Home' Australian Ageing Agenda : AAA Jan-Feb 2017 Contents Meredith Gresham
ision is critical to finding our way about
and functioning in our environment. Vision
becomes more critical as memor y declines
with dementia. Our visual systems will be
affected by all forms of dementia but the magnitude
and severity of problems var y with type of dementia.
Posterior cortical atrophy, dementia with
Lewy bodies and Alzheimer’s Disease, Visual
Variant are three types of dementia that will
primarily affect visual perception.
For other types of dementia visual processing
may be less affected, but damage to other structures
in the brain can produce visual–like symptoms.
Dementia affects widely differing areas of
the brain to produce idiosyncratic deficits. Here
are six of the more common visual problems
experienced by people living with dementia.
1. Visual acuity
Visual acuity is our ability to see clear both close
up and in the distance. Nearly all of us require
glasses as we age but studies have shown that
people with dementia have worse visual acuity
than other people of the same age.
Helping maximise visual acuity can be
achieved through simple inter ventions such as
treating eye conditions that are treatable.
Ensure eye glass prescriptions are up to date,
glasses are worn and they are clean. Appropriate
lighting is probably the single biggest impact
inter vention we can use in environments for
people living with dementia along with judicious
use of contrast to highlight what needs to be seen.
2. Other visual dysfunction
This includes issues such as distorted vision;
reading difficulties from the inability to perceive
groups of letters as words; blurred vision; loss
of parts of the visual field; lack of recognition of
faces and visual-spatial impairment, which is a
particular issue with driving. These sorts
of visual deficits are rarely assessed for.
3. Contrast sensitivity
Contrast is the difference in
brightness and colour that
makes an object stand out from
its surroundings. In dementia
our ability to detect changes in
contrast is impaired, that is to
see where the edge of a step is on
a flight of stairs or where a handrail
is when painted the same colour as the
In the first of a two-part series, MEREDITH
GRESHAM outlines some common dementia
and age-related changes to the brain and eyes
that disrupt visual processing.
Our vision is affected by all forms
of dementia but to varying degrees
wall behind. Better levels on non-glare lighting and judicious use of colour
can highlight what needs to been seen.
4. Poor motion perception – optic flow
In dementia and glaucoma (cause by higher pressure within the eye) optic
flow becomes disrupted, with the individual finding it difficult to position
themselves or confidently move through spaces.
5. Poor depth perception
People with dementia often will not perceive depth cues accurately. Colour
choice can exacerbate poor depth perception as dark colours recede and light
colours appear closer. The use of dark stripes or patterns on floors may cause
the person to perceive steps or holes in the floor or areas of light flooring
next to darker areas may be seen as a step up.
6. Poorer colour discrimination
The ability to discriminate colour diminishes in the ageing eye, especially
in the blue-violet range. However, studies have found that colour
discrimination diminishes to a greater extent in people with dementia. Small
changes in colour will probably not be seen. The use of more saturated
tones is necessar y if colour changes are to be perceived.
Almost ever yone with a dementia diagnosis will have difficulty processing
visual information. For some, especially younger people with dementia this
may be acute and ver y disabling.
Environmental adaptations are essential to improving the quality of
retinal information to help the brain process visual information
With environmental modifications, it’s important to:
• increase illumination by making it bright and evenly
distributed, reducing glare;
• use tonal contrast effectively to highlight required items;
make them stand out from their background (think of
cutler y, crocker y, towels, toilet seats)
• help spatial orientation by judicious use of high contrast
(in skirting boards and architraves, kerbs and stair tread
edges, seats on chairs and chairs on walls) and low
contrast (such as in flooring transitions) n
Meredith Gresham is head of research and design at
HammondCare’s Dementia Centre.
The second part of
Meredith’s series looks at
design solutions, including
the impact of effects like
contrast and colour –
appearing in the
next issue of AAA
australianageingagenda.com.au | 51
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