Dementia and serious sight loss

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Occasional paper Number 11

February 2007



Dementia and serious sight loss



This publication summarises findings from a research review conducted by
Professor Roy Jones and Dr Richard Trigg at the Research Institute for the Care
of the Elderly, St Mart
in’s Hospital, Bath.

Summary

This paper presents a review of the information available from research and

other
sources on people who have both dementia and serious sight loss. The review
included topics such as the number of people affected by both condi
tions, the
problems that those with both conditions may face, and areas where intervention
may lead to improvements in quality of life. The review was carried out in 2004 by
staff at the Research Institute for the Care of the Elderly in Bath. A

similar rep
ort
had been prepared for the Thomas Pocklington Trust in 1999 and it was felt timely
to review the situation. The later review took the form of a wide
-
ranging search of
the medical, scientific and social sciences literature for the period 1981
-
2004.

Amon
g the findings were that:



there has been no comprehensive study covering the area of sight loss and
dementia.



although significant sensory problems such as serious sight loss are not
part of the standard diagnostic features of Alzheimer’s disease, resear
ch shows
that there are changes in vision and visual processing that may be relevant. It is
important to diagnose both dementia and sight loss in order to maximise the
treatment and care of the individual.



the degree to which a person with dementia is abl
e to cope is likely to be
influenced by sight loss.



the effect of having both serious sight loss and dementia at the same time
is much more severe than the difficulties caused by either condition alone.



the environment plays a significant role in the deg
ree of disability
experienced by a person with sight loss and dementia. Some of the environmental
aspects that should be considered in order to

minimise

the effects include lighting,
use of colour and contrast, surfaces and textures, physical aspects of th
e building,
enhancement and camouflage, noise and the use of sound and inconsistent or
misleading cues.



no specific figures have been identified concerning the numbers of elderly
people with both dementia and sight loss.
It is, however, possible to make a

rough
estimate, based on data for the individual problems. Combining these figures, it
appears likely that about 2.5% of people over the age of 75 will have dementia and
significant sight loss.



it seems clear that a better understanding of the relationsh
ip between visual
processing and dementia is essential and that tangible benefits may arise from this
knowledge.


In view of the above, this paper suggests a number of areas relating to dementia
and sight loss in which research might be carried out.

Back
ground and context

Dementia is an acquired and progressive problem that affects thinking processes,
the ability to carry out everyday activities, and

behaviour
.

Vision

is one

of the
primary senses and serious or complete loss of sight also has a major imp
act on
a person’s ability to communicate effectively and function independently. There
will inevitably be profound practical, emotional, financial and psychological effects
for a person who has both dementia and seriously impaired vision, and these
effects

will extend to their family and to society. Both problems are more common
as people get older.

With the ageing

of our population and

in particular the
increase in the number of very old people (over the age of 80), it is inevitable that
dementia and serio
us sight loss, either alone or together, will have important
consequences for all of us.


Dementia

Dementia is one of the most important causes of disability in elderly people and
age is the main risk factor. Alzheimer’s disease is responsible for half t
o two
-
thirds
of all cases in adults whatever their age.

Vascular dementia (as

a result

of stroke
disease or problems with cerebral circulation) is responsible for 10
-
20% of cases.
Dementia with Lewy bodies and dementia associated with Parkinson’s disease i
s
responsible for another 10
-
20% of cases. Dementia with Lewy bodies is still under
-
recognised but it is of particular interest because people with this condition not
only show fluctuating cognition and confusion, together with features of mild
parkinsonis
m, but they also have problems with visual hallucinations.

Most people are aware that dementia affects memory,

but

it

is the impact on
performance

of daily activities and problems with

behaviour

(including aggression,
agitation and sleep disturbance) that

cause particular difficulties and lead to

institutionalisation
. Early in dementia the affected person, their friends and family
can often help

by using reminders. Later, people lose the

skills they

need

for
everyday life and they may fail to

recognise

fam
ily members. Eventually the brain
ceases to direct activities and the person becomes totally dependent on others.
The person may become bed
-
bound and unable to resist infection. Dementia not
only affects the individual with the condition but also their fam
ily, friends and all
who care for them.

