Age is a risk factor for developing both dementia and sight loss. It is therefore not surprising that many people living with dementia also have difficulty seeing. The onset of both these conditions can make living with dementia even harder. Another layer of complexity is the fact that sight loss often goes undiagnosed in people living with dementia. The symptoms of dementia tend to either mask sight loss or be mistaken for it. However, if we can identify visual impairments, understand why it’s happening, and introduce appropriate interventions, we move towards a better quality of life.
How does vision work?
Visual functioning, which is our ability to see our surroundings, process it and react to it, depends on our eyesight and brain health. Vision starts with light passing through our eyes. This information is then sent to parts of the brain responsible for processing what we see. This includes processing colour, contrast, spatial awareness and depth perception. Basically, it helps us understand how far an object is from us, its dimensions, depth, colour, and sharpness amongst other things.
As we age, develop eye conditions, and/or dementia, our visual system is affected. The aspects of visual functioning that can be affected include:
- Field of vision – As we age our visual field, which is essentially the area of space that we can see without moving our head or eyes, decreases. This includes loss of peripheral vision. The field of vision is even smaller when dementia comes into the picture. It’s like going from being able to see the entire living room without moving to just seeing the window in the middle.
- Depth perception – Taking in the visual field and processing it becomes harder over time, especially at the later stages of dementia. The brain eventually can only take in information from your surroundings from one eye, thereby losing depth perception. This means it becomes difficult to figure out if what you see is 3-dimensional or 2-dimensional. It makes judging the level and depth of stairs and ramps difficult.
- Coloured perception – Detecting differences in colour becomes more difficult, specifically pastel and dark colours. This means that someone with dementia may start to struggle to identify and distinguish items of the same colour, like for example a plate from the table.
- Blurring – Reduced visual acuity making finer details more difficult to see and images close up more blurred.
- Reaction time – The pupil is slower in reacting to bright light along with speed of processing information by the brain slows down
As a result of the above changes in eyesight and/or brain health, a person’s interaction with their surroundings changes. You will see changes in how they perform daily tasks, the decisions they make, and/or changes in their behaviour.
How do you identify sight loss?
The first step is to identify sight loss as early as possible. Here are a few things that might indicate a person living with dementia is experiencing sight loss:
- Holding the book closer to them or magnifying text while reading
- Difficulty recognising familiar faces
- Struggling to cope with going from a dark room to a bright place and vice versa
- Spending a lot of time looking for things
- Tripping, stumbling or walking into things more frequently
- Difficulty with finding food on their plate
- Avoiding or ignoring piling unwashed dishes or unopened mail
- Less comfortable and confident about going out on their own with difficult crossing a road or unable to find and read signage
- Struggling to see well with their current glasses
- Misinterpreting a shiny floor for water or getting anxious near a patterned flooring
You might also notice behavioural changes as a reaction to sight loss, which could include:
- Becoming withdrawn, reserved and quiet
- Having visual hallucinations (seeing things that aren’t there)
- Feeling confused and disorientated
- Frequently startled by noises or people approaching
While many of these indicators can be problems with eyesight and/or the result of dementia, it is important to get a formal diagnosis by an optician. Understanding if it’s an eye condition, which you can read about in our article on Causes of sight loss in dementia, or dementia is key to implementing the right care strategy.
What is the impact of sight loss?
Sight loss affects more than one’s ability to see the world clearly. The consequences of sight loss often negatively impacts quality of life, including the number of physical and mental health issues. When a person with dementia starts to lose their vision, many aspects of their daily life, like going out, socialising, and managing routine tasks can become even more difficult. Dementia combined with sight loss can lead to:
- Disorientation – People have a difficult time using visual cues in their environment to figure out their own location. This inability to understand where they are and being disoriented often provokes distress, agitation and sometimes even aggressive behaviour. Just imagine how scared and uncomfortable you would feel if you couldn’t make sense of your surroundings!
- Loss of safety and independence – Symptoms of dementia combined with poor sight can affect a person’s ability to move around safely and independently. It increases their risk of falling and can make activities of daily living more difficult to manage on their own. Sometimes the focus on the person’s safety means their independence can get lost. Compensatory mechanisms may not get placed to promote independence as the risk of sight loss is prioritised.
- Accepting multiple losses – Accepting the diagnosis of dementia is an emotional process in itself, so accepting a second loss of sight loss can truly be overwhelming for the person to cope with and might go into denial.
- Risk of isolation – Misidentifying and misperception of people, activities and objects can lead to social isolation. This may result in the person with dementia no longer wanting to attend social gatherings in fear they will embarrass themselves.
- Caregiver burden – Many people with dementia and sight loss are wholly dependent on their carer and family for orientation and stimulation as well as their everyday care. There is increased anxiety and worry for carers and their entire family.