ROYAL NATIONAL INSTITUTE OF THE BLIND
THE NUMBER OF PEOPLE IN THE UK WITH A VISUAL IMPAIRMENT:
the use of research evidence and official statistics to estimate and
describe the size of the visually impaired population
Nigel Charles, RNIB
July 2006
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2
CONTENTS
List of tables
Summary
1.
Introduction - purpose and scope of the paper
2.
Defining visual impairment for the purpose of estimating
population size
3.
Children and working age adults
4.
The research basis of prevalence estimates and the causes of
visual impairment in older people
5.
Older people and general estimates
6.
Older people and the screening, treatment and estimates of
those with treatable visual impairment
7.
Older people, registerable visual impairment, gender and
independence
8.
Administrative counts of those registered - their reliability and
comparison with population estimates
9.
Summary and conclusions - the main findings and research
needs
10.
References
Appendix 1:
Visual impairment population estimates for England,
Wales, Scotland and Northern Ireland
Appendix 2:
Census measures of the UK population
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TABLES
TABLES
Table 1:
Table 2:
Table 3:
Table 4:
Table 5:
Table 6:
Table 7:
Table 8:
Table 9:
Table: 10
Table 11:
Table 12:
Table 13:
Table 14:
Table 15:
Table 16:
Table 17:
Table 18:
Table 19:
Table 20:
Table 21:
Table 22:
Table 23:
Table 24:
Table 25:
Table 26:
Prevalence and population estimates of
visual acuity (Age: 20-59 years)
Causes of visual impairment
Summary of UK prevalence estimates:
Summary of UK population estimates:
UK prevalence estimate of pinhole corrected
VA < 6/18 for those living in their own homes,
sheltered housing and residential and nursing homes
UK population estimate of pinhole corrected
VA < 6/18 for those living in their own homes,
sheltered housing and residential and nursing homes
UK prevalence estimate of pinhole corrected
VA < 6/18 (By type of accommodation and age group)
UK population estimate of pinhole corrected
VA < 6/18 (By type of accommodation and age group)
England (2003): Local authority counts of those
registered as sight impaired and severely sight impaired
Scotland (2003): Local authority counts of those
registered as sight impaired and severely sight impaired
Population estimates for visually impaired children
(by nature of sight loss and country)
Population estimates of visual impairment in adults
aged 20-59 years(by visual acuity and country)
Population estimates of specific eye conditions
amongst those aged 75 years and over with uncorrected
presenting binocular VA <6/18 (by cause of sight loss and
country)
England and Wales population estimates for all causes
of visual impairment amongst older people
Scotland population estimates for all causes of visual
impairment amongst older people
Northern Ireland population estimates for all causes
of visual impairment amongst older people
England and Wales population estimates VA < 6/18
Scotland population estimates VA < 6/18
Northern Ireland population estimates VA < 6/18
UK population size: age group by gender
UK population size for selected age groups
England and Wales population size: age group by gende
Scotland population size: age group by gender
Northern Ireland population size: age group by gender
UK population size: age group by accommodation type
UK population size: age group by accommodation type
and selective age groups
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Table 27
England and Wales population size: age group by
accommodation type
Table 28:
Scotland population size: age group by accommodation
type
Table 29:
Northern Ireland population size: age group by
accommodation type
ACKNOWLEDGEMENTS
Professor Astrid Fletcher, London School of Hygiene and Tropical Medicine,
provided considerable advice and comments in the process of drafting this
report.
Sue Keil (RNIB) provided a great deal of assistance in drafting section 3.
Professor Jill Manthorpe, Social Care Workforce Research Unit, King’s
College London provided useful comments on the drafting of the report.
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SUMMARY
1.Overview
Estimates of the size of the visually impaired population are derived from
samples of the general population. When using data gathered in this way, the
most appropriate estimate to use is the estimated range into which the true
population size is likely to fall as it is misleading to produce absolute
estimates of the size of the visually impaired population. The most recent and
most reliable epidemiological studies show that in the UK there are:
 up to 30, 000 visually impaired children.
 around 47, 000 visually impaired adults of working age.
 between 1.6 and 2.2 million visually impaired people aged 65 years and
over. Half of these have severe levels of vision impairment.
About 97% of the visually impaired population is aged 65 years and over and
about 57% are aged 75 years and over. This population is not an
homogenous one, especially the older part of it. This summary reports the
main known variations in this population1.
2.Children
Studies of visual impairment in children using epidemiological and official data
produce estimates of between 7, 000 and 30, 000 visually impaired children in
the UK. The variation depends on the definitions of visual impairment used:

Broad definitions of visual impairment in terms of qualifying for specialist
education and social services, related criteria and the ages used to define
children produce estimates of between 12, 000 and 30, 000 children
depending on the definition of visual impairment and the age limits used to
define children.
1
Estimates for the size of the groups covered in this summary for the countries in the UK are
shown in Appendix 1.
8

A definition of visual impairment restricted to the most severe forms of
impairment in children aged up to 16 years produces an estimate of
7, 000.
3.Working age adults
There are about 47, 000 visually impaired adults in the UK of working age
whose visual acuity (VA) corresponds to UK registration criteria. Registration
data are a reasonably accurate means of measuring visual impairment in the
working age population.
4.Patterns of visual impairment in older people
The estimates in this report use clinical tests of visual acuity to identify three
main groups of visually impaired older people. These groups consist of those
with:

Severe visual impairment (VA <3/60).

Moderate visual impairment (VA 6/18->3/60).

Mild vision impairment (VA 6/12->6/18).
Those with moderate or severe visual impairment are eligible for registration if
the cause of their impairment is due to a non remediable cause, such as age
related macular degeneration or glaucoma. People with visual impairment due
to conditions such as cataract or refractive error are not eligible for registration
since these conditions can be treated.
The term mild visual impairment is
used to refer to those whose visual impairment lies in the range in which a
person would not be considered for registration.
This review provides estimated numbers of:

All those with some degree of vision impairment ranging from mild to
severe.

