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36
THE NEW ARMENIAN MEDICAL JOURNAL
Vol.7 (2013), Nо 4, p.
36-41
ASSESSMENT ON PREVALENCE OF BLINDNESS CAUSING
EYE DISEASES AND THE EYE HEALTH VULNERABILITY
INDEX IN ARMENIA
JRBashYan n.M. 1,2
1 Armenian EyeCare Project, Yerevan, Armenia
2 Department of Mathematical Modeling in Economics, Faculty of Economics, Yerevan State University,
Yerevan, Armenia
ABsTrAcT
Massive eye screenings of population were organized by the Armenian EyeCare Project in the
Republic of Armenia during 2007-2009. Data on eye health of 26,711 persons voluntarily
screened by the Armenian EyeCare Project team were obtained. Taking into account that the
random sampling method was not applied, the acquired data were weighted to obtain age-sex
and regional proportions of population in the country. Within this study the data were also ex-
trapolated to estimate the nationwide indicators for prevalence of eye diseases causing blindness
and to calculate the eye health vulnerability index. Methods of statistical analysis were applied
using the SPSS software.
The analysis of data obtained signifies that in Armenia prevalence of blindness and visual
impairment among the adult (above 16 years old) population was estimated at 0.7% and 4.8%.
correspondingly. The prevalence of cataract was estimated at 8%, glaucoma spread made 1.3%.
corneal diseases: 1.7%, diabetic retinopathy: 1.5%; macular degeneration prevalence amounted
2.3%. Thus, cataract was considered the most widespread eye disease among the adult popula-
tion in Armenia. Nevertheless, the cataract surgical coverage was estimated at 23.8%; hence, a
large part of avoidable blindness related to cataract was not covered by the surgical services.
The proportion of adults (≥16 years old population) with the blindness causing eye disease
revealed at least in one eye was determined as the eye health vulnerability index and estimated
at 13.3%. Among the cohort of persons at the age of ≥50 years old the mentioned index was 3
times higher: 37%.
According to the estimated econometric model, every additional 5 years of life after 50 in-
crease the probability for a person to have vulnerable eye health by about 9%. Taking into ac-
count the estimates on the prevalence of eye diseases, in particular, cataract and its surgical
coverage, as well as the processes of aging in the population of Armenia, the state health policy
in the field of ophthalmology should be adjusted.
Keywords: eye diseases, prevalence, blindness, cataract, surgical coverage.
Address for correspoNdeNce:
Armenian EyeCare Project, Aygestan 5th Street, bldg, 7
Yerevan 0070, Republic of Armenia
Tel: (+374 10) 559 068
E-mail: nairijr@gmail.com
ness were cataract (51%), glaucoma (8%), and
macular degeneration (5%).
Eye diseases and blindness are more wide-
spread among the population above 50 years of
age: the majority ‒ about 82% of all blind people
in the world ‒ persons at the specified age make
[Pascolini D., Mariotti S., 2012].
It should be mentioned that the officially pub-
lished data on eye diseases in the Republic of Ar-
menia include only two main indicators character-
izing the eye health of the country population: a)
Received 4/21/2013; accepted in final form 12/15/2013
intRoduCtion
In accordance to WHO global estimates, 39
million people in the world were blind in 2010
[Pascolini D., Mariotti S., 2012] and the number
of blind people worldwide increased by 1-2 mil-
lion per year [Resnikoff S. et al., 2002]. According
to 2010 data, the main eye diseases causing blind-
37
tHe new ArMeniAn MedicAl JournAl, Vol.7 (2013), No 4, p.
37
36-41 JrBAs hyAN N.m.
general morbidity of the population related to the
diseases of eye and adnexa (with a specification of
glaucoma cases) and b) the number of first-time re-
vealed cases of diseases of eye and adnexa per year.
The cases of morbidity in general population are
registered at the moment of taking medical advice
and during preventive examinations [Health. 2012].