Serious sight loss

Serious sight loss usually results from disease or an accident. In the UK, loss of
sight most frequently happens later in life and as part of the ageing process.
Recent figures
1

suggest that more

than 12% of people over 75 have some sight
loss. Visual acuity is reduced by 10% for 60
-
69 year olds, 30% for 70
-
79 year
olds and 35% in the over
-
80s.
2

The ability to perceive depth can be affected, and
there may be a reduction in the field of view. These

factors can make older
people vulnerable to falls.

One of the commonest causes of visual impairment in old age is macular
degeneration, which affects the central vision. The macula is the most sensitive
part of the retina and is essential for tasks requi
ring fine discrimination, such as
reading. Macular degeneration necessitates the increased use of peripheral
vision; optical aids that magnify can be very helpful, as the larger the image the
more likely it is to fall on the unaffected area and be seen. Ot
her conditions
commonly affecting vision in older people are cataracts, glaucoma and diabetic
retinopathy.

Two conditions which may reduce the visual field, thereby impairing peripheral
vision, are glaucoma and retinitis pigmentosa. This may lead to tunne
l vision,
when the person can only see what is immediately in front of them. Getting
around is a particular problem for people with tunnel vision because it makes it
more difficult to spot potential hazards.

Dementia occurring together with serious sight
loss

Some conditions can cause both visual and cognitive impairment, including
multiple sclerosis, Down’s syndrome, diabetes and serious head injuries.
However,

in most cases the problems

of dementia and serious sight loss develop
independently.

As people

age they are at an increased risk of developing
dementia and of having serious sight loss, so there will inevitably be a number of
people with both problems.

Methods

This report has reviewed information obtained from a wide
-
ranging search of

the
medical
, scientific and social sciences literature for the period 1981
-
2004. These
searches produced approximately 1,000 hits, from which 150 references were
identified as of potential relevance and a final selection of 70 references
examined in full. No comprehe
nsive study whatsoever was found covering the
area of sight loss and dementia.

In addition a number of UK reports that cover the relevant area, for example
several reports by the Royal National Institute of the Blind (RNIB), were consulted
together with a

wide range of individuals and organisations. Information was
obtained from the RNIB and the Alzheimer’s Society websites. An internet search
was carried out using the search engines ‘Yahoo’ and ‘Google’, but this did not



1

Eva
ns JR, Fletcher AE,

Wormald

RPL
et al

(2002)
Prevalence of visual impairment in people aged75 years

and older

in Britain:
results

of

the

MRC

Trial

of Assessment

and Management

of Older People in the Community
, British Journal

of Ophthalmology,86:
795
-
800.


2

Morris

C

(1999) Visual impairments and problems with perception, Journal of Dementia and Care, Nov/Dec: 26
-
28.

bring up any new directly relevant

data.

Results

Visual processing in dementia

Although significant sensory problems such as impaired vision or hearing are not
part of the standard diagnostic features of Alzheimer’s disease, recent research
has shown that there are changes in vision and

visual processing that may be
relevant. There is also evidence of significant disturbances in visual function in
some other types of dementia. For example there may be problems with visual
acuity, contrast sensitivity, colour vision and stereo
-
acuity.

In
general these deficits
are believed to be more reflective of disturbances in the brain than any specific
problems in the eye or optic nerve.

A

visual variant of Alzheimer’s disease, Posterior Cortical Atrophy (PCA), has
been reported in a small number of
people who develop a progressive decline in
visual processing out of proportion to the difficulties in other aspects of cognition
and thinking processes. It results in a range of complex visual disturbances and
patients may have relatively intact insight i
nto their problems, often complaining
vehemently about their visual decline and showing high rates of depression.

There is a clear link between impairment in visual acuity and the occurrence of
visual hallucinations. Despite this, one study demonstrated t
hat few dementia
patients with hallucinations had undergone recent visual assessment. The
suggestion has been made that there is enough of a link between reduced vision
and hallucinations in dementia to warrant a study to examine the value of
improving vis
ion for these people.

It seems clear that more research should be done into the relationship between
visual processing and dementia, and that tangible benefits may arise from this. For
example, it might be possible to improve the visual environment and fu
nctional
capacity of people with dementia, and information about visual disturbances in
Alzheimer’s disease might be useful in the care and understanding of the
problems of individual patients.

