Global Estimates on the Number of
People Blind or Visually Impaired
by Diabetic Retinopathy: A
Meta-analysis From 1990 to 2010
Diabetes Care 2016;39:1643–16 49 | DOI: 10.2337/dc15-2171
OBJECTIVE
To estimate global and regional trends from 1990 to 2010 of the prevalence and
number of persons visually impaire d specificall y by diabetic retinopathy (DR) , as a
complication of the precipitous trends in global diabetes, is fundamental for
health planning purposes.
RESEARCH DESIGN AND METHODS
The meta-analysis of published population studies from 1990 to 2012 for the Global
Burden of Disease Study 2010 (GBD) yielded estimated global regional trends in DR
among other causes of moderate and severe vision impairment (MSVI; presenting
visual acuity <6/18, ‡3/60) and blindness (presenting visual acuity <3/60).
RESULTS
Globally in 2010, out of overall 32.4 million blind and 191 million visually impaired
people, 0.8 million were blind and 3.7 million were visually impaired because of
DR, with an alarming increase of 27% and 64%, respectively, spanning the two
decades from 1990 to 2010. DR accounted for 2.6% of all blindness in 2010 and
1.9% of all MSVI worldwide, incre asing from 2.1% and 1.3%, re spectively, in 1990.
These figures were lower in regions with younger populations (<2% in East and
Southeast Asia and Oceania) than in high-income regions (Nort h America, West-
ern Europe, and Australasia) with relatively aging populations (>4%).
CONCLUSIONS
The n umber of persons with visual impairm ent due to DR world wide is rising and
represents an increasi ng proportion of all blindness/MSVI causes. Age-standardized
prevalence of DR-related blindness/MSVI was higher in sub-Saharan Africa and South
Asia. One out of 39 blind people had blindness due to DR, and 1 out of 52 visually
impaired people had visual impairment due to DR.
Data on the p revalence of visual impairment and blindness, its causes, a nd its
changes over time is of high importance for public health issues. On the basis of
previous la rge-scale popula tion-based studies and meta-analyses, diabetic retinop-
athy (DR) has been recognized as one of the most common and important causes for
visual impairment and blindness (1–19). These studies in general showed that DR
was the leading cause of blindness globally among working-aged adults and there-
fore has a significant socioeconomic impact (20–22). Although timely treatment of
DR can reduce the risk of visual loss by 60%, the proportion of blindness due to DR
1
Nova Southeastern University, Fort Lauderdale,
FL
2
Vision and Eye Research Unit, Anglia Ruskin
University, Cambridge, U.K.
3
School of Computer Science and Heinz College,
Carnegie Mellon University, Pittsburgh, PA
4
Department of Ophthalmology, Medical Faculty
Mannheim, Heidelberg University, Mannheim,
Germany
5
L V Prasad Eye Institute, Hyderabad, India
6
African Vision Research Institute, University of
KwaZulu-Natal, Durban, South Africa
7
Brien Holden Vision Institute, Sydney, Australia
8
NHMRC Centre for Clinical Eye Research, Flin-
ders University, Adelaide, Australia
9
Department of Genes and Environment, Divi-
sion of Epid emiology, Norwegian Institute of
Public Health, Oslo, Norway
10
Singapore Eye Research Institute, Duke-NUS
Graduate Medical School, National Univer sity
of Singapore, Singapore
11
Melbourne School of Population and Global
Health, University of Melbourne, Australia
Corresponding author: Rupert R.A. Bourne, rb@
rupertbourne.co.uk.
Received 3 October 2015 and accepted 25 May
2016.
This article contains Supplementary Data online
at http://care.diabetesjournals.org/lookup/
suppl/doi:10.2337/dc15-2171/-/DC1.
J.L.L. and R.R.A.B. share the first authorship.
S.R. and H.R.T. share the last or senior authorship.
*A complete list of the members of the Vision Loss
Expert Group can be found at http://www.anglia
.ac.uk/epidemiology%20/.
© 2016 by the American Diabetes Association.
Readers may use th is article as long as the work
is properly cited, the use is educational and not
for profit, and the work is not altered. More in-
formation is available at http://diabetesjournals
.org/site/license.