Those with treatable causes of impairment.
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
Those with impairment caused by conditions likely to be eligible for
registration.
We have used the terms moderate or severe visual impairment to include
both those eligible for registration and those with treatable causes of vision
impairment. Care should be taken not to interpret the estimates for those with
moderate or severe visual impairment as those only eligible for registration.
Visual acuity and cause of visual impairment
The estimated range for the size of the older visually impaired population in
the UK is:
Mild vision impairment:
964, 000 - 1, 155, 000
Moderate or severe visual impairment:
676, 000 - 1, 036, 000
The main causes of impairment in about half of the second group are
untreated cataracts or refractive error and in the other half the causes are
conditions that cannot be cured such as age related macular degeneration
(AMD).
The estimated range in the UK for specific eye conditions amongst those
aged 75 years and over are:
Age related macular degeneration:
180, 000 - 216, 000
Glaucoma:
34, 000 - 52, 000
Diabetic eye disease:
8,000 - 17, 000
Vascular occlusions:
10, 000 - 21, 000
Refractive error:
155, 000 - 190, 000
Cataract:
119, 000 - 147, 000
The size of these populations can change. For example, if we assume that
prevalence does not change and that there are no improvements in the
treatment of age related macular degeneration, the ageing of the UK
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population means that there will be between 20, 000 to 24, 000 more people
aged 75 years and over with registerable AMD in the UK by 2020.
Age
The estimated ranges for the number of people in the UK with vision
impairment are:
65-74 years:
623, 000 - 943, 000
75-84 years:
542, 000 - 686, 000
85 years and older:
475, 000 - 562, 000
The likelihood of being visually impaired is substantially greater for those in
the oldest age groups of the older population. Over a quarter (26.8%) of those
aged 85 years and over have moderate or severe visual impairment,
compared with 5.6% of those aged 65 to 74 years and 8.5% of those aged 75
to 84 years. The population in the youngest of these age groups is greater
than in the older group because there are many more people in the general
population aged 65 to 84 years.
Gender
Women aged 65 years and over with moderate or severe visual impairment
outnumber visually impaired men by three to one.
Type of accommodation
There is some evidence that proportionally more older visually impaired
people (20%) live in residential care than their sighted peers (4%).
5.Eye examinations and cataract waiting lists
Since 1999 eye examinations have been free to those aged 60 years and
over. In any one year between 3.45m and 3.95m people aged 60 years and
over (or around 30% of this age group) do not have a free eye examination.
NHS initiatives to reduce cataract waiting lists have benefited those who have
been identified with unoperated cataract. Consequently, those identified by
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epidemiological studies with untreated cataracts will include those whose
cataract was not known to healthcare professionals or those whose cataract
was known but had either not been referred or had declined referral.
6.Registration
In 2003 there were 370, 561 people registered as sight impaired or severely
sight impaired in England, Wales and Scotland2 about 68% of whom are aged
75 years and over .
Evidence emerging from a major study of people with registerable visual
impairment found at least 6% of those aged 75 years and over on local
authority registers were deceased. The prevalence review estimated that
under-registration was likely to lie between 0% and 20%. Taking into account
these estimates of over and under-registration, there is a close match
between the number of people registered as sight impaired and seriously
sight impaired and the estimated number of people who would qualify for
registration as sight impaired or severely sight impaired. This is further
support for the reliability of the population estimates shown in this report.
2
If Northern Ireland operated a registration system the total for the UK would be about 377,
000.
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1.
Introduction - purpose and scope of the paper
Research evidence and official statistics can provide information to assist in
the estimation of the size of the visually impaired population at different ages.
Summarising the work described in this paper, we estimate that in the UK
population the numbers of visually impaired people aged 65 years and over
lies between about 1, 690, 000 and about 2, 264, 000. There are also up to
30, 000 visually impaired children and around 43, 000 visually impaired adults
of working age. These estimates also mean that about 97% of the visually
impaired population is aged 65 years and over3.
The estimates for older people are based on levels of visual acuity ranging
from mild vision impairment (for example inability to read a car number plate
at 20 metres ) to more severe levels of visual acuity at which people have a
statutory entitlement to social care and low vision services through the
registration systems of England, Wales and Scotland. These estimates also
include those whose sight problems are caused by conditions which can be
rectified for example through routine surgery for cataract or by the
prescription of spectacles but who have not been identified as such or who
have not been given appropriate treatment. The estimates also include those
whose sight loss cannot be rectified because there are currently no or very
limited medical treatments to reverse sight loss due to some conditions (such
as age related macular degeneration). Clearly, the visually impaired
population is not homogenous .
The need for reliable population estimates
The reasons for producing this paper is that reliable estimates of the size of
the visually impaired population are needed if health, social service and
voluntary organisations are to effectively develop visual impairment policies
and to plan their services for visually impaired people. They need to know: the
local and national size of this population; the type and degree of sight
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impairment experienced by those that might use their services, how these
patterns might vary by age, gender and by whether visually impaired people
are living in their own or communal homes. Such evidence is needed if
organisations are to have a reasonable idea about whether their services
reach a sufficient number and type of visually impaired people or whether they
are providing the most appropriate services. Such information is also useful
for private sector companies who might want to estimate the likely size of the
market for one of their services or products. There are also other uses for
these estimates such as for campaigning, media and research work.
With these needs in mind, RNIB commissioned Professor Astrid Fletcher to
review existing estimates of the prevalence of visual impairment in the UK.
Professor Fletcher is a senior epidemiologist at the London School of Hygiene
and Tropical Medicine (LSHTM) who with colleagues from the LSHTM and St
George's Medical School have carried out this work and their review of the
evidence is presented in their report 'The prevalence of visual impairment in
the UK – report for the RNIB'. [1] This report can be downloaded from the
RNIB web-site. The report provides a detailed review of epidemiological
research, relating to the prevalence of visual impairment in the UK population.
Their work has identified for the first time those studies that have produced
the most reliable UK prevalence estimates. It is an excellent piece of work and
one that will serve very well those with an interest in the subject.
This paper is largely a synthesis of Professor Fletcher and colleagues review
and refers to it as 'the prevalence review'. Its primary purpose is to use the
prevalence review to provide estimates of the size of the visually impaired
population in the UK. Professor Fletcher also provided valuable comments on
the drafting of this summary paper. In synthesising the prevalence review, this
paper uses two key terms. The first is 'prevalence estimate' and the second is
'population estimate'. Prevalence estimates are estimates of the proportion
(which are usually given as percentages) in the general population who have
These estimates exclude those aged 60 to 64 years an age group for whom
there are no reliable national estimates. All the estimates in this paper are
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a visual impairment. The prevalence review was concerned exclusively with
prevalence estimates. Population estimates are estimates of the number of
people in that population that have a visual impairment. This paper’s primary
focus are the population estimates that can be derived from the prevalence
estimates.
As mentioned above, visual impairment may be caused by conditions that
spectacles or surgery can easily treat. These conditions are mainly refractive
error or cataracts. For the purpose of this paper, these conditions are referred
to as treatable visual impairment. The second type of visual impairment is
caused by conditions for which there are currently no effective treatments and
which, if they reach specific levels of acuity, can result in registration as sight
impaired or severely sight impaired. These conditions include age related
macular degeneration and glaucoma and for the purpose of this paper this
type of visual impairment is referred to as registerable sight loss.
Section 2 of this paper discusses the means by which one can define and
identify those with vision impairment and estimate the size of this population.
In doing so, section 2 discusses the caveats that need to be taken into
account when referring to the tables in this paper. One of these key messages
is that the prevalence of visual impairment depends very much on what is
meant by 'visual impairment'. In particular prevalence estimates will vary
depending on the levels of visual acuity that are included and excluded in any
estimate and whether one includes or excludes causes of sight loss that can
be treated. An equally important caveat is that a definitive and absolute
estimate of the size of the visually impaired population does not exist as all
estimates are derived from samples of the population and, as with all survey
based findings, they are 'best guesses'. Readers are encouraged to read the
prevalence review and section 2 of this paper to grasp these important
distinctions and qualifications.
rounded to the nearest 1, 000.
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These caveats should not be taken to imply that the estimates in this paper
are unreliable. Far from it. They are based on the very best research that has
been carried out in the field in the UK and include estimates produced by a
Medical Research Council funded study. As the very best available estimates
for the UK, the tables should be treated as the most reliable current guide to
understanding the size of the visually impaired population in the UK.
The two main groups who are least well served by studies and official records
of those with sight problems are children and adults of working age. Section 3
summarises the most reliable - albeit - limited statistics and population
estimates for these groups. Estimates for children given in this section are
based on the administrative and research studies covered in chapter 5 of the
prevalence review. The estimates for adults of working age are covered at the
end of chapter 7 of the prevalence review. Sue Keil (RNIB) provided a great
deal of assistance in drafting this section.
By a very long margin, there is a great deal more data about older people
(aged 65 years and over) than for younger age groups and most of this paper
covers this age group. Section 4 describes the main epidemiological studies
that are the basis of the population estimates in this paper. This section
discusses estimates of the causes of visual impairment in older people. This
section is largely based on figure 4.1 and table 4.2 in chapter 4 of the
prevalence review. Section 5 summarises the overall estimates of visual
impairment in older people in the UK. Section 6 discusses identifying and
treating older people with refractive error and cataracts and estimates the size
of this population. Much of the material in this section is based on Department
of Health and census records and not on the prevalence review. Section 7
covers population estimates for older people with registerable conditions by
age group, levels of visual acuity, gender and whether an older person is
living in their own home or a communal establishment. The estimates in this
section are covered in chapter 3 of the prevalence review and, in particular,
table 3.2 in that chapter.
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There are also administrative sources of information about the size of the
visually impaired population. These are Department of Health counts for
England of those who are registered - to use the new terminology - as sight
impaired and severely sight impaired. Administrative counts are also
produced by the devolved governments of Wales and Scotland but not
Northern Ireland, where no systematic official data is collected. Section 8 of
this paper summarises these administrative counts, comments on their
reliability and compares them to population estimates. Most of this material is
not covered in the prevalence review.
There are no available prevalence - and therefore population - estimates for
those aged 60 to 64 years. There are also clinical tests that can measure
visual field and contrast sensitivity but there are no available prevalence
estimates that use these tests. There is also an almost complete absence of
prevalence estimates to identify whether there are differences by region, or by
ethnic groups4.
The paper concludes by identifying the potential implications that population
estimates have for policy makers, service providers, campaigners and
researchers.
The main body of this paper covers estimates for the UK as a whole.
Appendix 1 provides the estimates for the same categories of vision
impairment but they are broken down by the countries that constitute the UK.
All the key research and epidemiological studies, administrative sources and
the 2001 census tables that form the basis of this paper are shown in the
reference section or are summarised in Appendix 2.
4That
there are likely to be ethnic differences is intimated by one study [2] which found that
the prevalence in all ages of registerable sight loss was about two and half times greater
amongst 'Asian' people (1.21%) than amongst white people (0.49%).
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2.
Defining visual impairment for the purpose of estimating
population size
Introduction
This section explains the various means of defining and estimating the
proportion and number of the population with a visual impairment and, in
particular, the means by which the tables in this report were produced.
Defining visual impairment
The prevalence of visual impairment is traditionally defined and measured by
distance visual acuity tested using a Snellen chart or similar. The World
Health Organisation defines visual impairment on the basis of distance visual
acuity and this is the reporting standard for all internationally comparative
studies on visual impairment. Other clinical measures may be used, such
field of vision and contrast sensitivity, and these provide alternate or additional
information about other visual problems such as peripheral vision or colour
recognition. Instruments that use self-defined accounts of the extent of
difficulty in seeing, provide important information on the limitations or
difficulties experienced by individuals as a result of their visual impairment.
Self-defined accounts of performing specific tasks or self-defined accounts of
well-being are a good way of identifying the impact of sight problems. These
measures may range from the simple use of questions, such as being able to
see a friend across the road or reading newspaper print, to the use of more indepth scales that evaluate the impact of vision problems across a range of
domains of everyday life including physical and social functioning and
psychological well-being. Such instruments are often referred to as visionrelated quality of life measures.
Neither clinical tests nor self-defined accounts are inherently 'better' than the
other. Their relative advantages and disadvantages depend on the use for
which they are needed. An advantage of self-defined accounts is that they
paint a clearer picture of functional ability than clinical measures. But they
cannot be used to judge the physiological nature of sight loss. Neither can
they discriminate between functional ability arising from visual impairment that
20
can be corrected by spectacles or by surgery and visual impairment arising
from conditions which currently cannot be corrected or reversed, such as
glaucoma. The prevalence review also observed that estimates that use selfreported vision loss do not necessarily use valid questions. And because they
often include those with relatively minor visual problems, such estimates can
over-estimate the size of the population. Responses to questions are also
influenced by people's health expectations and their tolerance, beliefs and
attitudes to ill health. As these change over time so too will estimates that use
self-reported instruments. Chapter 6 of the prevalence review discusses the
relationship between responses to such vision related quality of life questions
and the visual acuity of respondents to the effect that visual acuity is only
associated with 20% of the variation in quality of life measures. It concludes
from this that the quality of life scales should not be used as substitute for
visual acuity.
Clinical tests are objective measures of the physiological nature of sight loss
and are not influenced by subjective factors such as the psychological and
social factors that might influence the ways in which those with sight problems
regard their visual impairment. The national studies that have used clinical
tests have used samples that are representative of the general population. A
limitation of clinical tests is that they do not necessarily give sufficient
information about functional ability, that is the tasks and activities that can and
cannot be carried out arising from having a visual impairment or that arise
from the social barriers to those with sight problems.
This paper presents estimates that measure visual impairment in terms of
visual acuity (VA) using a Snellen visual acuity test chart or similar.5 Snellen
scores of visual acuity are scores of the best direct vision that can be obtained
in reading the letters on a Snellen chart over a specified distance.
Visual acuity can be measured in a number of different ways. Visual acuity
can be measured with usual aids if worn, that is contact lenses or glasses
5Snellen
tests are routinely used by optometrists in carrying out eye examinations.
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(known as “presenting vision”) or after full refraction for refractive error (known
as “best corrected visual acuity”). People wearing spectacles may still have
poor acuity, either because they have a different vision problem which is not
helped by spectacles, such as cataracts, or because the spectacles they are
wearing may not be suitable or they may have spectacles but were not
wearing them at the time they were examined. In population surveys full
refraction may not be available and studies may use pinhole correction to try
to remove some of the refractive error (known as "pinhole corrected visual
acuity"). Results may be presented as binocular vision (that is, visual acuity
measured with both eyes open) or as vision in the better eye (each eye
measured separately with the other eye covered). Each table in this report
specifies whether the estimates use presenting acuity or pin hole correction
as the means of defining visual impairment.
The tables in this paper that are about older people sub-divide the visually
impaired population into up to three categories of VA. Two of these categories
are moderate and severe visual impairment. Those in these groups who
have eye conditions such as AMD that are likely to make them eligible for
registration broadly correspond to the categories 'sight impaired' and 'severely
sight impaired' that are now used by the Department of Health for registration
purposes. The statutory definitions of these terms are given in section 7.
Those in the moderate and severe visual impairment groups also include
those with uncorrected refractive error and/or those with treatable cataracts6.
Those with refractive error or untreated cataracts would not qualify for being
registered as sight impaired or severely sight impaired because they have a
treatable cause of vision impairment. But their VA is effectively equivalent to
being sight impaired and severely sight impaired for so long as their
impairment remains untreated. It is for this reason that they are included in
some of the population estimates presented in this paper. These two groups
are referred to in the tables in descending order of the degree of impairment
as:
6
An important qualification to this definition is that in practice that those with VA 6/18 can only
be registered if they also have impaired field of vision. It was not possible to carry out a field
22

Severe visual impairment for those with VA <3/60.

