Dementia is a condition that can lead to sensory changes, as well as complicate existing sensory issues. In this series of articles, we'll look at how people living with dementia might experience these changes to their senses, and how good design can enable them to better navigate their spaces. 

In our sights today is the topic of vision.

Losing vision can be frustrating and confusing for anyone, at any age, but there are particular difficulties for those living with dementia.

Dementia can not only complicate issues to do with loss of sight – it can cause them as well.

Vision problems in dementia are sometimes referred to as ‘brain blindness'. This is where an optician or ophthalmologist confirms that there are no problems with the eye, but the person still cannot see properly. In this case, the issue is not with vision but with the person's perception or understanding of what they are seeing.

How do you know something is wrong?

Sight loss is often under-diagnosed in people with dementia because one condition can be mistaken for another, or carers aren't aware that the problem exists.

Some signs to look out for among those living with dementia are:

• A narrowing visual field, meaning they don't notice things in the periphery of their vision
• Holding things up close
• Becoming withdrawn or uncommunicative
• Being clumsy or falling more
• Having visual hallucinations
• Feeling confused and disorientated
• Being startled by noises or people approaching

How does dementia affect vision and perception?

There are a number of ways in which dementia may cause changes to vision or perception, which can be distressing and stressful.

• Misperception, e.g. a black mat on the floor which the brain ‘sees' as a black hole, or blue flooring in the bathroom which the brain ‘sees' as water.
• Misidentification, e.g. mistaking an object for something else and finding it alarming, such as thinking a coat stand in your hall is a person and being concerned there is a stranger in your home.
• Posterior cortical atrophy (the loss of brain cells in the region responsible for visual processing and spatial reasoning), leading to:
  – Difficulty recognising familiar objects and faces
  – Increased sensitivity to bright lights or shiny surfaces
  – Double vision and difficulty seeing in fading or low light conditions
  – Difficulty judging distance, speed and perspective—this can cause problems with stairs, the speed of traffic, reaching out for things or putting things down on surfaces
  – Stationary objects may appear to move
• In vascular dementia other complications can occur, e.g. hemianopia where the peripheral visual field is reduced by half, and on a particular side.
• Visual hallucinations, e.g. seeing flashing lights or animals/people.

How can good design help?

At The Dementia Centre, we recommend several helpful adaptations that make a real difference to the wellbeing of people living with dementia.

• Double the usual levels of light. Maximise the use of natural light since it is usually much brighter. We need a higher lux level as we age, so remember to light the space for the people living in it, not those working in it.
• Ensure good contrast. If something does not contrast sufficiently, then it may be less visible. This can have severe consequences - a person may miss a chair or the toilet seat when sitting down. An easy solution is to have a dark seat on a white toilet base so the contrast is clear.
• Do not rely on colour for orientation. If an older person's ability to see colour is impaired, and their memory is too, it is not reasonable to expect them to be able to find their way using colour cues.
• Ensure the floor is the same tone throughout. Avoid speckled, sparkly or elaborately patterned flooring as this may be seen as litter or dirt, or as if it is moving.
• Avoid patterns. Swirls, vertical strips and complicated patterns in fabrics can be confusing. Choose plain fabrics in solid colours.

These may seem like subtle nuances, but for people living with dementia they can mean the difference between confusion and stress, and confidence in their ability to navigate their world.

Better design choices really can lead to better lives.