to be startled by noise or people approaching (perhaps due to loss of peripheral vision)
How to help manage visual changes
Consider the person’s environment and ask yourself, are there any adaptations which could make it safer and easier for them to navigate.
Pay particular attention to bright colour and contrast, this is especially useful to differentiate objects and furniture. For example, a wooden chair on a similar wooden floor may be missed, a blue towel against blue tiles may not be used or a white sandwich on a white plate may not be eaten as the person cannot see these things.
Avoid patterns that could be misinterpreted, for example stripes and swirls can sometimes appear to be moving and dots or sparkles may be interpreted as dirt or insects.
Approach people from the front so they have a clear view and plenty of time to process who is approaching them (particularly if struggling with peripheral vision).
Allow people longer to process what they see, if helpful give them a simple verbal description.
The eye needs to receive light to operate the body’s natural circadian rhythm (body clock). Ensure there is plenty of natural light in the home during the day to support this and then use soft lamps in the evening but try to avoid shadows.
Check that any prescription glasses are frequently cleaned and the person is encouraged to wear them. If the person has both distance and reading glasses have different colour glasses and matching cases that are labelled so it is easier for them to identify the ones they need.
It is important to have regular assessments with an optician to check for any sight loss that could be improved with glasses. It is possible to have vision tests at home if this is easier, so speak to a Wayfinder who can support you to find a local service. If you are placed on a sight impairment register then the Royal National Institute for the Blind (RNIB) has sight loss advisors who can provide further support for you.
For more information on vision changes for a person living with dementia, or any other dementia-related queries or support, call our Wayfinding team on 01243 888691, or email info@dementiasupport.org.uk
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