Janet L. Leasher,
1
Ruper t R.A. Bourne,
2
Seth R. Flaxman,
3
Jost B. Jonas,
4
Jill Keeffe,
5
Kovin Naidoo,
6,7
Konrad Pesudovs,
8
Holly Price,
2
Richard A. White,
9
Tien Y. Wong,
10
Serge Resnikoff,
7
and Hugh R. Taylor,
11
on
behalf of the Vision Loss Expert Group of
the Global Burden of Disease Study*
Diabetes Care Volume 39, Septemb er 2016 1643
META-ANALYSIS
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ranged from 3 to 7% in the Southeast
Asia and Wester n Pacific regions and
wasashighas15–17% in developed re-
gions such as the Americas and Europe (23).
A previous meta-analysis (21) summa-
rizing 35 studies with more than 20,000
patients with diabetes estimated a prev-
alence of any DR of 34.6%, of diabetic
macular edema of 6.8%, and of vision-
threating DR of 10.2% within the diabetes
population. The prevalence estimates of
any DR and vision-threatening DR varied
with ethnicity and were highest in African
Americans and lowest in Asians. By ex-
trapolating these prevalence rates to
the 2010 world diabetes population, Yau
et al. (21) estimated that ;93 million
people had some DR and 28 million peo-
ple had sight-threatening stages of DR.
However, this meta-analysis did not ad-
dress the prevalence of visual impairment
and blindness due t o DR and thus the
impact of DR on the general population.
No previous studies assessed changes in
the prevalence of DR-related blindness
from 1990 to 2010 or the number of peo-
ple functionally affected applying the
same methodology across all time periods.
We therefore conducted the present
meta-analysis of all available population-
based studies performed worldwide
within the last two decades as part of
the Global Burden of Disease Study
2010 (GBD) to e stimate th e number
of people affected by blindness and visual
impairment. The global prevalence,
causes, and regional estimates have been
reported previously (24,25). Because the
numbers of persons living with diabetes
and DR have triggered a global public
health respon se, we be lieve that it is
imperative to present the figures we esti-
mated specifically for blindness and visual
impairment due to DR in the present anal-
ysis. Along with the global and regional
figures, we offer the temporal trends
from 1990 to 2010; we examine regional
differences in the prevalence of DR-related
blindness and moderate and severe vision
impairment (MSVI); a nd we consider th e
implications of how the number of people
with DR-related blindness and visual im-
pairment compares with the number of
people with blindness and visual impair-
ment due to other eye diseases.
RESEARCH DESIGN AND METHODS
The GBD methodology is detailed else-
where (24–26). Herein we shall only re-
view the methodology pertinent to the
present analysis of the prevalence of vi-
sual impairment due to DR. A systemic
literature review yielded 14,908 relevant
articles published between 1980 and
2012 primarily identified by search ing
Medline, Embase, and the World Health
Organization (WHO) library information
system. (The full search strategy is in-
cluded in Supplementary Appendix 1.) Of
those, 243 population-based studies were
analyzed after review by an expert panel of
ophthalmologists, optometrists, and oph-
thalmic epidemiologists. The search terms
applied included “blindness,”“visual im-
pairment,”“population,”“eye,”“survey,”
and a list of ocular disorders (24,25). Ad-
ditionally, personal communication with
principal investigators identified in the lit-
erature search provided additional u n-
published data sources (24,25).
In the GBD, blindness was defined as
presenting visual acuity ,3/60 and MSVI
as presenting visual acuity ,6/18, $3/60.
Population-based studies that reported
prevalence of visual impairment and
blindness disaggregated by cause (128
studies) provided the basic data to calcu-
late the proportion of blindness and MSVI
due to DR (20 studies) in addition to other
causes such as cataract, age-related mac-
ular degeneration, glaucoma, trachoma,
or undercor rection of refractive error
(24). Ten of the 21 (47.6%) GBD regions
(27) were represented with data o n
DR-related blindness/MSVI (Australasia,
Central and Western Europe, North
America, Caribbean, Tropical Latin
America, Oceania, and South, East, and
Southeast Asia). On a country level,
studieswereavailablefor14outof
191 countries.