Number of people affected

No specific figures for the number
s of people with both dementia and sight loss
were identified from the literature review. One UK study
3

reported impaired vision

in

30 (28.8%) out

of

114 community resident people with dementia in comparison
with
36 (34.6%) in a control group matched for a
ge and sex. These differences
were not significant. A study of sight loss in nursing home residents in Australia
concluded that residents with dementia were more likely to have blindness (13%)
than those without dementia (9%). These results must be interpr
eted cautiously
because of the small numbers of subjects in the study, and because blind people



3

Philp I, McKee KJ, Meldrum P et al (1995) Community care of demented and non
-
demented elderly people: a comparison study of
financial burde
n, service use, and unmet needs in family supporters, British Medical Journal, 310: 1503
-
1505.

with dementia are more likely to need nursing home care than those without
dementia.




Number of people with dementia

There are numerous studies in the litera
ture assessing the prevalence of
dementia, and several reviews have been published. A

reasonable figure for

the
prevalence

of dementia

in people

over 75 is 15% of the population. The
Alzheimer’s Society website suggests that 775,200 people in the UK have
d
ementia, based on the population figures for 2001. The Alzheimer’s Society
suggests that the prevalence for dementia

in 65
-
70 year oldsis1in 50, for 70
-
80
year olds1in20and for the over
-
80s1in5.Itis estimated that by 2010 there will be
approximately 840,00
0 people with dementia in the UK.

Number of people with serious visual impairment

The RNIB estimate that up to 16% of people over 75 may be blind or partially
sighted, whilst prevalence estimates of sight loss from the MRC

Trial

of
Assessment and Managem
ent

of Older People

in the Community gave a lower
figure of 12.4% for low vision and blindness. This study
4

examined the levels of
visual impairment in 14,600 people aged 75 years or older recruited from 53
practices in the MRC General Practice Framework.

The visual acuity of participants was measured and rates of low vision and
blindness calculated. Of the people aged 75
-
79 years, 5.6% had low vision and
0.6% were blind; among those over 90, 30% had low vision and 6.9% were blind.
The results confirm that

sight loss is common in this age group and that the risk of
low vision and blindness increases steeply with increasing age. Using population
estimates from the UK, the authors estimate that approximately 506,000 older
people living in the UK have low visi
on, of whom 128,000 are over 90 years old.
Similarly they estimate that there are, in addition, approximately 103,000 blind
people of whom 29,000 are over 90 years old. The authors suggest that their
estimates of sight loss are likely to be lower than the
real figures because:

a) they did not measure visual fields (and visual field loss can

contribute considerably to the burden of sight loss and blindness)

b) people in long
-
term nursing care were excluded (other studies

have reported higher rates of sig
ht loss in the nursing home

population compared to a community sample) and

c) older people and women were less likely to be examined in the

study (and these groups contain the highest levels of sight loss).

Importantly, the authors also concluded that
a substantial proportion of sight loss
in their sample of older people was caused by refractive error and cataract, both
of which have safe and effective interventions.




4

Evans

J et al (2002) op. cit.



Number of people with dementia and serious sight loss

It is possible to make a rough

estimate of the number of elderly people who have
dementia and sight loss based on the data for the individual problems, although
such an estimate will obviously be affected by the accuracy of the data available
with regard to sight loss and dementia for
any given population.

A

reasonable
figure for the prevalence of dementia in people over 75 is 15% of the population.
The RNIB estimates that up to 16% of people over 75 may be blind or partially
sighted. The prevalence estimates of sight loss from the MRC
study give a lower
figure of 12.4%, although this may be an underestimate, as previously
mentioned. Combining these figures together it would appear that about 2.5% of
people over the age of 75 are likely to have dementia and significant sight loss.

This
figure is likely to be conservative. The links between dementia, particularly
Alzheimer’s disease, and visual problems highlighted earlier

in this report
suggest that

the prevalence

of

sight

loss

is

likely to be higher in people with
dementia than in non
-
d
emented older people. There are also likely to be people
with dementia who have visual impairments that have not been detected due to
the problems of assessment of vision in people with severe cognitive problems.
Both the RNIB figure of 16% and the Evans e
stimate of 12.4% will not account
for individuals who were deemed ‘untestable’, and it is likely that this group
would have included subjects with dementia.

A

much higher figure has been
suggested

in one cross
-
sectional survey of visual acuity in elderly B
ritish people.
In this study, visual acuity was successfully measured in 125 people classified as
mentally impaired by a memory test; nearly 65% of these participants appeared
to have low vision. However, the authors added that it was ‘unclear to what
exte
nt true visual disorders are responsible and to what extent the poor mental
capacity of these subjects influenced the results’. They concluded by
recommending further study of sight loss in cognitively impaired people in order
to determine the needs of thi
s particular group.