Moderate visual impairment for those with VA 6/18->3/60.
The third category of visual impairment covers those with less severe levels of
vision impairment. These are referred to in this report as those with:

Mild visual impairment if their VA is between <6/12 and 6/18.
For example someone in this category would not be able to recognise a
number plate at a distance of 20 meters as required by the UK's Driver
Vehicle Licencing Agency (DVLA) to pass a driving test.
RNIB ordinarily avoids using these terms as they might imply value
judgements about the nature of visual impairment that can be inappropriate
from the perspective of the visually impaired person. For example, a person
defined as having a ‘mild visual impairment’ might not experience it as mild if
they are no longer able to drive a car or are impeded from doing their work.
But RNIB also recognises that these terms have international usage,
especially in the context of scientific discussions about visual impairment and
do not represent value judgements about the impact of that level of vision
impairment.
One of the key issues identified by the prevalence review that needs to be
understood is the wide variation in the definitions of visual impairment and the
inconsistency in the cut-off points of visual acuity to estimate prevalence. The
prevalence review and this summary should help clarify some of the confusion
that has arisen as a result of this variability and inconsistency. This paper
endorses the recommendation of the prevalence review that consistent
national and international measurement standards should be adopted in
research about prevalence and other aspects of sight loss, as has been
recommended by a WHO Working Group [3]. This paper also endorses the
of vision test for the MRC and NDNS studies which produced most of the estimates on which
23
prevalence review's recommendation that any research report that uses
prevalence or population estimates should make the methods and definitions
used transparent and clear. Submitting any research paper to the peer review
process (or equivalent) is the usual means of ensuring that standards are
maintained in academic research will help achieve this.
Population estimates
It is important to understand that one fixed or absolute estimate of the size of
the visually impaired population does not exist and cannot be found (except in
the unlikely situation that the entire population is measured). The prevalence
rates (given as percentages) or the population sizes (given as numbers)
shown in these tables are all estimates. As with any statistical estimate that
uses a sample of the population, it is not possible to be certain that it is the
same as the true or actual size that will be found were all of the general
population surveyed. That is, we cannot say that there is one single
percentage or number that identifies the UK prevalence rate or population
size for those who are visually impaired. In using the tables in this paper, it is
vital that this point is understood and remembered. Instead, by using the
prevalence rate in the samples studied and the sampling error, we can
calculate the range in which the true population estimate is likely to fall.
To emphasise the need to always be aware that prevalence and population
estimates are never absolute, each cell in tables 2, 3, and 4 have three
numbers. The first is the estimated prevalence rate or a very approximate
population estimate (depending on the table being read) produced by the
sample from which the estimate has been taken and the other two are the
range in which the true prevalence rate or population estimate is likely to fall.
This range is known as the 'confidence interval'. This is the range in which it is
predicted that the true population estimate or true prevalence rate is most
likely to be. For example Table 3 gives the percentage prevalence estimate of
those aged 85 years and over and who are moderately or severely visually
impaired as 26.8% and the confidence interval for this estimate as 25.5% to
this paper is based. The importance of this qualification is discussed in section 7.
24
37.8%. This means that the proportion in the sample with this level of visual
acuity was 26.8% and that the true prevalence of those with these levels of
visual acuity in this age group in the general population is most likely to be
between 25.5% and 37.8%. Table 4 shows that the approximate population of
those in this group is 301, 000 but that the true population estimate is most
likely to be any where between 269, 000 and 339, 000. The tables in section
7 do not give confidence intervals because these were not given in the
published paper from which the estimates were taken. But readers of these
tables must be aware that these too will have confidence intervals and as
such these estimates should not be treated as absolute. It is also worth noting
that the larger the study or survey, the smaller the standard error and hence
the narrower the confidence interval. So larger studies have greater precision
in their estimated confidence intervals. Conversely small studies will have
very wide confidence intervals. This is one of the reasons why we place
greater emphasis on larger studies.
The estimates presented in this paper are based almost entirely on two UK
national studies [4,5]. The first is a Medical Research Council funded survey
of 14, 600 people aged 75 years and over living in the community and which
assessed their health status. The study was carried out by Professor Fletcher
and other colleagues. The data used in the prevalence review is from the
visual impairment component of the survey which was published in 2002. The
second study was of 1, 400 people aged 65 years and over living in their own
or nursing homes carried out as part of the National Diet and Nutrition Study
published in 2000. Dr Chris Bates and Jolieka van der Pols from the MRC
Human Nutrition laboratory in Cambridge kindly gave Professor Fletcher
access to the vision data to produce the summary in the prevalence review
and which forms part of the basis of tables 3 and 4 in this paper. These
studies are referred to in the tables in this paper as 'MRC [4]' and 'NDNS [5]'.
The method used to produce the population estimates in this paper was to
multiply the prevalence estimate for each of the three age groups used in the
tables by the number of people identified by the 2001 census living in the UK
25
in the corresponding age group7. The same method can be used to estimate
country and local population sizes for the same age and VA acuity groups
given in these tables. For example, Table 26 in Appendix 2 shows that the
census for Scotland records that there are 446, 033 people aged 65 - 74
years living in this country. Table 3 shows that the sample estimate for this
age group with VA < 6/18 is 5.6% and that the confidence interval is 3.5 7.6%. Therefore, as Table 15 shows, an approximate estimate of the
population of visually impaired people in Scotland aged 65 to 74 years is
about 25, 000 and that the true population in this group is likely to be between
about 16, 000 and 34, 000.
Country estimates assume, of course, that prevalence does not vary by
country or by local area. But it might be that prevalence varies geographically
depending on factors such as the ethnic and socio-economic profile of the
local population, local eye examination take-up, the nature of local optometric
and ophthalmic provision and ease of access to eye care services between
rural and urban areas. Because of the potential for such variation, country
population estimates should be treated with a great deal of caution.
7
Summary census tables for the UK and the countries that make up the UK are shown in
Appendix 2. The web-page addresses for the 2001 census tables for these countries are
given in footnote 27 in Appendix 2.
26
3. Children and working age adults
Introduction
This section summarises UK population estimates of children who are visually
impaired. Because there are no UK based population estimates for working
age adults, this section draws on a literature review of estimates in other
countries.
Children
The review identified epidemiological studies [6], other surveys [7 - 13] and
administrative data [14, 15] as providing the best available estimates of
prevalence amongst children. These produce population estimates that vary
between 7, 000 and 30, 000 visually impaired children in the UK. An important
reason for this variation is the different ways in which children are defined and
identified as visually impaired. For example:

The lower estimate is from the epidemiological study and used a very
high threshold of visual impairment in children to qualify for inclusion in
the study. This estimate is only of children aged up to 16 years and
classified as having the most severe forms of visual impairment.

Higher estimates are produced where visually impaired children are
defined in terms of meeting local education and social services criteria
for the provision of specialist services or are identified through the use
of self-defined accounts of impairment discussed in section 2 of this
report. Consequently, these studies include children with a broader
spectrum of visual impairment than would have been covered by the
national epidemiological study.

The higher estimates also use different age cut-off points for defining
children. For one study, it is 15 years [7], for four it is 16 years [9, 10,
12, 14], for one it is 18 years [11], for two it is 19 years [8, 15] and for
one it is limited to 11 to 14 year olds [13].
27
As such, these estimates have to be used carefully, with great caution and
with a grasp of the complexity of the means by which they have been made.
The prevalence review concluded that:
“there are no agreed definitions of visual impairment among children…Terms
such as visual impairment and visual disability have been used to mean
different things in different studies and contexts”.
Epidemiological data
The only reliable national epidemiological estimate of prevalence in children
only covers children at the most severe end of the visual acuity spectrum [6].
Children were included only if they were aged up to 16 years and

had corrected visual acuity of worse than 6/60 in the better eye or

were eligible for notification to the national registers of blindness or

were unable to fix or follow a light (but whose acuity could not be
measured formally).
The threshold of 6/60 is close to the threshold of 3/60 required to be eligible to
be registered as seriously sight impaired. The cumulative incidence (similar to
prevalence) reported in this study for children up to the age of 16 years was
5.9 per 10,000 children. This study observed that the characteristics of the
population of children with severe visual impairment or blindness is changing.
This is because:

There has been a reduction in the incidence of preventable disorders such
as congenital cataract.

The decline is linked with improvements in primary prevention, early
detection and medical and surgical management.

There has been an increase in untreatable disorders such as cerebral
visual impairment, heredity retinal dystrophies, optic nerve atrophy and
hypoplasia.

The increase is linked with changing trends in childhood chronic disease
and disability that are themselves linked with increased survival of
28
premature and very low birth weight babies and children with major
anomalies, complex neurological and metabolic diseases and malignant
disease.
The consequences of these changes are that:

Proportionally more children with severe visual impairment and blindness
now have additional – often very complex – disabilities. In one study [6]
77% of children had additional non-ophthalmic disorders or impairments.

Very premature and low birth weight babies are at particular risk of severe
visual impairment and blindness.

A higher than expected proportion of children with additional disabilities
reflects partly the changing nature of the population at risk. It has been
speculated that this proportion may also partly reflect the fact that other
studies which rely on ophthalmic sources alone under-represent the
number of children with additional disabilities.
A comparison of 1958 and 1970 British birth cohorts and the British national
registers for blindness [6] show that:

In the 1958 birth cohort the prevalence of blindness in 10 – 11 year olds
was one per 10,000.

For the 1970 birth cohort this had increased to 4 per 10,000 children aged
between 10 and 11.
Other survey and administrative data
In addition to epidemiological studies, data on childhood visual impairment
and blindness is collected through social surveys such as the 1985 OPCS
disability surveys [7] and RNIB surveys [9, 10] of local education authority
(LEA) visual impairment advisory services. The Department for Education
and Science (DfES) has also recently started to collect statistics on different
special educational need (SEN) groups as part of its Pupil Level Annual
Schools Census in England and Wales [14]. Children can be certified as sight
29
impaired or severely sight impaired but most of those eligible do not become
certified but we do not know the reasons for this.
LEA administrative data from visual impairment advisory services is such that:

Individual services have their own criteria for deciding whether or not a
child with sight difficulties will be included in their caseload. This means
that in some areas the threshold for qualifying as visually impaired will be
lower than in others and this will affect whether they receive support from
a specialist teacher. The Welsh Assembly has observed that
“…In some areas the service for visually impaired children and young
people has included children and young people with a slight reduction
in visual acuity who may only be seen by them twice-yearly or annually.
In other areas, these children and young people would not meet the
descriptors for intervention”. [15]

Specialist teachers are often cautious about using rigid criteria for referrals
because individual children vary so much in terms of their visual
functioning. Two children with the same diagnosis and VA may function
very differently and require quite different levels of specialist support.

