Seeing is a complicated process that involves many different stages. Information is transmitted from your eyes to your brain where it is then interpreted, alongside information from your other senses, thoughts and memories. You then become aware of what you have seen (it is ‘perceived’). Problems that involve both vision and perception can be referred to as ‘visuoperceptual difficulties’. As there are many different stages involved in the seeing process, various types and combinations of mistakes can occur.
There are many visual challenges which are part of the normal aging process including reduced sharpness, problems with depth and perception, pupils becoming smaller etc. However, eye conditions that can affect visual perception include cataracts, glaucoma, macular degeneration and retinal complications from diabetes. Your loved ones with dementia may also experience visual challenges as well.
A distortion of reality
This may be due to lack of contrast, or too much shininess or seeing something that is not there or real, due to colours/shapes. Your loved one may become frightened of carpets or busy designed walls.
Misinterpretation: what your loved one sees is a ‘best guess’ at the inaccurate or distorted information the brain has received from the eyes. This is usually from damage to the actual visual system – not the interpreting part but due to the information that gets there. Shadows for example may be mistaken for a hole in the ground.
Misidentification: Damage to the part of the brain responsible for identifying objects and familiar faces, this could also be due to expressive aphasia, and one could think that it is due to the eyes. Confusion between a husband and a son/ not knowing what the function of a tap is – not recognising the shape/object.
Some people with Alzheimer’s are affected by motion blindness and are unable to sense movement. For these people they view the world as a series of still frames, rather than a “movie” that most people see. Doctors have theorized that this view of the world causes affected persons to become lost, even in familiar surroundings.
Your loved one may have difficulty reaching for things within their visual environment such as a cup of tea or mistake images on TV for real people. They will also tend to avoid shiny flooring because it appears wet or slippery. Some people living with dementia may not even recognize themselves in the mirror if they are visually challenged.
Suggested guidelines
- Lock away any hazardous materials and liquids, childproof cupboards where hazardous materials are in and hide locks. Removes small free standing lamps, rugs and coffee tables.
- Remove rugs and wall papers that are too busy or that could be mistaken for stairs or a hole.
- Diffuse sharp light by removing mirrors and glass tops.
- Always introduce yourself to a person with dementia, especially if they have visuoperceptual problems.
- Always be in their visual field- especially when giving food, or if you want someone to see something specific.
- When in a new environment, rather let your love one follow you or give physical touch for safety.
- Hang up objects when you get inside the room. Make sure you have specific places for objects.
- Install strips of lights to guide the person when going to the bathroom