Trend s in causes of vision impairment
were calculated by age in 5-year in-
crements, sex, and GBD region. We ad-
ditionally performed an analysis of
uncertainties. The statistical analysis in-
cluded the data identification and acces-
sibility; the estimation of fractions for
each cause stratified by the severity of
vision impairment, sex, age, and region;
and the application of cause fractions to
the prevalence of all-cause presenting vi-
sion impairment (24). The statistical anal-
ysis applied the DisMod-MR (https://
github.com/ihmeuw/dismod_mr) model
to calculate the fraction of vision impair-
ment due to DR and the other causes
mentioned above (24). The DisMod-MR
is a negative binomial regression model in-
cluding the following elements: covariates
that predict variation in the true propor-
tion of vision impairment from each dis-
ease (e.g., year); fixed effects that adjust
for definitional differences (e.g., whether
the causes of presenting vs. best-corrected
vision impairment were reported); a hier-
archical model structure that fits random
intercepts in individual countries derived
from the data observed in the country, in
its region, and in other regions on the basis
of the availability and consistency of
country- and region-specific data; age-
specific fixed effects allowing for a nonlinear
age pattern; and a fixed effect for data on
males. The fraction of blindness and visual
impairment due to DR resulted from fitting
one DisMod-MR model using three covari-
ates: an indicator variable describin g
whether the data were for blindness or
for MSVI, an indicator variable describing
whether the data were based on presenting
visual acuity or best-corrected visual
acuity measurements, and a country-
level covariate re flec ting health systems
access. T wo sets of predictions for DR
were generated, one for best-corrected
blindness and one for best-corrected
MSVI. Age-standardized prevalence rep-
resented the WHO reference population
(28). The generation of numbers of peo-
ple with vision impairment and blindness
due to DR reflects each region’spopula-
tion size and age structure (24,25).
RESULTS
Our overall estimates suggest that 32.4
million people were blind and 191 million
people were visually impaired worldwide
in 2010 (24). Of these, 833,690 people
were blind and 3.7 million were visually
impaired because of DR (Table 1). Data
for 1990 are presented in Supplementary
Appendix 2. From 1990 to 2010, the num-
ber of people with blindness due to DR
increased by ;176,000 or 27% and the
number with visual impairment due to
DR increased by 1.4 million or 64% (Table
1 and Supp lementary App endix 2). In
2010, South Asia was home to 35% o f
those with blindness due to DR (294,811)
and 40% of those with visual impairment
due to DR (1.5 million) (Table 1, Supple-
mentary Appendix 2, and Figs. 1 and 2). Of
those aged 50 years and older, the num-
ber of people with blindness due to
DR increased from 574,000 in 1990 to
731,000 in 2010 and the number of peo-
ple with DR-related visual impairment
increased from 1,858,000 in 1990 to
3,074,00 0 in 2010.
1644 Diabetic Retinopathy Visu al Impairment Worldwide Diabetes Care Volume 39, Septemb er 2016
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Table 1—Number of people (mean [95% UI]) with blindness (presenting visual acuity <3/60) or MSVI (presenting visual acuity <6/18, ‡3/60) due to DR, the age-standardized prevalence