The dynamics of mentioned indicators shows
that in Armenia the general morbidity related to
diseases of eye and adnexa increased 2.5 times in
the period of 2004-2011 and summed up to 3,272
persons per 100,000 population or nearly 88,000
people in 2011 (Figure 1) [Health, 2012]. Further-
more, in 2011 the number of first-time diagnosed
cases also increased (nearly two times in the same
period), while their share in the total eye morbidity
cases comprised nearly 46%. The mentioned up-
ward morbidity trend points out the importance for
estimating prevalence of blindness and main eye
diseases, especially blindness causing ones: cata-
order to estimate main eye health indicators among
the country population; nevertheless, they had only
regional representativeness and their results could
not be applied or distributed to the national level
[Khachatryan N. et al., 2004].
Thus, there is a lack of statistics on country-
wide indicators on prevalence of blindness and
main eye diseases.
The purpose of this article was to present the
estimates on prevalence of main eye diseases caus-
ing blindness in Armenia and the eye health vul-
nerability index (EHVI) within different age
groups of the country population. These estimates
will enable decision-makers to assess the situation
with eye diseases prevalence among the popula-
tion and to determine the needs for specific eye
care services in the country.
MateRial and Method s
Since 2003, the Armenian EyeCare Project
(AECP) medical groups and the Mobile Eye Hos-
pital (MEH) staff involved the overwhelming ma-
jority of country residents from urban and rural
communities in the massive eye screenings. The
Armenian EyeCare Project also carried out MEH-
based laser and surgical treatment of eye diseases
among the poor. Eye screening and examinations
were conducted by a trained team of ophthalmolo-
gists and clinical residents from Yerevan clinics. A
standard protocol for eye examination record was
used at screenings. The examination included vi-
sual acuity tests using Landolt and/or Sivtsev-Gol-
ovin tables. Pinhole vision was tested in those in-
dividuals with visual acuity below 6/18 (either
eye). The assessment of vision loss causes was un-
dertaken using a standard protocol with a direct
ophthalmoscope “Heine Beta 200” (Germany).
Eye pressure was measured by a tonopen or Mak-
lakov tonometer (“Medtronic Tono-pen XL”,
USA).
The AECP completed three medical missions all
over Armenia in the period of 2003-2009. On the
whole, the ophthalmologists visited 841 rural and
urban communities of the country (nearly 90% of
the communities in Armenia). Due to the mentioned
large-scale activities in the specified period, the
AECP had screened and rendered eye services to
around 160,000 persons (around 5% of the country
population). The AECP combined eye screenings of
100 000
90 000
80 000
70 000
60 000
50 000
40 000
30 000
20 000
10 000
02004 2005 2006 2007 2008 2009 2010 2011
Figure 1. Absolute number of registered ( ) and first-
time-revealed ( ) cases of diseases of eye and
adnexa in Armenia [Health, 2012].
ract, glaucoma, age-related macular degeneration,
retinopathy, corneal diseases, etc. Such estimates
are especially important for adjusting the state eye
care policy and priorities to the increased needs of
the country population.
However, among diseases of eye and adnexa
the official statistics specifies only glaucoma
cases. According to 2011 data, in Armenia 7,458
subjects were diagnosed with glaucoma [Health,
2012]. The official statistics on other diseases of
the eye and adnexa, as well as estimates on blind-
ness prevalence, visual impairment and the main
eye diseases causing blindness in different age
groups of population are lacking. Some popula-
tion-based sample surveys were carried out in
38
tHe new ArMeniAn MedicAl JournAl, Vol.7 (2013), No 4, p.
38
36-41
JrBAs hyAN N.m.
the population with relevant information collection
and analysis. Data on the screened people were as-
sembled in the databases (SPSS format). The statis-
tical analysis of outcome data made it possible to
estimate prevalence indices of eye diseases among
the population of Armenia in accordance with the
internationally accepted methodology.
In this article, we present the resulting scien-
tific estimates on the prevalence of main eye dis-
eases among the population of Armenia based on
the AECP screening activities carried out in nine
(out of ten) regions of the country during the AECP
third medical mission in the period of 2007-2009.