Sight loss and dementia in different residential
settings

Dementia

Around 40% of people with dementia are resident in institutions of various types.
One study
5

based on data from 1996 demonstrated that men and women with
dementia wer
e over 30 times more likely to live in an institution than people
without dementia. At 65, men with dementia are three times more likely than
women with dementia to live in an institution. At 86, men and women are equally
likely to be living in an institut
ion. After a 5
-
year follow
-
up study

of people85 years
and older,

it was shown than 16%of men with dementia had survived in
comparison with 44% of men without dementia, and 27% of women with dementia
had survived compared with 52% of women without dementia.





5

Launer LJ, Anderson K, Dewey ME, Letenneur L, Ott A, Amaducci LA, Brayne C, Copeland JR, Dartigues

JF, Kragh
-
Sorensen

P,
Lobo

A, Martinez
-
Lage JM, StijnenT,

and Hofman

A

(1999)
Rates and Risk Factors for Dementia and Alzheimer’s disease: results from
EURODEM pooled analyses
. Neurology,52: 78
-
84.

Sight loss

There were no reports giving a detailed breakdown of the numbers of people with
sight loss in different residential settings. An RNIB survey from 1991 reported that
45% (346,000) of people with sight loss live on their own. The percentage
inc
reased incrementally with age from 19% for the under
-
60s to 40% of those
aged 60
-
74. Among those aged 75 and over who carry the double burden of
extreme old age and reduced vision (and in many cases other handicaps as well),
50% lived on their own.

The RN
IB estimated that 21% of registrably visually impaired people live in
communal establishments. Among those experiencing disability,

it was generally
those aged75 or over who lived

in institutions.

A

higher prevalence

of sight loss
has been reported

in olde
r people living in institutions compared to a general
community sample. It was reported that 9.9% of community
-
dwelling individuals
over 65 had sight loss as opposed to 35.6% of people in institutions. The authors
suggest that this discrepancy may imply th
at sight loss is an important factor
contributing to nursing home placement.

Sight loss and dementia

Some studies were identified that included details of the numbers of people with
sight loss and dementia in different residential settings.
In a large ep
idemiological
survey of elderly people and their carers in the London borough of Islington, 8%
(56/700) lived in sheltered accommodation whereas 92% (644/700) lived
independently. The mean age of those living in sheltered accommodation was 81
years and for

those living independently 75 years.
Of those living in sheltered
housing, 8.9% (5) had dementia in comparison with 5.2% (34) of those living
independently. Although there was no significant difference in the prevalence of
dementia between the two groups,

there were significantly more symptoms of
dementia in those in sheltered accommodation.

The numbers of people with visual problems found in this study were as follows:
22.2% (143) living independently had poor vision (glasses), 15.4% (99) needed
large pr
int books and 4.3% (28) were blind. Of those living in sheltered
accommodation, 44.6% (25) had poor vision, 37.5% (21) used large print books
and 0.8% (1) was blind. There were very few severe visual problems in this survey
so that meaningful comparisons a
re difficult.

The Blue Mountains Eye Study
6

is a population
-
based survey of vision and
common eye diseases in people aged 50 or older in two postcode areas west of
Sydney. Data from the community has been compared with data from nursing
homes in the area.

Nursing home examinations were conducted during 1993. Of
the 128 nursing home residents eligible for the study,

88(69%) had dementia
(mostly Alzheimer’s disease). Five refused any examination, and dementia
prevented an accurate visual acuity assessment in

another 34 of the 88 with
dementia, leaving 89 residents (35 without dementia) in whom visual acuity could



6

Mitchell

P, Hayes

P

and

Wang

J(1997) Visual impairment in nursing home residents:
the Blue Mountains Eye Study, Medical Journal
of Australia, 166:73
-
76.

be assessed. Severe sight loss or legal blindness was present in 10 of the 89
nursing home residents (11%). Residents with dementia had a slightly i
ncreased
prevalence of blindness (13%) in comparison with those without dementia (9%).
Across age strata, nursing home residents were five times more likely to be blind
than community residents. Moderate sight loss was also more prevalent among
nursing hom
e residents in all age groups.

Dementia was the most common reason for nursing home placement. Sight
loss was a common disability among nursing home residents. One
-
third had
significant sight loss or blindness and among those whose vision could be
measure
d, 11% were blind. It was not possible to determine how frequently
sight loss influenced the decision on nursing home placement.