LEA visual impairment advisory services vary in the degree to which they
are able to offer support to children with a visual impairment, who have
additional severe and / or complex disabilities and who are being educated
in special schools. Hence there is likely to be a wide variation between
LEAs in reporting the incidence of this group of children.
In spite of these variations in criteria and policies data collected from LEA
advisory services tend to show prevalence at about 20 children per 10,000. [9,
10] However, the prevalence rate reported by the DfES based on the
individual pupil data (PLASC) collected from schools finds 10.5 per 10,000
30
whose primary special educational need is a visual or multi-sensory
impairment. [14]
The discrepancy between LEA and DfES data is that the DfES only includes
children whose primary disability is visual impairment which means that DfES
data is likely to under-represent the size of the population of pupils with a
visual impairment. This is also because there are no clear guidelines about
who should record the pupil’s SEN as part of the data collection process for
PLASC. Consequently unqualified staff are likely to be recording pupil details
and in doing so making subjective judgements about what constitutes the
child’s primary special educational need for children who have more than one.
The prevalence review concludes that for estimates of prevalence for children,
two types of estimate should be used. The first is of children who have "visual
loss sufficiently bad as to mean a child is identified as being in need of special
educational or social services". For an estimate of children who fall into this
category, the review recommends an estimate of 10 - 20 per 10, 000
children. The second type of estimate is of children with "severe visual loss"
aged up to 16 years. The study [6] that produced this used the threshold of
VA worse than 6/60 and estimated prevalence as 5.9 per 10, 000 children.
The population estimates derived from these prevalence estimates are:

Between 12, 000 and 30, 000 children using the higher prevalence
estimates based on broad definitions of visual impairment and age cut-off
points between 15 and 19 years8.

7, 000 children using the lowest prevalence estimate that is based on a
narrow definition of visual impairment with an age cut-off point of 16 years.
8
The lowest population estimate uses the 10 in 10, 000 prevalence rate with the 0 - 15 years
population and the highest population estimate uses the 20 in 10, 000 prevalence rate with
the 0 - 19 years population. Table 13 shows the total UK population size for the 0 - 19 age
group as 14, 768, 622. The tables in the appendix do not have a table for the 0 - 15 or the 0 16 age groups but census records show that there are 11, 792, 512 children aged 0 -15 years
and 12, 553, 193 children aged 0 - 16 years in the UK population.
31
The prevalence review recommends that consistent criteria is needed to
define visual impairment in children and to identify the needs of children with
and without additional disabilities.
Working age adults
There are even fewer UK estimates of prevalence amongst adults of working
age than of prevalence amongst children. Indeed, the prevalence review was
only able to identify a review of epidemiological studies in Western Europe,
North America and Australia [16] as the best estimate of prevalence in the
younger adult age groups and these estimates are shown in Table 1. The VA
ranges used in this table are not the same as those used sections 4 to 7 of
this paper that covers prevalence amongst older people. These tables use the
VA categories of 6/12 to better than 6/18; 6/18 to better than 3/60; and worse
than 3/60. It should be noted that:

There are no estimates of prevalence of VA better than 6/18 in the working
age population.

The range 6/24 to 6/48 in Table 1 is a sub-group of the range 6/18 to
better than 3/60 used in the tables in sections 4 to 7.

The range worse than 6/48 in Table 1 overlaps the ranges of 6/18 to
better than 3/60 and worse than 3/60 in the tables used in section 4 to 7.
This means that a comparison of the prevalenceof visual impairment
amongst those of working age with the prevalence amongst older
people.cannot be made. The VA cut-off points and the age-breaks used in
administrative counts of those of registered and of working age are different
to those used in the studies reported in this paper who are likely to be
registered or registerable. It is difficult to compare these sources.
Nevertheless, the estimated 43, 000 aged 20 to 59 years identified in Table 1
compares well with the 36, 000 registered in England and Scotland aged 16
to 49 years as identified in tables 10 and 11 in section 8 that show
registration counts. The prevalence review concluded that registration data:
32
"provide reasonably accurate estimates of the prevalence of serious
impairment in the younger adult age groups."9
Table 1:
Prevalence and population estimates of visual acuity (Age: 20-59 years)
Source: Nissen [16]
Visual acuity
Percentage prevalence Population estimate
6/24-6/48
0.07
22, 000
<6/48
0.08
25, 000
Section summary
Given that definitions of visual impairment in children vary considerably
between studies and official data, considerable caution and clarity is needed
when using these estimates. There are very large gaps in knowledge about
prevalence and population estimates for those of working age because there
are very few international ones and none for the UK.
9
See page 11 of the prevalence review.
33
34
4.The research basis of prevalence estimates and the causes of visual
impairment in older people
Introduction
Compared with prevalence estimates for children and working age adults,
there is a relative abundance of evidence about prevalence amongst older
people. The population estimates for older people used in this paper are all
based on the visual impairment component of the MRC study [4] completed in
2002 and the visual impairment component of the NDNS study [5] completed
in 2000. This is because these studies are the only ones to:

Use large, representative samples of the UK older population

Use unambiguous and clear definitions of visual impairment

Report response rates and confidence intervals

Have been peer reviewed
In addition the MRC study

Identified the causes of visual impairment

Differentiated between treatable and registerable causes and levels of
visual impairment.
There are no other UK prevalence studies that meet these quality standards10.
This section describes these studies and uses them to provide population
estimates in terms of the causes of visual impairment in older people.
The MRC and NDNS studies
The MRC study reported presenting binocular acuity for VA < 6/12 in those
aged 75 years and over and also measured visual acuity in each eye using
pinhole correction in the same age group but only for those with VA < 6/18..
Causes of vision impairment were investigated only for those with pinhole
corrected VA <6/18 in the better eye. The MRC study included those living in
their own homes or in sheltered or residential accommodation, but excluded
10
There are a number of national and international studies that observe high research
standards but these are limited to studies of specific eye diseases. [17 - 23]
35
people in nursing homes. The NDNS study only used the pinhole test and so
filtered out those with refractive error. Because pinhole correction is relatively
crude it is likely that some people with refractive error were not identified
through the pinhole method. The NDNS study included those aged 65 years
and over, those with VA 6/12 or worse and those living in all private homes
and those in residential, sheltered and nursing homes11.
General estimates of the prevalence of the causes of visual impairment
The cut-off point of VA < 6/18 is largely used for the purpose of the tables in
this paper as the point which approximates to the statutory threshold for
qualifying as registered severely sight impaired or registered sight impaired.
The overall prevalence of all causes of visual impairment in those aged 75
years and over with VA < 6/18 was 12.4%. Based on these data, the UK
population estimate for this group is 546, 00012. About half of them have
cataracts or refractive error and if these are excluded, the prevalence
estimate of those with 'registerable' eye conditions is 6.4% and the population
estimate is 282, 000. A small proportion have both cataracts and some other
registerable cause of vision impairment so are not excluded. The estimated
population of those aged 75 years and over with untreated cataracts and
refractive error with VA < 6/18 is 264, 000.
Estimates of the prevalence of specific causes of visual impairment
Prevalence estimates for the specific causes of sight loss for those aged 75
year age and over are summarised in Table 2. This shows that about 56% of
visual impairment in this age group is accounted for by treatable vision
impairment . The remainder of this population have registerable levels and
types of sight loss.
11
The MRC study did not cover those living in nursing homes but covered those living in the
other types of accommodation.
12 There are 4, 404, 719 people in the UK aged 75 years and over. The total of 546, 000, the
column total for Table 2 (605, 000) and the total of those aged 75 years and over with VA <
6/18 (580, 000) do not correspond. This is partly because some older people have more than
one type of visual impairment, partly because cell totals are rounded to the nearest 1, 000
and partly because the confidence intervals will vary depending on the ways in which
prevalence estimates are presented. This is even more reason to treat population estimates
as indicative rather than as absolute estimates.
36
Table 2:
Causes of visual impairment:
Population estimates of specific eye conditions amongst those aged 75
years and over with uncorrected presenting binocular VA <6/18
Source: MRC [4] & Census 2001
Cause
Percentageof visual
impairment due to
specific causes
(95% CI)
36.2
AMD
(32.9 - 39.5)
31.6
Refractive error
(28.3-34.8)
24.5
Cataract
(21.8-27.4)
7.9
Glaucoma
(6.2-9.6)
2.3
Diabetic eye disease
(1.5-3.1)
0.6
Vascular occlusions
(0.1-1.1)
2.9
Myopic degeneration
(1.9-3.8)
4.7
Other
(3.7-5.7)
Population estimate
(95% CI)
210, 000
(191, 000-229, 000)
183, 000
(164, 000-201, 000)
142, 000
(126, 000-159, 000)
46, 000
(36, 000-56, 000)
13, 000
(9, 000-18, 000)
3, 000
(1, 000-6, 000)
17, 000
(11, 000 - 22, 000)
25, 000
(20, 000-31, 000)
Assumptions should not be made that the same profile of conditions will be
found in other age groups. This is because the prevalence of the causes of
vision impairment will vary by age group. In particular, untreatable conditions
become much more debilitating in later life because the VA of those with
these conditions will deteriorate as they get older. Consequently, there will be
a higher proportion of those with untreatable eye conditions (such as AMD) in
the oldest age groups.
Section summary
The most common causes of sight loss in older people aged 75 years and
over are cataracts and refractive error. AMD is the most common cause of
registerable sight loss in older people. There are proportionally more older
people with correctable sight loss than with registerable sight loss in the 75
37
years and over population and these groups are discussed in more detail in
sections 6 and 7.
38
Section 5: Older people and general estimates
Introduction
This section summarises the overall levels of visual impairment in the older
population based on the MRC and NDNS studies. While the MRC data was
collected between 1995 and 1999 and the NDNS data was collected between
1994 and 1995, there are unlikely to have been large temporal changes since
this period in the prevalence of registerable conditions. As such, the
population estimates in this section for these conditions can reasonably be
assumed to be current. However, we need to be much more cautious when
extrapolating population estimates for treatable conditions from data that is up
to 12 years old, even if these estimates are applied to more recent census
measures of the population. This is because in the period after the MRC and
NDNS data was collected, the UK National Health Service (NHS) has cut
waiting lists for cataract surgery. In this period, there might also have been
changes in the patterns of the treatment of refractive error. This is not to say
that the prevalence of untreated refractive error and cataracts identified 12
years ago has been rectified. For the reasons given in section 6, it is possible
that the same prevalence of treatable visual impairment remains undetected
and therefore untreated. It is just that there is insufficient recent evidence to
verify or quantify this. The tables in this section are for the UK as a whole but
estimates for the countries in the UK are given in Tables 14 to 16.
UK prevalence estimates
Table 3 summarises the prevalence estimate for older people in the UK as a
whole.
39
Table 3:
Summary of UK prevalence estimates:
for visual impairment amongst older people
living in their own homes, residential and sheltered housing13
(by age group and visual acuity)
Sources:
NDNS [5] for those aged 65-74 years14
MRC [4] for those aged 75 years and over
Age group (95% confidence interval)
Visual acuity
(uncorrected
presenting
65-74
75-84
85+
binocular
acuity)
Mild
impairment:
VA <6/12-6/18
10.2
10.2
19.0
(9.1-11.5)
(9.4-11.1)
(18.3-19.8)
Severe and
moderate visual
impairment:
VA <6/18
5.6
(3.5-7.6)
8.5
(7.1-9.8)
26.8
(23.9-29.7)
There is an important qualification to make about Table 3. Prevalence
increases with age and this becomes especially marked in the age groups for
the over 65 years population. This means that we would expect the
prevalence of VA <6/12 - 6/18 in the 65-74 age group to be lower than for the
75-84 age group. But Table 3 gives identical prevalence estimates for these
groups. The reason for the similarity is that they are derived from different
studies with substantially different sized samples. The estimates for the
younger age group shown here is taken from the NDNS study (n=1, 400) and
the older age group estimate is taken from the MRC study (n=14, 600). We do
not have an estimate for the younger age group from the MRC study as the
13The
estimates in the column for those aged 65-74 also includes those living in nursing
homes. This omission in the other columns would make a very small difference to their totals.
14 The NDNS estimates given here are unpublished. Professor Fletcher was given access to
the NDNS data and the estimates and CIs in this table were calculated by her specifically for
the prevalence review.
40
study was limited to those aged 75 years and over. For the NDNS study for
the 75-84 year old cell, the estimate was 11.6%.
Table 4 uses the prevalence estimates given in Table 3 to show population
estimates of those who have either permanent or treatable visual impairment
for the UK population. The confidence interval for this population is between
1.6m and 2.2m.
Table 4:
Summary of UK population estimates:
for visual impairment amongst older people
living in their own homes and residential and sheltered housing
(by age group and visual acuity)
Sources:
NDNS [5] for those aged 65-74 years
MRC [4] for those aged 75 years and over
Census15
Age group (95% confidence interval)
Visual acuity
(uncorrected
presenting
65-74
75-84
85+
binocular
acuity)
VA< 6/126/18
Moderate
and severe
visual
impairment:
VA <6/18
All <6/12
15
Row total
503, 000
335, 000
214, 000
1, 052, 000
(450, 000 568,000)
(308, 000 364, 000)
(206, 000 223, 000)
(964, 0001, 155, 000)
276, 000
279, 000
301, 000
856, 000
(173, 000375, 000
(234, 000322,000)
(269, 000339, 000)
(676, 0001, 036, 000
779, 000
614, 000
515, 000
1, 908, 000
(623, 000 943, 000)
(542, 000686, 000)
(475, 000562, 000)
(1, 640, 0002, 191, 000)
Appendix 2 summarises relevant census counts.
41
Table 4 shows that the approximate population estimate is about 1.9m for
those whose visual acuity is <6/12 and covers a wide range of severity from
those who:

Have mild visual impairment (about 1m).

Have treatable visual impairment that if not treated is at a similar level to
those whose visual acuity qualifies them to be registered. For example,
there are 263, 000 aged 75 years and over in this category. 16

Have a permanent visual impairment such as age related macular
degeneration, glaucoma and other conditions that have developed to the
point where those in this group are or probably should be registered that
qualifies them for registration. For example, there are 317, 000 aged 75
years and over in this category.17
There are no studies that provide reliable national estimates of the 60-64 year
old population. Although the estimate is likely to be somewhere between the
prevalence among working age people (0.15%) and the prevalence amongst
the 65-74 age group (15.8%), the range is too wide to have any practical use
or credibility. Alternatively, we might want to use the administrative count of
those registered as sight impaired or seriously sight impaired in this age
group. But such an exercise would produce an estimate that makes a very
marginal difference to the overall population estimates given in Table 4. This
is because the only corresponding age break in Tables 9 and 1018 that show
registration statistics is for those aged 50 to 64 years and shows that 30, 670
people are registered in this age group as sight impaired and seriously sight
impaired. If we were to assume that most of those registered in the 50 to 64
age group are - as is likely - towards the older end of this group, this would
make a very small difference to the total population estimates given in Table
4. This would be the case even if we made an adjustment to include those
from Wales and Northern Ireland. The value of Table 4 is not substantially
16
See Table 2 for prevalence estimates
Some of these will also have cataracts or refractive error.
18 These age breaks are the ones used in official statistics.
17
42
diminished by the absence of an estimate of visual impairment in people
aged 60 to 64 years.
It is also inevitable that prevalence rates and population size will change over
time. The factors that are likely to increase the rates and sizes presented in
this paper include:

The ageing of the UK population.

The likely increase in those with diabetic retinopathy arising from
increases in the prevalence of obesity and diabetes.
Factors that are likely to reduce prevalence rates and population size include:

Improving the take-up of eye examinations by older people if this results in
the increased identification and treatment of refractive error and
cataracts.19

Developments in biomedical research that widen the availability of
treatment options and improved prognosis for those with conditions such
as age related macular degeneration.

Improvements in the health status of successive generations of older
people [24]
For example, if we assume that prevalence does not change and that there
are no improvements in treatment, a paper quoted in the prevalence review
[25] estimates that by 2020 there will be 11% more people in the UK
population with visually impairing (<6/18) age related macular degeneration.
Section summary
The overall population of visually impaired people aged 65 years and over
with VA < 6/12 is between 1.6m and 2.2m. About 55% have mild VA levels
and of the remaining 45%, some will have treatable conditions and some are
19
The relationship between the take-up of eye examinations and the prevalence of refractive
error and cataracts is discussed in section 6.
43
registered or will be eligible for registration. Factors such as the ageing of the
UK population will increase the size of this population and factors such as
improvements in the take-up and availability of treatment options will reduce
the size. It is not possible to reliably predict the combined effect of such
factors.
44
6.Older people and the screening, treatment and estimates of those with
treatable visual impairment
Introduction
Regular and free eye examinations of older people by optometrists are a
useful method of detecting eye disease in this age group. Such examinations
can readily identify sight loss that can be corrected by the prescription of
lenses. Those with cataract and eye conditions such as age related macular
degeneration and glaucoma, are referred by the optometrist to the local eye
hospital for treatment. In some cases, such as for diabetic retinopathy, early
detection and treatment can enable the deterioration in sight to be slowed
down. This section focuses on the screening, treatment and population of
treatable vision impairment in older people.
Access to free eye examinations
Through an amendment to the Opticians Act (1989) eye examinations have
been free in the UK since 1999 for all those aged 60 years and over. Those
aged 60 - 69 years are entitled to a free examination every two years and
those aged 70 years and over are entitled to one annually. A high take-up of
eye examinations amongst these age groups is important to ensure that vision
problems are identified. However data presented below suggests that take-up
is low.
Census data shows that there are about 5.5m people aged over 60 – 69 years
in the UK. On average half of these (2.75m) are entitled to a free eye
examination in any given year, while the other half should have the
examination in the subsequent year. Census data also shows there are about
6.7m aged 70 years and over and all of these are entitled to an eye
examination every year. Thus, there should be about 9.45m free eye
examinations every year. But government data [25, 26] shows that around
5.5m to 6m free eye examinations a year are given to those aged over 60
years. Therefore, we estimate that in any one year between 3.45m and
3.95m of those aged over 60 years (or between 27% and 31% of this age
45
group) do not have the free eye examinations to which they are entitled at the
recommended frequency.
Before 1999 about half of all eye examinations given in each year to people
aged over 60 were paid for by the NHS. After the re-introduction of free eye
examinations, the NHS paid for virtually all of these examinations and
subsequently about an additional 1.0m people aged over 60 years have eye
examinations each year. That is, about an additional 20% of eligible older
people have received a free eye examination in each year since 1999.
Although the total number of free eye examinations given in each year
increased from around 2.5m before the re-introduction of free examinations to
around 5.5m-6.0m after it, we can infer that most of this increase is accounted
for by the 2.5m that had been paying for their examination before 1999 not
having to do so any longer.
There is insufficient evidence to estimate how many and for how long older
people go without a free eye examination. A forthcoming paper [27] has
identified the potential reasons for older people not having regular free eye
examinations as:

Explicit barriers where there is not an obvious or apparent need such as
noticing that sight has deteriorated; a belief that examinations are not
necessary; or that the care of a spouse constrains the opportunity to have
an examination.

Latent barriers related to the nature of personal experience of sight loss;
attitudes to eye health; knowledge of eye conditions and the causes of
sight loss; awareness of the impact of sight loss and knowledge about its
prevention.

Systemic barriers arising from older people’s perceptions of the eye
examination process, such as their understanding of the role of
optometrists and the costs of spectacles.