Data of precisely this period were selected for
analysis taking into consideration two reasons: 1)
regular upgrades/updates of the AECP question-
naires and filled-in forms secured a more detailed
breakdown according to eye diseases; 2) these data
embraced the most recent updates. During the third
mission, AECP medical groups screened 26,711
persons (or around 0.9% of the country popula-
tion) from 615 different urban and rural communi-
ties of Armenia; among the mentioned cohort
25,516 or 95.5% were adults (above 16 years old).
It is worth mentioning that the AECP database is
not a result of population-based random sampling
survey, since the participation of the population in
the AECP screening was of a voluntary nature. For
that reason, the bulk of obtained data was weighted
to obtain the age-sex (the 5-year age interval) and
geographic (rural-urban and regional) proportions
of the screened population to the demographic and
geographic characteristics of the country. Data were
also extrapolated to estimate the nationwide indica-
tors for prevalence of blindness causing eye dis-
eases and to calculate the EHVI.
The estimations and indicators were calculated
for the adult population (≥16 years old) and, par-
ticularly, for the population in the cohort of ≥50
years old, taking into account that: a) the latter co-
hort was the main age group at risk and b) the pro-
cesses of population aging were obvious in Arme-
nia. On the scale of the United Nations demo-
graphic aging, if the proportion of the population
aged 65 and over comprises more than 7% of the
country population, it is assumed that the popula-
tion is aging. In Armenia, at the beginning of 2012
the proportion of the population aged 65 years and
over comprised about 10%.
Results and disCussion
According to WHO definition, blindness corre-
sponds to the visual acuity of less than 3/60 (0.05) in
the better eye, with the best possible correction. Peo-
ple with visual acuity below 6/18, but equal to or bet-
ter than 3/60 (0.05-0.33) in the better eye, with the
best possible correction are considered as having low
vision. The “visual impairmentˮ definition includes
low vision and blindness [A framework, 2002].
During the third mission AECP doctors found
out 3,147 subjects with visual impairment among
the population screened in Armenia during 2007-
2009. Among the mentioned cohort, 425 persons
were blind and 2,722 had low vision. In order to
estimate the nationwide indicators of visual im-
pairment prevalence, the data obtained were
weighted for adjustment of the age-sex and re-
gional distributions of the screened population in
accordance to those of countrywide proportions.
Upon the subsequent data extrapolation we as-
sessed the prevalence of blindness (visual acuity
less than 3/60 in the better eye, with the best pos-
sible correction) and low vision (visual acuity in
the better eye, with the best possible correction
3/60-6/18) at the national level. According to our
estimates, 0.7% of the country population was
blind (95% confidence interval 0.5÷0.9), 4.1%
(95% confidence interval 3.9÷4.4) had low vision,
and in total 4.8% of population had visual impair-
ment (95% confidence interval 4.4÷5.3).
It should be mentioned that according to WHO
estimates, the prevalence of low vision in Cauca-
sus is 2-3%, while the prevalence of blindness is
0.3-0.6%. Nonetheless, blindness prevalence esti-
mates for Armenia obtained by AECP team were
close to the upper threshold set by the WHO for
the Caucasus, while the visual impairment (visual
acuity in the better eye, with the best possible cor-
rection less than 6/18) estimates exceeded the
upper threshold by 1.2 percentage points (Table 1).
In Armenia the prevalence of visual impairment
was nearly 2 times higher among the population
above 50 years of age: almost 43% of subjects with
visual impairment were in this age category.
In Armenia the main cause of visual impair-
ment is cataract. It makes around 50.6% of the
cases of visual impairment.
According to our results, among adults with vi-
sual impairment, 7.9% had glaucoma, 22% had
39
tHe new ArMeniAn MedicAl JournAl, Vol.7 (2013), No 4, p.
39
36-41 JrBAs hyAN N.m.
fundus-related problems, and 15% had corneal
diseases (Figure 2).