Behavioural agitation (physical aggression and disruptive vocalisations) is very
common in nursing home residents. Research ha
s indicated that both cognitive
impairment and sight loss may contribute to agitation. One study found that
hearing impairment, sight loss, cognitive status and gender were all independent
predictors of agitation. The authors of the report stated that thei
r results needed
replication and commented that future studies should use audiologists and
optometrists to carry out detailed evaluations of sensory limitations.

Difficulties in assessing people with both problems

It is important to diagnose both dementi
a and sight loss in order to maximise
the treatment and care of the individual. As drug treatments become available
for people with dementia, accurate and earlier diagnosis is increasingly
important. Similarly the early diagnosis of eye conditions is essen
tial so that
treatment can be commenced and further deterioration in vision prevented
where possible.

Diagnosis

of dementia usually involves

tests

of memory

and cognition (thinking
processes). Such tests are usually in the form of questions and answers an
d use
written, verbal and visual material.
The Mini
-
Mental State Examination (MMSE),
the most widely used brief cognitive test, is used as an indicator of dementia.
The
most common cause

of poor performance on this test, other than dementia, is
poor vision

or blindness.

One paper recognised that there is a problem applying the MMSE in very old age
where there may be sight loss. The authors tested the complete MMSE and the
MMSE without the vision
-
dependent items (the MM Blind) to see whether the
MMSE loses
its discriminative power when vision
-
dependent items are omitted.
The MM Blind scores for people with sight loss were found to be no less valid than
the full MMSE. Items of short
-
term memory, orientation and calculation are still
contained within the MM Bl
ind, which deserves more widespread
application. It

may
also be

necessary to

develop other tests to overcome such problems.

Standard tests of vision rarely seem to be carried out when people are assessed
for dementia. In addition, a person with dementia m
ay find it difficult to describe
problems and fluctuation in visual functioning. Difficulties in testing vision in
cognitively impaired people have been acknowledged.
7

This may mean that vision
-
threatening conditions are missed in individuals with dementia
, as many are
deemed untestable by conventional means. The relative benefits of two methods
of visual acuity testing were tested in a sample of nursing home residents with
cognitive impairment. Standard recognition acuity tests were compared to a test
usin
g cards containing stripes of different widths (Teller cards) based on
preferential looking, which has been used in children. In 656 people recruited, 566
were testable in one eye with either or both methods.

Of these 566, 84% were
testable

by

Teller cards

whereas 73% were testable by standard means. Of those
individuals with a MMSE score of below 10 reflecting severe impairment, 61%
were testable using

Teller cards whereas 41% were testable

by standard means.
The results

of the

Teller card test correlated
highly (r=0.79) with a standard
recognition acuity test. The authors concluded that although some people may be
untestable due to severe cognitive deficits, visual acuity screening could be
completed in approximately 79%of residents. The

Teller method base
d on
preferential looking may be more suitable for people with cognitive impairment,
especially if they are untestable by conventional means.

There is also evidence from the literature suggesting that visual problems may
contribute to poor performance on
tests of cognitive function, and vice versa. It is
important, for example, to ensure that an elderly person is tested in conditions
where the lighting is adequate otherwise it may be wrongly assumed that they
have significant cognitive impairment when the
problem is merely due to poor
vision under these circumstances.

It is clear from both the literature search and the comments of the people
consulted in association with this report that it is vital for eyesight to be optimal in
people who also have dement
ia.

Problems with having both conditions

The degree to which a person with dementia is able to cope is likely to be
influenced by sight loss and vice versa. For example, people with dementia have
an increased risk of falls, as do people with significant
loss of vision. The risk of
falls is increased in people with impaired depth perception and impaired contrast
sensitivity. Both of these are factors that may be altered by conditions such as
Alzheimer’s disease. People affected by both conditions may be mo
re susceptible
to noise and changes in light intensity, and have difficulty in understanding and
learning how to use new equipment. The use of compensating mechanisms to
help people with sight loss to overcome their visual deficits will be significantly
af
fected by problems with memory and thinking processes.