Barriers related to ethnicity such as language, faith, religion, gender and
non-medical remedies.
46
Estimates of the population with treatable visual impairment
Evidence of the prevalence of untreated cataracts and refractive error in those
aged over 60 years is a good indicator of the extent to which the impact of the
take-up of free examinations (be they privately paid for or paid for by the
NHS) has on this prevalence. The prevalence review concludes that between
52% and 72% of visual impairment in older people (dependent on the age and
the definition of visual impairment) is accounted for by untreated refractive
error and cataracts.
In the years after the MRC study was carried out there have been successful
NHS initiatives to cut the waiting lists for cataract surgery. But the question
arises as to what extent these initiatives have affected the prevalence of
untreated cataracts. A North London study [28] found that a large proportion
of older people with treatable conditions were not known to eye care
services20 and, as we have seen, up to about 4m older people do not have
regular free eye examinations. NHS initiatives to cut cataract waiting lists
would by definition have only benefited those that already had their eye
condition diagnosed and even those that have cataracts diagnosed will not
necessarily chose to have them removed.
Reducing the number of people with untreated cataracts requires
understanding and addressing a complex array of factors about the
identification and referral of those with cataracts and the acceptance by those
with cataracts that they have them or that surgery would be beneficial. A
nested trial of vision screening was carried out by the authors of the
prevalence review [29]. This found that even after patients with eye problems
requiring treatment or referral had been identified by a health screen carried
out by a practice nurse, this did not necessarily result in improved visual
acuity. In other words, the prevalence of visual impairment in older people
The estimate was 80% but because the study extended to those with VA < 6/9 . [ASTRID IS
THIS THE CASE?] this estimate over states the lack of access to eye care services by older
people and again the North London study can only be used for indicative purposes. YES but I
would be inclined to just drop this footnote
20
47
will not necessarily decline even if eye examination take-up is improved if
other barriers are not also addressed.
The balance of factors suggests that the 24.5% prevalence of untreated
cataracts identified by the MRC study might not have substantially changed
irrespective of cuts in waiting lists. However, there is no evidence to estimate
current prevalence.
Section summary
It is evident that an unacceptably large number of older people do not take up
their entitlement to regular free eye tests but rectifying this will not necessarily
reduce the prevalence of visual impairment. More research is needed to
identify whether there are subgroups in the population with very low
attendance over several years and the barriers to eye examinations.
Attendance for an eye test and referral for treatment or further investigations
is also no guarantee of acceptance by patients and their families of possible
treatment. Research is needed to identify the most effective means of
reducing the prevalence of treatable conditions.
48
7. Older people, moderate to severe visual impairment, gender and
accomodation
Introduction
This section provides tables of prevalence and population estimates of those
with moderate to severe vision impairment in terms of age group, gender and
the type of accommodation in which people live. Because the NDNS study
covered a younger age group than the MRC study and also included people
living in nursing homes, the tables in this section draw exclusively on the
NDNS study.21 Those with a visual impairment that require attention and
treatment by a hospital based ophthalmologist are a qualitatively different
group to those who have refractive error and can be helped by a high street
optometrist. Refractive error can easily be identified by high street
optometrists through an eye examination and - unlike other causes of visual
impairment - it can be corrected by spectacles, does not require surgery and
does not lead to registration.22 For these additional reasons, the tables in this
section do not cover those with refractive error. This is not to under-estimate
the adverse impact on daily life of refractive error. This is an especially
important group of visually impaired people especially for those with VA <
6/18 which the MRC study found accounted for nearly a third of all visual
impairment in those aged 75 years and over.23
Gender
Table 5 shows that there are proportionally more women than men in each of
the age groups with VA < 6/18.24 Because there are also more women than
men in the general population in these age groups (see table 23 in the
appendix), Table 6 shows that the combined effect of this and the higher
21
All the tables in this section are derived from table 3.2 of the prevalence review.
Pinhole correction is not a wholly satisfactory substitute for full refraction because some
people are unable to do the test. Consequently it is likely that surveys that use the pinhole
test will not have excluded all those with refractive error.
23 For the reasons given in the last paragraph of section 5, this proportion will be higher
amongst visually impaired people aged 65 to 74 years.
24 Tables by gender for those with VA 6/12->6/18 are not given as the original NDNS paper
[ASTRID - WHICH IS IT?] does not gives estimates for this group. For the same reason,
confidence intervals are not given in these tables.
22
49
prevalence rates in women produces population estimates with substantial
differences between men and women. We do not know enough about the
reasons for differences in prevalence rates between men and women and
more research is needed to explain this.
Table 5:
UK prevalence estimate of pinhole corrected VA < 6/18 for those living in
their own homes, sheltered housing and residential and nursing homes
(By gender, and age group)
Source: NDNS [5]
Age group (years)
65-74
75-84
85+
Men
1.8
9.9
28.9
Women
4.7
13.6
40.0
Table 6: UK population estimate of pinhole corrected VA < 6/18 for those
living in their own homes, sheltered housing and residential and nursing
homes
(By gender, and age group)
Source: NDNS [5] and Census 2001
Age group (years)
Men
65-74
75-84
85+
TOTAL
41, 000
129, 000
90, 000
260, 000
124, 000
269, 000
326, 000
719, 000
149, 000
398, 000
416, 000
979, 00025
Women
25
For the reasons given in footnote 6, this total does not match the corresponding estimate of
856, 000 in Table 1. More importantly, 979, 000 is within the relevant confidence interval in
that table.
50
Type of accommodation
The NDNS data suggests that older visually impaired people might be more
likely to be found in residential care (20%) than their sighted peers (4%).
However, the definitions used are such that we can not be certain about this
and further research is needed to explore the extent to which this is the case.
Section summary
Women have higher prevalence rates of vision impairment than men which
may reflect factors such as eye care utilisation or differences in underlying
aetiology. It might be that visual impairment is a significant factor in
determining whether an older person lives in institutional care but research is
needed to establish the extent to which this is the case and the role played by
other impairments.
51
8.Administrative counts of those registered - their reliability and
comparison with population estimates
Introduction
Local authority social service departments in England, Wales and Scotland
are responsible for maintaining registers of their residents who have been
certified as sight impaired or severely sight impaired. This section defines
these terms, summarises these administrative counts and discusses their
reliability.
Definitions
Registration as blind or partially sighted have been the terms used in the UK
for a very long time to identify those people whose sight problems meet
criteria that effectively act as a gateway to social and other services. The
Department of Health has recently changed this terminology.26

The term 'sight impaired' has replaced the term 'partial sight'.

The term 'blind' has been replaced by the term 'severely sight impaired'.
There are no precise statutory definitions for the terms severely sight impaired
and sight impaired. The National Assistance Act 1948 states that a person
can be certified as severely sight impaired if they are “so blind as to be as to
be unable to perform any work for which eye sight is essential” (National
Assistance Act Section 64(1)). The test is whether a person cannot do any
work for which eyesight is essential, not just his or her normal job or one
particular job. Most people who have best corrected visual acuity below 3/60
will qualify as severely sight impaired. The Department of Health guidelines
are that a person can be certified as sight impaired if they are:
26
The new terminology and its definitions can be found at:
http://www.dh.gov.uk/assetRoot/04/11/86/66/04118666.pdf. This report has used the new
terminology even where the sources of the data presented has used the previous
terminology.
52
‘substantially and permanently handicapped by defective vision caused
by congenital defect or illness or injury’.
As a general rule, those who will be eligible to be certified as sight impaired
will include those who have:

VA of 6/1200 to 6/60 with full field.

VA up to 6/24 with moderate contraction of the field, opacities in media or
aphakia.

VA 6/18 or better if they have a gross defect, for example hemianopia, or if
there is a marked contraction of the visual field, for example in retinitis
pigmentosa or glaucoma.
The assessment of vision and the decision to certify are the responsibility of
hospital based ophthalmologists. Those certified as sight impaired and
severely sight impaired are usually referred to the patient's local authority
social services department and are placed on the local authorities register of
those sight impaired and severely sight impaired. The expectation is that
those on the local authority register should then have their social care needs
assessed and should be given the social services and adaptations to meet
these needs. As such, administrative counts of those registered are a
potentially useful means of identifying local and national need for services.
Local authority counts of those registered
Tables 9 and 10 and the subsequent paragraph summarise the counts (or
estimates of them) by local authority social service departments of those who
are registered as sight impaired and severely sight impaired in England,
Wales and Scotland.27
27
More detailed tables for each of the countries are produced by the government
departments with responsibility for the statistics in the respective countries. The web
addresses for these counts are: England:
(http://www.doh.gov.uk/public/blindpartiallysighted03tables.xls), Scotland:
(http://www.scotland.gov.uk/stats/bulletins/00292-00.asp) and Wales:
(http://www.dataunitwales.gov.uk/Documents/Data_Set/PSS/2004_2005/lgd01045_ssda900_
1_2004_05_v1_bi.xls).
53
Table: 9
England (2003):
Local authority counts of those registered as sight impaired and severely sight
impaired
(by age group)
Age group
0-4
5-17
18-49
50-64
65-74
75+
Total
585
4230
15, 315
12, 935
16, 640
105, 525
155, 230
725
3, 230
17, 090
14, 520
15, 460
105, 655
156, 675
1,310
7,460
32,405
27,455
32,100
211,180
311,905
Sight
impaired
Severely
sight
impaired
TOTAL
Table: 10
Scotland (2003):
Local authority counts of those registered as sight impaired and
severely sight impaired
(by age group)
Age group
0-4
5 - 15
16-29
30-49
50-64
65-74
75+
TOTAL
45
364
470
1, 063
1, 276
1, 755
9, 470
14, 443
Severely
sight
impaired
93
332
356
1, 890
1, 989
2, 364
16, 343
23, 557
TOTAL
138
696
826
2, 953
3, 215
4, 119
25, 813
38, 000
Sight
impaired
A similar table to tables 9 or 10 is not provided for Wales as the Local
Government Data Unit for Wales does not collect information about the age of
those on the registers. This unit produces aggregate tables that show that the
total number of those registered as severely sight impaired in Wales in 2005
was 9, 905 and the count of those registered as sight impaired was 10, 751.
Equivalent statistics are not produced by health or social service
54
organisations in Northern Ireland as a registration system does not operate
there.
Tables 3 and 4 that show that about half of the registered population in
England are registered as severely sight impaired (or as ‘blind’ using the
earlier terminology) while nearly two thirds of the Scottish registered
population are registered as severely sight impaired. It is not clear whether
these differences are part of a trend. If they are, an explanation is required.
Under and over registration
There is evidence that the registers over and under count those who are
registered. Evidence for over counting comes from the Visual Impairment
Centre for Teaching and Research (VICTAR) at Birmingham University who
are carrying out the Network 1000 project. This is a survey of people who are
on the local authority registers for sight impairment. The recruitment process
gave the research team an insight into the accuracy of the registers. They
sent recruitment packs to invite a large sample from those registered with 20
social services departments in England, Wales and Scotland to take part in
the study. At the recruitment stage of the sampling process, about 2% of
those aged 65-74 years and 6% of those aged 75 years and over were
reported as deceased. The overall recruitment rate for the younger age group
was 23% and it was 9% for the older group. It is likely that the higher nonresponse in the 75 years and over group arose because more of them were
deceased. VICTAR’s 6% estimate for those aged 75 years and over and who
were deceased may be conservative.
It is likely that some people in the community would qualify for registration but
have not been identified by health and social services as such and so are not
registered. The prevalence review's estimate of under-registration is between
0% and 20%. The prevalence review also reports two studies of age related
macular degeneration [31, 32] that inferred that under registration of AMD was
probably not substantial.
55
Comparing administrative counts and population estimates
There is good evidence that enables a comparison to be made of the relative
reliability of administrative counts and population estimates. This can be done
by estimating the number of people aged 75 years and over on the registers
for all of the UK, estimating the likely under and over counting on the registers
and comparing this with estimates of the population in this age group with VA
< 6/18 due to registerable or potentially registerable conditions.
If we assume that the same proportion of the English and Scottish registers
who are aged 75 years and over (68%) is the same as for Wales, the estimate
for those registered as sight impaired and severely sight impaired and aged
75 and over in Wales is 14, 000. Estimating those registerable in Northern
Ireland requires the assumption that if there was a registration system in
Northern Ireland those on it aged 75 years expressed as a percentage of all
those aged 75 years and over living in Northern Ireland is the same as for
England, Wales and Scotland.28 If so, we would expect to find about 6, 000
registered aged 75 years and over in Northern Ireland. Thus, the total
estimated number of people aged 75 years and over on local authority
registers in the UK should be about 257, 000. If we also assume 20% underregistration and 6% over-registration, the combined effect of this maximum
possible under-registration and minimum possible over-registration would add
about 36, 000 people aged 75 years and over to the registers. Thus, the
maximum29 possible estimate of all those who are aged 75 years and over in
the UK, who are alive, who are registered or should be registered is 293, 000.
Table 2 in section 4 gave the approximate population estimate of 298, 000
aged 75 years and over with VA < 6/18 caused by eye conditions that are
registerable. The confidence interval for this estimate is 274, 500 to 337, 000.
There is therefore a remarkably close match between:
28
There are about 251, 000 people aged 75 years and over on the registers of England,
Scotland and Wales. The total population in these countries in this age group is about 4, 305,
000. Consequently, the assumed percentage for Northern Ireland is 6%.
29 The estimate is a maximum because it is assuming the lowest possible level of over
registration and the highest possible level of under registration. The likelihood is that the
proportion who are deceased is higher and that under-registration is lower.
56

the maximum possible estimate of all those who are aged 75 years and
over in the UK, who are alive, who are registered or should be registered
(293, 000)

the approximate population estimate of those in this age group with VA <
6/18 (298, 000)
This match adds considerable credibility to the population estimates of those
aged 75 years with VA < 6/18.
We should also point out that the confidence intervals show that the true
population of those in this group is most likely to lie between 274, 500 to 337,
000..
Section summary
The registers cannot be used as a precise measure of the size of the visually
impaired population because of the evidence that the registers:

Over-count because they include people who are deceased.