Visual impairment caused by cataract is avoid-
able through the surgical intervention applied in
appropriate time. According to our estimations,
2.3% of adult population of the country underwent
cataract surgery in one eye and another 0.7% ‒ in
two eyes. Based on AECP data, the percent indica-
tor of cataract surgical coverage (CSC) reflecting
the proportion of operated cataract cases in the
total number of operable cataract cases was calcu-
lated using the following formula:
CSC = x+y x 100
x+y+z
where: x = number of persons with unilateral
(pseudo) aphakia and operable cataract in the other
eye; y = number of persons with bilateral (pseudo)
aphakia; and z = number of persons with bilateral
operable cataract.
Among people with operable cataract the share
of those, who underwent cataract surgery in one or
both eyes, was estimated at 23.8%. For compari-
son: even in developing countries the indicator of
CSC is much higher, e.g. 63% in India and 44% in
Pakistan [Jadoon Z. et al., 2007].
According to the estimates based on AECP data,
in Armenia the most widespread eye diseases
among the adult (≥ 16 years old) population were
those of the eye anterior segment (21.9%), cataract
(8.4%) and different pathology states of the ocular
fundus (7.9%) (Table 2).
Estimates on prevalence of the most serious
TAB le 1.
Estimates of visual impairment prevalence in Armenia (%)
Age groups among the total adult population Blindness: Low vision: Visual impairment:
According to AECP 2007-2009 database
≥16 years old 0.7 4.1 4.8
≥ 50 years old 1.6 6.8 8.4
WHO estimation for the Caucasus
lowest estimation for the adult population 0.3 2.0 2.3
highest estimation for the adult population 0.6 3.0 3.6
figuRe 2. Causes of visual impairment among the adult
population of Armenia (% of adults with visual
impairment).
Cataract
Glaucoma Fundus
diseases
Others
Corneal diseases
15% 4.5%
22%
50.6%7.9%
TABle 2.
Estimates of the main eye diseases prevalence in Armenia
Eye diseases Among the total adult population (%)
Eye anterior segment diseases, including: 21.9
- corneal diseases 1.7
Cataract 8.4
Non-glaucomatous diseases of optic nerve 1.2
Glaucoma 1.3
Fundus-related diseases, including: 7.9
- diabetic retinopathy 1.5
- hypertensive retinopathy 2.1
- macular degeneration 2.3
40
tHe new ArMeniAn MedicAl JournAl, Vol.7 (2013), No 4, p.
40
36-41
JrBAs hyAN N.m.
adult people having eye diseases causing blindness
is 13.3% in the country. On the other hand, 37% of
the population above 50 years of age (or almost
every 3rd among them) had vulnerable eye health,
i.e. had at least one disease causing blindness. It
means that the EHVI among the population above
50 years of age was 2.8 times higher than among
the adult population on the whole.
Moreover, among the population above 50 years
there was a clear linear relationship between age
and vulnerability of eye health, which was natural.
The lowest EHVI score was found among the popu-
lation in the age group of 50-54 (23.8%). For the
age group of 80 years and above, about 73% of sub-
jects had vulnerable eye health. We performed a
quantitative assessment of the relationship between
age and vulnerability of the eye health. Estimation
of the linear regression model showed that every ad-
ditional 5 years of life after the age of 50 increased
the probability of a person to have vulnerable eye
health by about 9% (Figure 4). These results are
particularly important, given the mentioned pro-
cesses of aging in the population of Armenia.
blindness causing eye diseases have a special im-
portance from the point of view of blindness pre-
vention. In this study glaucoma, cataract, corneal
diseases, diabetic retinopathy and macular degen-
eration were considered as the most serious eye
diseases causing blindness. As already noted, eye
diseases are more prevalent among the population
above 50 years of age. We obtained quantitative
estimates on the prevalence of the above-men-
tioned diseases not only among the general adult
population, but also among the population above
50. According to our results, in the age group of ≥
50 years old, the prevalence of cataract is 3.2 times
higher than among the general adult population
and comprises 27% vs. 8.4%, the prevalence of
macular degeneration is almost 3 times higher and
comprises 6.5% vs. 2.3%, the prevalence of glau-
coma is 2.6 times higher comprising 4% vs.1.3%,
and the prevalence of diabetic retinopathy is 3
times higher: 4.4% vs. 1.5% (Figure 3).