There is an additional problem in assessing agitation in nursing home residents
with dementia and sensory impairment. The question was raised whether care
staff are well enough trained to understand t
he behaviour of people with dementia
and sight loss, and whether traditional observational methods such as Dementia



7

FriedmanDS, MunozB,WassofRW, Bandeen
-
RocheK,WestSK (2002) Grating visual acuity using the preferential
-
looking method in
elderly nursing home residents, Investigative
Ophthalmology

&

Visual

Science, 2572
-
2578.

Care Mapping are appropriate. Dementia Care Mapping is an observational
procedure carried out in institutional settings that observes the na
ture and degree
of interaction between the person with dementia and the staff. It may be that a
person with dementia and sight loss behaves

in

a

different way from

a

visually
able person with dementia. This could lead to behaviours being misinterpreted.
Fo
r example, an apparent protective effect of sight loss on agitation in nursing
home residents with dementia has been reported, but this could be because the
agitation is expressed in different behaviours, rather than because sight loss
causes the person to

become less agitated. An agitated person with dementia and
sight loss may be more likely to sit motionless due to increased disorientation and
the need to concentrate on sounds around them. It is suggested that an improved
awareness is needed of the diffe
rent ways in which sight loss may affect the
person with dementia.

The effect of having both serious sight loss and dementia at the same time is
much more severe than the difficulties caused by either condition alone. Learning
how to compensate for the di
fficulties caused by loss of sight is even more difficult
in the presence of dementia, and vice versa. How easily a person overcomes the
difficulties due to both conditions depends on a number of factors. Each person
with sight loss and dementia is unique,

with differing degrees of sight loss and
dementia, as well as differing needs, abilities and expectations. Each person
receives a different amount of support and help. It is therefore difficult to develop
firm guidelines on what to expect with someone who

has both conditions. Some
people may cope with loss of memory and sight better than others.

Problems with visual acuity, contrast sensitivity, colour vision and stereo
-
acuity in
the person with dementia do have an effect on cognitive performance and
acti
vities of daily living, and may contribute to the appearance of hallucinations.
The combination of dementia

and serious sight loss

is likely

to

be

an

overwhelming personal and family catastrophe affecting the person’s mobility,
work, personal relationships

and much besides. Anxiety and depression are likely
to occur, together with a decline in self
-
esteem and sleep disturbance.
Communication and intense social isolation appear to be particular problems.

Dementia causes both expressive and receptive languag
e problems, making it
harder to communicate effectively. Problems include word
-
finding and naming,
comprehension and sentence construction. The impact of dementia on language
and communication will vary according

to

the type and severity

of dementia and
al
so the presence of sensory impairment such as sight loss. The communicative
problems experienced by someone with dementia will undoubtedly be increased
by significant sight loss. It has been suggested that such individuals should ideally
have access to a s
peech and language therapist in order to chart comprehensively
the pattern of difficulties, the areas of preserved ability and the ability to employ
compensatory strategies.

People with dementia experience increasing difficulty with the performance

of
eve
ryday activities and there

is

a gradual loss

of functional independence.
Functional independence has been found to be an important factor in maintaining
quality of life in dementia. Loss of functional independence is not only a key issue
for the person wit
h the disease, but it can place an increased burden on carers
and precipitate a move to residential or full
-
time care. Sight loss, especially loss
of contrast sensitivity, can also have a significant impact on functional
performance. Research suggests that

reduced contrast sensitivity is the best
predictor of disability affecting activities of daily living when other factors such as
age and motor limitation are controlled. This is especially true for outdoor mobility
and facial recognition.

People with dem
entia have an increased risk of falls. Similarly, sight loss
significantly increases the incidence of falls amongst older people.

A

key
component

of postural stability

is visual function, and key factors in predicting
falls appear to be visual acuity and c
ontrast sensitivity.

In situations where there

is

a greater dependence on vision for stability (such as when the person has
balance problems or when in a novel environment), sight loss is likely to
contribute to an increase in falls. Older people rely more

on visual information to
control posture than younger people, who tend to rely on proprioceptive reflexes.
Both cataract and problems with visual acuity have been associated with an
increase of falls in patients with Alzheimer’s disease.

The environment
plays a significant role in the degree of disability experienced
by a person with sight loss and dementia. An RNIB booklet on improving
environments for people with dementia and sight problems is one of the few
publications that address some of the environ
mental issues for people with both
conditions. It provides a brief overview of the main issues including:



Noise


people who are confused may not be able to interpret sounds
correctly or understand spoken words. They may become distressed by
noises that m
ake no sense to them.