Under-count because there are some people who are eligible but who are
not registered.
Because we do not have precise estimates of the degree of over and under
counting, we cannot measure the degree of inaccuracy of the registers. As
such, the registers should be treated with caution if using them to measure
the local and national populations of sight impaired and severely sight
impaired people. It is possible that there are proportionally more older people
registered as severely sight impaired than in Scotland than in England
although this apparent difference requires further investigation. A
comparison of prevalence estimates and the number who are registered that
is adjusted for over and under-registration shows that there is a very close
correspondence between the two sources and this considerably strengthens
the credibility of the population estimates given in this paper.
57
58
10.Summary and conclusions
Reliable estimates of the size of the visually impaired population are needed
to inform the work of public, voluntary and private sector organisations. This
paper has summarised these estimates based on a review of prevalence
estimates by Professor Astrid Fletcher, from the London School of Hygiene
and Tropical Medicine, and colleagues. The estimates produced in this paper
should be treated as the most reliable current guide to understanding the size
of the visually impaired population.
We have seen that:

The evidence about prevalence is inconsistent or very limited for children
and working age adults. The number of visually impaired children is about
7, 000 if we use a very narrow definition of visual impairment but it might
be up to 30, 000 if we include any child who needs special education or
social services because of their visual impairment. To rectify this
imprecision, consistent criteria is needed to define visual impairment in
children and such criteria is also needed to identify the needs of children
with and without additional disabilities.

The best available population estimate for working age adults is 43, 000,
although this is not based on a UK study. Research is needed to estimate
the prevalence of visual impairment in working age adults in the UK.

There are between about 1.6m and 2.2m older people aged 65 years and
over in the UK with visual acuity ranging from mild levels to serious and
potentially registerable eye conditions.

The estimated proportion of the visually impaired population that is aged
65 years and over is 97%.
We have also seen that the visually impaired population aged 65 years and
over is not homogenous. For example:
59

About half of this population fall into the category of mild vision impairment
(6/12 -6/18).

The other half have a level moderate to severe visual impairment of visual
acuity.

Of those with moderate to severe visual impairment, about half of them
have cataracts or refractive error. The remaining half have eye conditions
likely to be eligible for registration.

We estimate that between 252, 000 and 343, 000 people aged 75 years
and over in the UK have levels of visual acuity due to potentially
registerable conditions.

Demographic changes alone mean that by 2020 there will be between 20,
000 to 24, 000 more people aged 75 years and over with age related
macular degeneration.
We have seen that administrative counts of sight impaired or seriously sight
impaired older people are not necessarily a reliable measure of the size of this
population because of factors that over and under count the size of this group.
Using official statistics, the best estimate that we can make of the UK
population of those aged 75 years and over who are registered, registerable
and alive is 293, 000. This is broadly consistent with population estimates for
the same age group with VA < 6/18 and adds to our confidence in the
reliability of the population estimates.
It is likely that many of those identified with untreated cataracts in the
prevalence studies will not have benefited from recent initiatives to cut
cataract surgery waiting time. And there is no reason to suppose that the
proportion of older people in the population with untreated refractive error will
have been diagnosed and treated. The size of this population is likely to be
linked to there being up to about 4m older people who do not have the regular
free eye examinations to which they are entitled. We know some of the
factors that influence this low take-up but we do not have data that quantifies
their relative importance.
60
There are important gaps in our knowledge about population sizes. In
particular, we do not have reliable UK estimates for:

The population of working age and of those aged 60 to 64 years.

The socio-demographic characteristics of those with sight loss, especially
in terms of type of accommodation and ethnicity.

Evidence about whether there are regional and country differences in
prevalence.

Visual impairment measured in terms of field of vision and contrast
sensitivity.