Based on the estimates on prevalence of main
30
25
20
15
10
5
0 CD Cat Glau DR MD
figure 3. The estimates on prevalence of main eye dis-
eases in Armenia among the population above 50
years of age ( ) and among the adult (16+ years
old) ( )population on the whole.
noteS : CD - Corneal diseases; Cat - Cataract;
Glau - Glaucoma; DR - Diabetic retinopathy;
MD - Macular degeneration.
eye diseases causing blindness, the EHVI was cal-
culated for adult (above 16 years old) and above 50
years of age population in Armenia. People with
corneal diseases, cataract, glaucoma, diabetic reti-
nopathy and/or macular degeneration were consid-
ered as having vulnerable eye health. The EHVI
was calculated as a percentage of subjects having
at least one of the mentioned diseases in the total
number of population in the corresponding age
group. The calculations showed that the share of
Figure 4. Eye health vulnerability index (EHVI) for population
by age subgroups and the linear regression estimation (%).
50-54 55-59 60-64 65-69 70-74 75-79 ≥80
Age groups, years
Eye health vulnerability, %
90
80
70
60
50
40
30
20
10
0
ConClusion
According to official data, in Armenia the gen-
eral morbidity related to the diseases of eye and
adnexa increased in population by 2.5 times dur-
ing 2004-2011. According to our findings, 4.8 %
of adults (16 years old and above) had visual im-
pairment, among which 0.7% were blind. The
main cause of visual impairment was cataract
(51% of the visual impairment cases). It should
be mentioned that the most prevalent eye diseases
among the adult population in Armenia were cata-
41
tHe new ArMeniAn MedicAl JournAl, Vol.7 (2013), No 4, p.
41
36-41 JrBAs hyAN N.m.
racts (8.4%) and the fundus-related diseases
(7.9%). Nevertheless, the CSC was quite low in
the country and comprised about 24%. Thus, the
majority of blindness and visual impairment cases
associated with cataract were not covered by sur-
gical services.
Eye diseases were more prevalent among the
population over 50 years of age. In this age group
the prevalence of visual impairment was 1.8 times
higher than among the adult population in general
and comprised 8.4%; the prevalence of cataract
comprises 27%, macular degeneration ‒ 6.5%,
glaucoma ‒ 3.4%, diabetic retinopathy ‒ 4.4%. As
revealed by our study, 13.3% of the tested adult
persons in Armenia had at least one eye disease
that led to blindness: diseases of the cornea, cata-
ract, glaucoma, diabetic retinopathy, macular de-
generation, i.e., these subjects had vulnerable eye
health. Among the population aged over 50 years
the share of people with the vulnerable eye health
was almost 3 times higher compared to the general
adult population and comprised 37%.
Every additional 5 years of life after 50 increase
the probability of having a vulnerable eye health
by about 9%. Taking into account the estimates on
the prevalence of eye diseases, and, particularly, of
cataract and its surgical coverage, as well as the
processes of aging in the population of Armenia,
state health policy in the field of ophthalmology
should be adjusted.
1. A framework and indicators for monitoring
VISION 2020 – The Right to Sight: The
Global Initiative for the Elimination of Avoid-
able Blindness. World Health Organization.
Geneva. Switzerland. 2002. http://whqlibdoc.
who.int/hq/2003/WHO_PBL_03.92.pdf
2. Health and Health Care of Armenia. Annual
Statistical Report 2011. Health Information-
Analytic Center NIH MOH RA. http://www.
moh.am/uploadfiles/cucanish.pdf. 15.07.2013
3. Jadoon Z., Shah S.P., Bourne R., Dineen B.,
Khan M.A., Gilbert C.E., Foster A., Khan
M.D. Cataract prevalence, cataract surgical
coverage and barriers to uptake of cataract
surgical services in Pakistan: the Pakistan
National Blindness and Visual Impairment
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