(%) in people aged ‡50 years (mean [95% UI]), and the percentage of all blindness or MSVI attributed to DR (95% UI) in 21 world regions in 2010
Blindness due to DR
MSVI due t o DR
World region
2010 total
population (’000s)
Number of people
(’000s) with
blindness in 2010
Age-standardiz ed prevalence
of blindness in peo ple
aged $50 years in 2010
Percentage of all
blindness in 2010
Number of people
(’000s) with MSVI
in 2010
Age-standardized
prevalence of MSVI
in people aged
$50 years in 2010
Percentage of
MSVI in 2010
World 6,890,000 834 (703, 1,102) 0.05 (0.04, 0.07) 2.6 (2.2, 3.4) 3,714 (3 ,128, 5,471) 0.22 (0.18, 0.31) 1.9 (1.6, 2.7)
Asia Pacific, high income 169,000 15 (8, 31) 0.02 (0.01, 0.03) 4.3 (2.6, 7.1) 61 (38, 226) 0.07 (0.04, 0.26) 3.1 (2.0, 5.4)
Asia, Central 68,800 5 (4, 10) 0.04 (0.02, 0.06) 4.0 (2.9, 6.0) 33 (21, 73) 0.21 (0.13, 0.48) 2.8 (2.1, 4.6)
Asia, East 1,190,000 58 (3 2, 111) 0.02 (0.01, 0.03) 1.1 (0.61, 2.0) 279 (153, 567) 0.07 (0.04, 0.15) 0.84 (0.49, 1.6)
Asia, South 1,120,000 295 (167, 514) 0.12 (0.07, 0.21) 2.8 (1.7, 4.8) 1,450 (8 64, 2,873) 0.51 (0.29, 0.96) 2.1 (1.2, 3.7)
Asia, Southeast 460,000 499 (35, 76) 0.12 (0.03, 0.07) 1.4 (1.1, 2.1) 223 (154, 427) 0.19 (0.13, 0.36) 1.2 (0.91, 1.9)
Australasia 20,500 2 (0.9, 5) 0.02 (0.01, 0.05) 4.3 (2.5, 7.7) 13 (5, 42) 0.14 (0.06, 0.42) 2.9 (1.8, 5.9)
Caribbean 34,300 5 (3, 8) 0.05 (0.03, 0.08) 2.3 (1.7, 3.4) 24 (15, 42) 0.24 (0.14, 0.41) 2.0 (1.5, 3.2)
Europe, Central 122,000 12 (8, 27) 0.03 (0.02, 0.06) 3.7 (2.8, 5.5) 84 (49, 174) 0.18 (0.10, 0.36) 2.5 (1.8, 4.0)
Europe, Eastern 222,000 24 (11, 48) 0.03 (0.01, 0.06) 4.0 (2.5, 6.9) 166 (65, 371) 0.21 (0.08, 0.47) 2.8 (1.8, 5.2)
Europe, Western 381,000 40 (28, 68) 0.02 (0.01, 0.03) 4.2 (3.4, 5.9) 225 (153, 426) 0.12 (0.08, 0.22) 3.0 (2.4, 4.5)
Latin America, Andean 38,600 5 (3, 9) 0.05 (0.03, 0.09) 2.5 (1.6, 4.2) 31 (18, 55) 0.32 (0.19, 0.55) 2.2 (1.5, 3.8)
Latin America, C entral 166,000 23 (16, 38) 0.06 (0.04, 0.09) 2.5 (1.9, 3.7) 109 (74, 192) 0.25 (0.17, 0.44) 2.1 (1.6, 3.5)
Latin America, Southern 48,900 12 (8, 26) 0.07 (0.04, 0.14) 5.5 (3.6, 9.1) 64 (37, 139) 0.36 (0.21, 0.77) 4.0 (2.6, 6.8)
Latin America, Tropical 154,000 23 (12, 51) 0.05 (0.03, 0.12) 2.9 (1.9, 4.6) 108 (62, 204) 0.24 (0.14, 0.45) 2.2 (1.4, 3.6)
North Africa/Middle East 301,000 108 (76, 165) 0.16 (0.11, 0.25) 3.5 (2.8, 5.0) 334 (233, 567) 0.44 (0.31, 0.75) 2.4 (1.8, 3.9)
North America, high income 281,000 19 (10, 34) 0.01 (0.01, 0.03) 3.9 (2.7, 6.4) 86 (56, 195) 0.07 (0.04, 0.15) 2.8 (1.9, 4.7)
Oceania 5,814 0.4 (0.2, 0.9) 0.05 (0.02, 0.09) 1.4 (0.91, 2.4) 3 (2, 6) 0.26 (0.13, 0.47) 1.2 (0.77, 2.3)
Sub-Saharan Africa, Central 53,400 8 (4, 23) 0.10 (0.05, 0.25) 3.0 (2.0, 5.2) 33 (18, 82) 0.33 (0.1 8, 0.80) 2.3 (1.6, 4.0)
Sub-Saharan Africa, East 208,000 50 (35, 76) 0.14 (0.10, 0.20) 2.4 (1.9, 3.4) 128 ( 92, 204) 0.31 (0.21, 0.49 ) 1.8 (1.4, 2.6)
Sub-Saharan Africa, South 52,600 10 (5, 20) 0.10 (0.05, 0.20) 3.4 (2.1, 5.8) 24 (14, 55) 0.22 (0.12, 0.50) 2.5 (1.6, 4.6)
Sub-Saharan Africa, West 201,000 66 (44, 107) 0.19 (0.12, 0.31) 3.1 (2.4, 4.9) 193 (125, 249) 0.50 (0.32, 0.92) 2.7 (1.9, 4.5)
care.d iabetesjournals.org Leasher and Associates 1645
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DR caused 2.6% of all cases with
blindness worldwide in 2010 and 1.9%
of all cases for MSVI (Table 1). The per-
centage of blindness caused by DR var-
ied regionally from ,2% in East and
Southeast Asia and Oceani a to $5.5%
in Southern Latin America (Table 1).