The causes of sight loss in those aged under 75 years.
There is also a need for more precise estimates of those deceased on the
registers and the degree of under-registration.
In spite of these gaps in our knowledge, the estimates presented in this paper
are the very best that are available and they can be used to inform the policy,
service development and service provision work of public, voluntary and
private organisations. The estimates can also be used to inform campaigning,
media and research work about visual impairment. And gaps in knowledge
can be used to inform the research priorities of all organisations and
individuals with an interest in and responsibility for visual impairment.
61
9.References
1.Tate R, Smeeth L, Evans J, Fletcher A, Owen C, Rudnicka A The
prevalence of visual impairment in the UK – Report to the RNIB 2005.
2. Hayward L M, Burden ML et al (2002) What is the prevalence of visual
impairment in the general and diabetic populations: are there ethnic and
gender differences?" Diabetic Med 19: 27-34
3.Consultation on development of standards for characterization of vision loss
and visual functioning, in WHO/PBL/03.91. 4-5 September 2003, World
Health Organization Prevention of Blindness & Deafness: Geneva.
4.Evans J, Fletcher AE, Wormald R, Ng ESW, Stirling S, Smeeth L, Nunes
M, Breeze E, Bulpitt CJ, Jones D, Tulloch A., Prevalence of visual
impairment in people aged 75 years and above in Britain: results from the
MRC Trial of assessment and management of older people in the community.
Br J Ophthalmology 2002;86: 795-800.
5.van der Pols JC, Bates C, McGraw PV, Thompson JR, Reacher M,
Prentice A, Finch S, Visual acuity measurements in a national sample of
British elderly people. Br J Ophthalmol 2000; 84: 165-170.
6. Rahi JS, Cable N. Severe visual impairment and blindness in children in the
UK Lancet 2003; 362: 1359-65.
7.Bone M, Meltzer H, The prevalence of disability among children, OPCS
surveys of disability in great Britain Technical Report 3. 1989, Office of
Population Censuses and Surveys: London HMSO.
8.Walker E, Tobin M, McKennel A, Blind and partially sighted children in
Britain: The RNIB survey. Technical report RNIB & OPCS. 1985: London
HMSO
9.Clunies-Ross L Where have all the children gone? An analysis of new
statistical data on visual impairment amongst children in England, Scotland
and Wales. British Journal of Visual Impairment 1997; 15: 48-53.
10.Keil, S., Survey of educational provision for blind and partially sighted
children in England, Scotland and Wales in 2002. British Journal of Visual
Impairment 2003; 21: 93-97.
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11.Flanagan, NM, Jackson AJ, Hill AE Visual impairment in children: insights
from a community-based survey. Child Care, Health and Development 2003;
29: 493-499
12.Rogers M Vision Impairment in Liverpool: prevalence and morbidity. Arch
Dis Child 1996; 29: 299-303
13.Crofts BJ, King R, Johnson A. The contribution to low birth weight to
severe vision loss in a geographically defined population. Br J Ophthalmol
1998; 82: 9 -13
14.Pupil characteristics and class sizes in maintained schools in England.
2004, Department for Education and Skills.
15.Welsh Assembly…
16. Nissen KR, Sjolie AK, Jensen H, Borch-Johnsen K, Rosenberg T, The
prevalence and 6incidence of visual impairment in people of age 20-59 years
in industrialized countries: A review. Ophthalmic Epidemiol 2003; 10: 279291.
17.Coffey, M., A. Reidy, et al. (1993). "Prevalence of glaucoma in the west of
Ireland." Br J Ophthalmol 77(1): 17-21.
18.Friedman, D. S., M. R. Wilson, et al. (2004). "An evidence-based
assessment of risk factors for the progression of ocular hypertension and
glaucoma." Am J Ophthalmol 138(3 Suppl): S19-31.
19.Friedman, D. S., R. C. Wolfs, et al. (2004). "Prevalence of open-angle
glaucoma among adults in the United States." Arch Ophthalmol 122(4): 532-8.
20.Kempen, J. H., P. Mitchell, et al. (2004). "The prevalence of refractive
errors among adults in the United States, Western Europe, and Australia."
Arch Ophthalmol 122(4): 495-505.
21.Kempen, J. H., B. J. O'Colmain, et al. (2004). "The prevalence of diabetic
retinopathy among adults in the United States." Arch Ophthalmol 122(4): 552
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22.Congdon, N., B. O'Colmain, et al. (2004). "Causes and prevalence of
visual impairment among adults in the United States." Arch Ophthalmol
122(4): 477-85.
23.Congdon, N., J. R. Vingerling, et al. (2004). "Prevalence of cataract and
pseudophakia/aphakia among adults in the United States." Arch Ophthalmol
122(4): 487-94.
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24. Andrews GR (2001) ‘Promoting health and function in an ageing
population’ British Medical Journal 322 728-729
25.Increased AMD popn
25. Department of Health (2001) ‘Sight tests volume and workforce survey
2000-01 – optometrists’
26.Department of Health (2004) ‘Sight tests volume and workforce survey
2003-04’ – optometrists and ophthalmic medical practitioners’
27. Charles N, Lightstone N, Odedra N and Hogg A (Fortcoming) Identifying
the barriers to the take-up of free eye examinations by older people in the UK
28. Reidy A, Minassian DC, Vafidis G, Joseph J, Farrow S, Wu J, Desai P,
Connolly A, Prevalence of serious eye disease and visual impairment in a
north London population: population based, cross sectional study. BMJ 1998;
316: 1643-6.
29.Smeeth L, Fletcher AE, Hanciles S, Evans J, Wormold R, Screening older
people for impaired vision in primary care: a cluster randomised trial within the
MRC trial of the assessment and management of older people in the
community. BMJ 2003; 1027-1031.
30.Macdonald AJD, Carpenter GI, Box O, Roberts A, Sahu S, Dementia and
uise of psychotropic medication in non-‘Elderly Mentally Inform’ nursing
homes in South East England. Age and Ageing 2002; 31: 58-64
31.Owen CG, Fletcher AE, Donoghue M, Rudnicka AR; How big is the burden
of visual loss caused by age-related macular degeneration in the UK? Br J
Ophthalmology, 2003; 87: 312-317
32.Evans JE, Fletcher AE, Wormald RPL Ag-related macular degeneration
causing visual impairment in people aged 75 years and above in Britain: an
add-on study the the Medical Research Council Trial of assessment and
management olf older people in the community. Ophthalmology 2004; 111:
513-517
64
65
Appendix 1: Population estimates for England, Wales, Scotland and
Northern Ireland
The main body of the report provides estimates of the size of the UK
population of children, working age adults and older people who have a visual
impairment. This appendix provides the same estimates but for the four
countries that constitute the UK. The tables assume that the prevalence
estimates for the UK as a whole are the same within each country. The total
of the population estimates of the countries will not necessarily equal the UK
totals given in the moan body of the text. This is due to rounding.
Because the census reports conflate the population sizes for England and
Wales, these tables also conflate estimates for England and Wales although it
is hoped that in due course that the tables will show estimates for England
and Wales separately.
Table 11:
Population estimates for visually impaired children
(by nature of sight loss and country)
Visual acuity
VA < 6/60
(aged up to 16
years)
Child in need of
special
education and
social services
(aged up to 15
years)
Child in need of
special
education and
social services
(aged up to 19
years)
England &
Wales
Scotland
Northern Ireland
8, 000
700
300
10, 000
1, 000
400
26, 000
2, 000
1, 000
66
Table 12:
Population estimates of visual impairment in adults aged 20-59 years
(by visual acuity and country)
Visual acuity
England &
Wales
Scotland
Northern Ireland
6/24-6/48
20, 000
2,000
600
<6/48
23, 000
2, 000
700
67
Table 13:
Population estimates of specific eye conditions amongst those aged 75 years and
over with uncorrected presenting binocular VA <6/18
(by cause of sight loss, country30 and 95% confidence interval)
Source: MRC [4]
Cause
England & Wales
Scotland
Northern Ireland
AMD
188, 000
(171, 000 205, 000)
17, 000
(15, 000 19, 000)
4, 000
Refractive error
164, 000
(147, 000 181, 000)
15, 000
(13, 000 16, 000)
3, 000
Cataract
127, 000
(113, 000 142, 000)
12, 000
(10, 000
- 13, 000)
3, 000
Glaucoma
41, 000
(32, 000 50, 000)
4, 000
(3, 000 5, 000)
1, 000
Diabetic eye
disease
12, 000
(8, 000 16, 000)
1, 000
(1, 000 2, 000)
200
Myopic
degeneration
15, 000
(10, 00020, 000)
1, 000
(1, 000 2, 000)
300
Other31
28, 000
(20, 000 -
2, 000
2, 000 -
600
30
The base for each estimate by country is the total estimated population with any visual
impairment < 6/18 in those aged 75 years or over as shown in tables 25, 26 and 27: England
and Wales = 520, 000, Scotland = 47, 000, Northern Ireland = 11, 000. The confidence
intervals are not shown for Northern Ireland because rounding the confidence intervals to the
nearest thousand produces estimates that are the same as the sample estimate. Where
rounding in Northern Ireland to the nearest 1, 000 would produce an estimate of zero, the
estimate is given to the nearest 100.
31 Includes those with vascular occlusions.
68
35, 000)
3,000)
Table 14:
England and Wales population estimates:
for all causes of visual impairment amongst older people
(by age group, visual acuity and 95% confidence interval)
Sources:
NDNS [2] for those aged 65-74 years (2002)
MRC [1] for those aged 75 years and over (2000)
Age group
Visual acuity
(uncorrected
presenting
65-74
75-84
binocular
activity)
85+
Mild visual
impairment:
VA <6/12-6/18
445, 000
(397, 000 502, 000)
299, 000
(276, 000 326, 000)
192, 000
(185, 000 200, 000)
Moderate and
severe visual
impairment:
VA <6/18
245, 000
153, 000 332, 000)
249, 000
(208, 000 287, 000)
271, 000
242, 000 301, 000)
TOTAL: 765, 000 (603, 000 – 920, 000)
69
Table 15:
Scotland population estimates:
for all causes of visual impairment amongst older people
(by age group, visual acuity and 95% confidence interval)
Sources:
NDNS [2] for those aged 65-74 years (2002)
MRC [1] for those aged 75 years and over (2000)
Age group
Visual acuity
(uncorrected
presenting
65-74
75-84
binocular
activity)
85+
Mild visual
impairment:
VA < 6/12-6/18
45, 000
(41, 000 51, 000)
28, 000
(25, 000 30, 000)
17, 000
(16, 000 18, 000)
Moderate and
severe visual
impairment:
VA <6/18
25, 000
(16, 000 34, 000)
23, 000
(19, 000 27, 000)
24, 000
(21, 000 26, 000)
TOTAL: 72, 000 (56, 000 – 87, 000)
70
Table 16:
Northern Ireland population estimates:
for all causes of visual impairment amongst older people
(by age group, visual acuity and 95% confidence interval)
Sources:
NDNS [2] for those aged 65-74 years (2002)
MRC [1] for those aged 75 years and over (2000)
Age group
Visual acuity
(uncorrected
presenting
65-74
75-84
binocular
activity)
85+
Mild visual
impairment:
VA< 6/12-6/18
13, 000
(11, 000 14, 000)
6, 000
(6, 000 7, 000)
4, 000
(4, 000 5,000)
Moderate and
severe visual
impairment:
VA <6/18
7, 000
(4, 000 9, 000)
5, 000
(4, 000 6, 000)
6, 000
(6, 000 7, 000)
TOTAL: 18, 000 (14, 000 – 22, 000)
71
Table 17:
England and Wales population estimates VA < 6/18
(by gender, age group and for all causes except refractive error)
Source: NDNS [5]
Age group (years)
65-74
75-84
85+
Men
37, 000
116, 000
81, 000
Women
109, 000
240, 000
293, 000
TOTAL
234, 000
642, 000
Table 18:
Scotland population estimates VA < 6/18
(by gender, age group and for all causes except refractive error)
Source: NDNS [5]
Age group (years)
65-74
75-84
85+
TOTAL
21, 000
Men
4, 000
10, 000
7, 000
Women
12, 000
23, 000
26, 000
61, 000
Table 19:
Northern Ireland population estimates VA < 6/18
(by gender, age group and for all causes except refractive error)
Source: NDNS [5]
Age group (years)
65-74
75-84
85+
Men
1, 000
3, 000
2, 000
Women
3, 000
6, 000
7, 000
72
TOTAL
6, 000
16, 000
73
Appendix 2: Census measures of the UK population
This annex summarises census measures of the UK population by country,
age, gender and, for whether they are living in a communal establishment or
their own home. The web-sites from which these statistics are taken are given
in the footnote at this bottom of this page.32
Table 20
UK population size: age group by gender
Age group
Male
0-19
7, 558, 508
7, 210, 114
14, 768, 622
20-59
15, 700, 654
16, 098, 834
31, 799, 488
60-64
1, 409, 682
1, 470, 392
2, 880, 074
65-74
2, 300, 538
2, 635, 722
4, 936, 260
75-79
817, 738
1, 149, 350
1, 967, 088
80-84
482, 707
830, 885
1, 313, 592
85-89
226, 520
525, 515
752, 035
83, 490
288, 534
372, 024
90+
TOTAL
28, 579, 837
Female
30, 209, 346
32
TOTAL
58, 789, 183
England/Wales (http://www.statistics.gov.uk/StatBase/Expodata/Spreadsheets/D7547.xls);
Scotland (http://www.scrol.gov.uk/scrol/analyser); Northern Ireland
(http://www.nicensus2001.gov.uk/nica/analyser)
74
Table 21
UK population size for selected age groups
Age group
60 years and over
65 years and over
70 years and over
60-69 years
65-74 years
75-84 years
85+ years
12, 703, 811
9, 340, 999
6, 711, 134
5, 456, 780
4, 936, 260
3, 280, 660
1, 124, 059
Table 22
England and Wales population size: age group by gender
Age group
0-19
20-59
60-64
65-74
75-79
80-84
85-89
90+
TOTAL
Male
6, 676, 649
13, 905, 444
1, 249, 632
2, 045, 001
733, 119
435, 262
205, 152
75, 669
2, 5325, 928
Female
6, 367, 677
14, 234, 620
1, 295,122
2, 322, 031
1, 021, 904
743, 052
471, 526
260, 058
26, 715, 990
Table 23
Scotland population size: age group by gender
Age group
0-19
20-59
60-64
65-74
75-79
80-84
85-89
90+
TOTAL
Male
625, 908
1, 356, 574
124, 651
200, 062
66, 057
36, 355
16, 661
6, 226
2, 432, 494
75
Female
598, 247
1, 414, 649
137, 082
245, 971
99, 466
68, 634
42, 580
22, 888
2, 629, 517
Table 24
Northern Ireland population size: age group by gender
Age group
0-19
20-59
60-64
65-74
75-79
80-84
85-89
90+
TOTAL
Male
255, 951
438, 636
35, 399
55, 475
18, 562
11, 090
4, 707
1, 595
821, 415
Female
244, 190
449, 565
38, 188
67, 720
27, 980
19, 199
11, 409
5, 588
683, 839
Table 25
UK population size: age group by accommodation type
Age group
0-19
20-59
60-64
65-74
75-79
80-84
85-89
90+
TOTAL
Household resident
14, 546, 294
31, 418, 209
2, 863,037
4, 883, 101
1, 906, 995
1, 227, 133
641, 055
256, 633
57, 742, 457
Communal
establishment
222, 328
381, 277
17, 037
53, 159
60, 093
86, 459
110, 980
115, 391
1, 046, 724
Table 26
UK population size: age group by accommodation type and selective
age groups
Age group
60-64
65-74
75-84
85+
Household resident
2, 863,037
4, 883, 101
3, 134, 128
897, 688
76
Communal
establishment
17, 037
53, 159
146, 552
226, 371
Table 27
England and Wales population size: age group by accommodation type
Age group
0-19
20-59
60-64
65-74
75-79
80-84
85-89
90+
Household resident
Communal
establishment
12, 841, 991
27, 796, 483
2, 530, 113
4, 321, 768
1, 703, 334
1, 102, 903
578, 595
232, 452
51, 107, 639
202, 335
343, 579
14, 641
45, 264
51, 689
75, 411
98, 083
103, 275
934, 277
Table 28
Scotland population size: age group by accommodation type
Age group
0-19
20-59
60-64
65-74
75-79
80-84
85-89
90+
Household resident
1, 207, 665
2, 743, 223
259, 939
440, 105
159, 275
96, 825
49, 421
19, 552
4, 976, 005
Communal
establishment
16, 490
28, 000
1, 794
5, 928
6, 248
8, 164
9, 820
9, 562
86, 006
Table 29
Northern Ireland population size: age group by accommodation type
Age group
0-19
20-59
60-64
65-74
75-79
80-84
85-89
90+
TOTAL
Household resident
496, 638
878, 503
72, 985
121, 228
44, 386
27, 405
13, 039
4, 629
1, 658, 813
77
Communal
establishment
3, 503
9, 698
602
1, 967
2, 156
2, 884
3, 077
2, 554
26, 441