Lighting


changes in light intensity from day to day can cause
disorientation as things will look different. It is also more difficult for older
people to adapt to disparities in lighting within the environment and
shadows can prese
nt difficulties for confused individuals and may be
misinterpreted. There is a need for appropriate night lights that lead the
person to the toilet and then back to bed.



Equipment


there may be problems understanding and learning new
things. Controls on
equipment need to be clear and easy to use. Equipment
needs good colour contrast to its surroundings but must still be easily
recognisable.



General environment


the design of the environment and the extent to
which appropriate signs and guides are availa
ble will determine how easily
people are able to move around.

Varying textures and colours on flooring
and surfaces can often provide misleading information.



Enhancement and camouflage


differing contrast between objects and the
background can make thing
s more visible or be used to hide objects to
reduce risk.



What can be done to help?

There are many areas where research, development and education can
contribute to improved care for people with dementia and serious sight loss.

A

better understanding

of

the experiences and needs of people with dementia and
sight loss will improve the quality of care available.

There are many unresolved issues surrounding the assessment of sight loss and
cognitive impairment in people with both dementia and sight loss. T
here is a
need to develop measures that are appropriate and simple to administer,

to
ensure that regular assessment for both conditions is possible. One important
area is to adapt the design of appropriate environments for people with dementia
and sight lo
ss. The literature suggests many areas where informed design can
benefit the health and quality of life of people with these conditions.

The RNIB booklet previously mentioned described seven components that should
be looked at when assessing the appropria
teness of the environment. These
include lighting, use of colour and contrast, surfaces and textures, physical
aspects of the building, enhancement and camouflage, noise and the use of
sound, and inconsistent or misleading cues. These general principles of

design
are suggested as a basis for care staff to assess the environment for people with
dementia and sight loss.

Lighting is a key issue for people with dementia and sight loss. The light
requirement for old people may be as much as five times greater t
han for the
young. Knowledge of human vision and lighting design should facilitate thoughtful
lighting to enhance mobility and alleviate the fear of falling. Outdoor light levels
can be 100
-
1000 times greater than interior light levels during the day. Smal
ler
and less elastic pupils in older adults mean that, when coming inside from natural
daylight, there is a slowing in visual adaptation. It can take from five to 30 minutes
for an elderly person’s eyes to adapt to this change. The glare from bright lighti
ng
can be difficult for people with visual problems. Efforts should be made to control
natural light and glare indoors without shutting out valuable light or using reflective
surfaces (such as tinted windows), which can cause agitation and confusion in
dem
ented individuals who perceive them not as reflections but as unidentified
individuals in the room.

Conclusions and suggestions for potential research
projects

There is a lack of formal research on this population. Information on people with
dementia and

sight loss can generally only be found in studies examining one of
the two conditions. Few documents address the characteristics and needs of
people with dementia and serious sight loss, yet both problems are common

in

older people


particularly those in

residential and nursing homes. There are a
number of areas for potential future research:

Area 1.

Epidemiological studies. There is a dearth of reliable data on the
population in the UK with both sight loss and dementia. However, any significant
epidemio
logical study is likely to be quite expensive. People suspected of having
dementia are often referred to an outpatient memory clinic, and a study that
formally assesses the vision of such patients could be useful.

Area 2.

The effectiveness of routine asse
ssment.
The RNIB recommends that
people with multiple problems should have their vision assessed regularly. It
would be useful to identify assessment policies and resources in different settings
and assess their effectiveness in reducing the burden of sigh
t loss in people with
dementia.
The development of appropriate assessment policies could also be
considered where no such policy currently exists.

Area 3.

The needs of people with dementia and sight loss. At present there is
little information from resear
ch that enables us to understand better the
experiences and needs of people with dementia and sight loss. Qualitative work
to identify quality of life issues would be helpful; including comparisons between
the needs of people with dementia alone or sight l
oss alone, with those with
combined problems.

Area 4.

Optimising vision

in people with dementia.

A

systematic review of the
literature on cataract surgery and other measures in people with cognitive
impairment would be of interest. It would be useful to r
eview the attitudes of
ophthalmologists and opticians to eye surgery and correction of visual
abnormalities in people with dementia. There is a need for research to assess the
impact of optimising vision on the occurrence and severity of hallucinations of
people with dementia.

Area 5.

Visual impairments resulting from dementia. Further research

would try
and understand the nature of specific abnormalities in conditions such as
Alzheimer’s disease that affect visual processing.