World regions with older populations
such as the high-income regions, South-
ern Latin America, and Eastern and West-
ern Europe, as compared with regions
with relatively younger populations,
showed a higher percentage of blindness
caused by DR (Table 1).
Compared with 1990, of all global
blindness causes, the percentage caused
by DR increased from 2.1 to 2.6% in
2010, and of global MSVI causes, the
Figure 1—Number of people wi th blindness due to DR in 1990 and 2010 by world region of all ages and the age-standard ized preva lence in 1990 and
2010 by world region of those aged $50 years ( 95% UI).
Figure 2—Number of people with MSVI due to DR in 1990 and 2010 by world region of all ages and the age-standardized prevalence in 1990 and
2010 by world region of those aged $50 years ( 95% UI).
1646 Diabetic Retinopathy Visu al Impairment Worldwide Diabetes Care Volume 39, Septemb er 2016
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percentage caused by DR increased
from1.3to1.9%in2010(Table1and
Supplementary Appendix 2). The in-
crease in the percentage of global
blindness caused by DR from 1990 to
2010 took place in all world regions ex-
cept those higher-income regions of Asia
Pacific, Australasia, Western Europe, and
North America where a slight decrease
occurred (Table 1 and Supplementary
Appendix 2).
Age-standardized prevalence of
DR-related blindness and MSVI in those
aged $50 y ears was rel atively un-
changed wor ldwide. Age-standardized
prevalence of blin dness due to DR
changed to 0.0518% (95% uncertainty
interval [UI] 0.0440, 0.0690) in adults
aged $50 years in 2010 from 0.0652%
(95% UI 0.0565, 0.0812) in 199 0. Age-
standardized prevalence of MSVI due to
DR changed to 0.2185% (95% UI 0.1843,
0.3135) in 2010 from 0.2093% (95% UI
0.1689, 0.2635) in 1990 (Table 1, Sup-
plementary Appendix 2, and Figs. 1
and 2).
On a regional basis, in 2010, the age-
standardized prevalence of blindness
related to DR in those aged $50 years
was highest in West sub-Saharan Africa
(0.18 89%) and North Africa/Middle East
(0.1599%), followed by East sub-
Saharan Africa (0.1366%), and 0.1% or
less in all other regions (T able 1). In
2010, the age-st andardized prevalence
of MSVI due to DR in those aged $50 years
was highest in South Asia (0.5112%), West
sub-Saharan Africa (0.5002%), and North
Africa/Middle East (1.0%) and lowest in
the high-income regions such as North
America (Table 1).
CONCLUSIONS
DR ranks as the fifth most c ommon
cause of global blindness and of global
MSVI (25). Regardless of the relatively
low percentage of ,3% of all global
blindness and MSVI being caused by
DR, this analysis estimates that, in
2010, 1 out of every 39 blind people
had blindness due to DR and 1 o ut of
every 52 people had visual impairment
due to DR. In adults aged $50 years, the
global age-standardized prevalence in
2010 was 0.05% for DR-related blind-
ness and 0.22% for DR-related MSVI.
