Sight and Perception in Dementia
The majority of people with a dementia are well on the way through the ageing process, and with this comes changes to sight and perception. Images become more blurred, it starts to take longer to adapt to changes in light, such as coming into a darkened room from outside. As the visual field is narrowed the vision is lost or limited in the periphery of vision, affecting a person's depth perception which makes it difficult to judge distances or see objects in 3 dimensions, what is seen now becomes flattened.
Other health conditions such as macular degeneration, complications from diabetes or a previous stroke and will also compromise an individual’s vision.
Individuals with Alzheimer’s dementia, vascular dementia and Parkinson’s disease with Lewy body dementia are more likely to have increased problems with their vision and perception.
So being aware of and taking into account visuospatial problems in our planning and development of services is vitally important, as many in our communities will be experiencing difficulties in this area.
People with dementia who have problems with their visuoperception may have difficulties with the following:
- Changes to visual field, the periphery vision when looking straight ahead become narrower, so people are unable to see things going on to the side of them.
- Changes in the ability to distinguish between contrasts in colour or figure-ground discrimination, being able to pick out an object from its background.
- Detecting movement or keeping up with fast moving pictures or events.
- Changing gaze or looking in the right direction.
- Recognising familiar faces, objects or colours.
- Depth perception – being able to recognise changes in levels or distances of objects from themselves.
- Being unable to describe what they see.
These problems can have an impact on an individual’s orientation and affect how they move around their environment. They may experience difficulties in:
- Misjudging distances and where objects are, meaning that they bump into things more regularly. In particular negotiating doorways.
- Negotiating changes in floor covering as this may be perceived as a change in level, or a shiny floor being thought of as wet.
- Judging the depth or number of stairs in particular when going downstairs.
- Misinterpreting reflections seen in a mirror or glass as a stranger or intruder.
- Mistaking people seen on television as real people in the room.
- Identifying or locating objects if the contrast with the background isn’t sufficient or the background is too busy, such as heavily patterned wallpaper with the lack of sufficient colour contrast.
There are simple environmental adaptations, you can make, to help reduce the impact of visuoperceptual difficulties.
- Use colour to highlight objects that need to be seen. For example, a coloured toilet seat, a red plate, and red handled cutlery, and coloured glasses rather than clear.
- Use colour to highlight orientation points such as doorways and camouflage to disguise doorways and switches that the individual shouldn’t use. Such as painting the door frame to the bathroom a bright yellow.
- Avoid busy patterns, changes in floor surfaces or patterns. Such as heavily patterned rugs on wooden floors.
- Replace mirrors or shiny surfaces if this is causing a problem.
- Ensure there is adequate lighting and avoid dark corners.
- Use coloured stripes or textures to define each step, use coloured handrails to hi-light the direction of slopes or staircases.
Useful tips for supporting a person with visuoperceptual problems.
- Anticipate the situation and explain the environment, walk first on to changing floor surfaces to demonstrate it is safe.
- Don’t rush the individual, allow them plenty of time, encouragement and support as they move around the environment. Slow down your own movements.
- Arrange regular eye checks and ensure glasses are clean and the correct prescription.
- Do not rearrange the furniture in a familiar environment but ensure that the area is clutter and obstacle free.
- Always introduce yourself and say who is in the room, try and stand in front of the individual rather than to one side.
- Do not draw unnecessary attention to mistakes made, avoid asking questions or insisting an object or person is named.
For more information on this subject please look at the Alzheimer’s Society factsheet here.