Area 6.

Development of educa
tional programmes to ensure that care staff are
trained sufficiently to understand the behaviour of people with dementia and
sight loss. New programmes could be developed and audited for their success
or otherwise.

Area 7.

Rehabilitation techniques. There

is a need to review current models of
rehabilitation that may not be suitable for people with dementia and sight loss.

Area 8.

Environmental design. Research to provide a comprehensive overview
of how care settings should be structured would be useful, a
nd should include a
review of the physical features of the environment but also other areas such as
activities, interactions and the opportunity for privacy and control.

Area 9.

The development of appropriate assessments. The testing of memory and
cogniti
on in dementia relies largely on tests that are visually based. Cognitive tests
are needed that are sensitive to the difficulties that can occur through impaired
contrast sensitivity or acuity.

Author

Professor Roy Jones

The Research

Institute for the C
are of the Elderly

St Martin’s Hospital Bath BA2 5RP



References

Evans JR, Fletcher AE, Wormald RPL et al (2002) Prevalence of visual
impairment in people aged 75 years and older in Britain: results of the MRC Trial
of Assessment and Management of Olde
r People in the Community, British
Journal of Ophthalmology,86: 795
-
800.

Morris

C

(1999) Visual impairments and problems with perception, Journal of
Dementia and Care, Nov/Dec: 26
-
28.

Philp I, McKee KJ, Meldrum P et al (1995) Community care of demented a
nd
non
-
demented elderly people: a comparison study of financial burden, service
use, and unmet needs in family supporters, British Medical Journal, 310: 1503
-
1505.

Launer LJ, Anderson K, Dewey ME, Letenneur L, Ott A, Amaducci LA, Brayne C,
Copeland JR, Da
rtigues JF, Kragh
-
Sorensen P, Lobo A, Martinez
-
Lage JM,
Stijnen T, and Hofman A(1999) Rates and Risk Factors for Dementia and
Alzheimer’s disease: results from EURODEM pooled analyses. Neurology, 52: 78
-
84.

Mitchell

P, Hayes

Pand

Wang

J

(1997) Visual impa
irment in nursing home
residents: the Blue Mountains Eye Study, Medical Journal of Australia, 166:73
-
76.

Friedman DS, Munoz

B,

Wassof

RW, Bandeen
-
Roche

K

,West

SK (2002) Grating
visual acuity using the preferential
-
looking method in elderly nursing home
r
esidents, Investigative Ophthalmology

&

Visual Science, 2572
-
2578.

How to obtain further information

A

full project report, entitled

Review: Dementia and blindness, Second Edition,
August 2004, by Professor Roy Jones is available from:

Thomas Pocklingto
n

Trust

5

Castle Row

Horticultural Place

London W4 4JQ

Telephone: 020 8995 0880

Email
info@pocklington
-
trust.org.uk



Web

www.pocklington
-
trust.o
rg.uk



Copies of this report in large print, audio tape or CD, Braille and electronic
format are available from Thomas Pocklington

Trust.


Background on Pocklington

Thomas Pocklington

Trust

is the leading provider

of housing, care and support
services
for people with sight loss in the UK. Each year we also commit around
£600,000 to fund social and public health research and

development projects.

Pocklington’s operations offer a range of sheltered and supported housing,
residential

care, respite

care,

d
ay services, home care services, resource
centres and community based support services.

A

Positive about Disability and an Investor in People organisation, we are
adopting quality assurance systems for all our services to ensure we not only
maintain our q
uality standards, but also seek continuous improvement in line
with the changing needs and expectations of our current and future service
users.

We are working in partnership with local authorities, registered social landlords
and other voluntary organisa
tions to expand our range of services.

Our research and development programme aims to identify practical ways to
improve the lives of people with sight loss, by improving social inclusion,
independence and quality of life, improving and developing service

outcomes
as well as focusing on public health issues.

We are also applying our research findings by way
of pilot

service
developments to test new service models and develop best practice.


Published by Thomas Pocklington Trust

5

Castle Row, Horticultur
al Place Chiswick London W4 4JQ

Tel 020 8995 0880

Email info@pocklington
-
trust.org.uk Websitewww.pocklington
-
trust.org.uk

Registered Charity No. 1113729

Company Registered No.
359336

Published

by Thomas Pocklington

Trust

ISBN 978
-
0
-
9554465
-
1
-
1