The prevalence of any DR has been
previously reported in a number of
population-based studies (1–23). How-
ever, few addressed the prevalence of
DR-related blindness at the global level.
Within the period from 1990 to 2010,
the age-standardized prevalence of DR-
related blindness and MSVI did not
markedly change as a global mean. This
is in contrast to the global decrease in
the age-standardized prevalence of cat-
aract, undercorrected refractive error,
and trachoma (24,25). Our study demon-
strated regional differences such as the
increase in age-standardized prevalence
observed in sub-Saharan regions and
how the highest age-standardized prev-
alence of DR-related blindness and MSVI
was in the regions of North Africa/
Middle East, sub-Saharan Africa, and
South Asia and the lowest prevalence
was in the high-income regions. Similar
interregional findings were reported in a
recent meta-analysis (21) where preva-
lence estimates of any DR and of vision-
threatening DR were highest in African
Americans and lowest in Asians.
We propose that the phenomenon of
an increase in numbers of people with
vision loss due to DR with a relatively
unchanged age-standardized preva-
lence of vision loss due to DR from
1990 to 2010 globally can be at tributed
to the increasing population and aver-
age age in most reg ions coup led wi th
falling death rates (27).
Our d ata suggest that the percentage
of blindness and MSVI attributable to
DR was lower in low-income regions
with younger populations than in high-
income regions with older populations.
There are seve ral reasons that may ex-
plain this observation. First, low-income
societies may have a higher percentage
of unope rated cataract or undercor-
rected refractive error–related blind-
ness and MSVI (25), which is probably
relatedtoaccesstovisualandocular
health services. Therefore, the propor-
tional increase in blindness and MSVI
attributable to DR may be rising b ecause
of th e decreasing proportion attribut-
able to cataract (25) as a result of th e
increasing availability of cataract sur-
gery in many parts of the world (29)
during the past decade. Improved visu-
alization of the fundus afforded by cat-
aract surgery should also improve the
detection of DR. The increase in t he per-
centage of global blindness caused by
DR within the last two de cades took
place in all world regions except West-
ern Europe and high -income N or th
America where there was a slight
decrease. This decrease may refl ect the
effect of intensified prevention and
treatment of DR possibly in part due
to the introduction of intravitreal in-
jections of steroids and anti-VEGF (vas-
cular endothelial growth factor) drugs
(30,31).
Second, in regions with poor medical
infrastructure, patients with diabetes
may not live long enough to experience
DR (32). This reduces the number of pa-
tients with diabetes, and, furthermore,
it reduces the numb er of patients with
DR-related vis ion loss. Stu dies in the lit-
erature have reported that the preva-
lence of severe DR decreased from
1990 to 2010 (21) while the prevalence
of diabetes simultaneously increased
(27), which implies a reduction in the
prevalence of severe DR per person
with diabetes. This paradox is even
more remarkable if one takes into ac-
count that duration of diabetes is one
of the most important risk factors for
the development of DR and for the de-
velopment of se vere DR. For example, in
Central India (19) the prevalence of DR
within the diabetes popula tion was 5%,
which wa s considerably lower than the
global prevalence of 34.6%. In that rural
population in Central India, the preva-
lence of diabetes i n 2006/2008 de-
crea sed after the age of 60 years, and
the prevalence of DR was exceptionally
low compared with populations in in-
dustrialized countries. Differences be-
tween regions in the screening a nd
management of D R and diabetes, socio-
economic factors, medical infrastruc-
ture, ethnic differences, and variation
in genetic susceptibility for DR may
also explain some of these differences
(22). Interestingly, the age-standardized
prevalence of DR-related blindness and
MSVI were as low in South Asia as in
high-income regions, despite marked
regional differences in socioeconomic
levels and medic al infrastructure.
Third, as in the case of Centra l In dia
described above (19), younger popula-
tionsmayhavealowerprevalenceof
diabetes (33). If we apply our prevalence
results to the number of people with
diabetes reported by Danaei et al. (34),
;350 million, our figures would suggest
that ;0.2% (or 834,000 people) of the
350 million were blind because of DR
and that 1.1% (or 3.7 million individuals)
of the 350 million with diabetes were
visually impaire d because o f DR. These
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