Visual impairment and blindness in Hungary - Wiley Online Library

Acta Ophthalmologica 2017

Visual impairment and blindness in Hungary Dorottya Szab o,1 G abor L aszl o S andor,1 Gabor T oth,1 Anita Pek,1,2 Regina Lukacs,1,3 Iren Szalai,1 1 1 Georgina Zs ofia T oth, Andr as Papp, Zoltan Zsolt Nagy,1 Hans Limburg4 and Janos Nemeth1 1

Department of Ophthalmology, Semmelweis University, Budapest, Hungary Department of Ophthalmology, Petz Aladar Hospital, Gy} or, Hungary 3 Department of Ophthalmology, Fl or Ferenc Hospital, Budapest, Hungary 4 Health Information Services, Grootebroek, The Netherlands 2

ABSTRACT. Aim: The aim of this study was to estimate the prevalence and causes of blindness, severe visual impairment (SVI), moderate visual impairment (MVI), and early visual impairment (EVI) and its causes in an established market economy of Europe. Design: A cross-sectional population-based survey. Methods: A sample size of 3675 was calculated using the standard Rapid Assessment of Avoidable Blindness (RAAB) software in Hungary. A total of 105 clusters of 35 people aged 50 years or older were randomly selected with probability proportionate to size by the Hungarian Central Statistical Office. Households within the clusters were selected using compact segment sampling. Visual acuity (VA) was assessed with a Snellen tumbling E-chart with or without a pinhole in the households. Results: The adjusted prevalences of bilateral blindness, SVI, MVI and EVI were 0.9% (95% CI: 0.6–1.2), 0.5% (95% CI: 0.2–0.7), 5.1% (95% CI: 4.3– 5.9) and 6.9% (95% CI: 5.9–7.9), respectively. The major causes of blindness in Hungary were age-related macular degeneration (AMD; 27.3%) and other posterior segment diseases (27.3%), cataract (21.2%) and glaucoma (12.1%). Cataract was the main cause of SVI, MVI and EVI. Cataract surgical coverage (CSC) was 90.7%. Of all bilateral blindness in Hungary, 45.5% was considered avoidable. Conclusion: This study proved that RAAB methodology can be successfully conducted in industrialized countries, which often lack reliable epidemiologic data. The prevalence of blindness was relatively low, with AMD and other posterior segment diseases being the leading causes, and cataract is still a significant cause of visual impairment. Key words: avoidable blindness – epidemiology – rapid assessment – visual impairment

Acta Ophthalmol. ª 2017 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd

doi: 10.1111/aos.13542

Introduction The World Health Organization (WHO) estimated that globally around 285 million people are visually impaired, of whom 39 million are blind (Lancet, 2011). Although most of the

visually impaired people live in lowincome countries, blindness due to noncommunicable eye diseases remains a significant health problem in Europe. To plan eye care services properly, it is essential to collect reliable epidemiological data, which is lacking in many

European countries. In 1999, the WHO and the International Agency for Prevention of Blindness launched a global campaign called VISION 2020: ‘The Right to Sight’ with the goal to eliminate avoidable blindness by the year 2020. Hungary – as an established market economy in Europe – is participating in this initiative, although recent population-based data on the prevalence and causes of blindness and low vision are missing. According to the last available survey in Hungary performed in 1999, AMD diabetic retinopathy (DR), high myopia, glaucoma and cataract were the leading causes of blindness in Hungary (Nemeth et al. 2005). A questionnairebased study in 2004 suggested that the prevalence of blindness among patients with diabetes in Hungary is 4.2%, which is 2.8 times higher than that in the United Kingdom (Schneider & S€ uveges 2005). Moreover, it is estimated that ~1000 people become blind annually due to diabetes-related ocular complications (Nemeth et al. 2005; Szab o et al. 2015). As most of the population-based surveys are very expensive, time-consuming and complicated to perform, we used a low-cost, rapid methodology, which has been described recently for the reliable epidemiological estimation of avoidable blindness. Rapid Assessment of Avoidable Blindness (RAAB) is a relatively low-cost methodology and rapid, as it only involves the population over 50 years of age in which the prevalence of blindness is the highest (Kuper et al. 2006). We decided to include DR

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module (RAAB+DR) in our project due to the earlier estimated high prevalence of diabetic blindness in Hungary. The findings on diabetes and DR were presented in separate articles (T oth et al. 2017a, 2017b). Over 186 RAAB surveys have been conducted successfully in 65 countries worldwide. The first European RAAB+DR study was completed in Moldova in 2012 (Zatic et al. 2015). The purpose of this article was to present the results of the first completed RAAB+DR study in an industrialized country in Europe. We will summarize these Hungarian epidemiological data on blindness and visual impairment that will allow us to plan eye care services appropriately and help our efforts in advocacy for long-term funding and political support. In addition, we are aiming to discover and detail the disease group so-called ‘other posterior segment diseases’, which is a major contributor to blindness and visual impairment in high-income regions.

Patients and Methods Rapid assessment of avoidable blindness with DR module (RAAB+DR)

The RAAB+DR was conducted between December 2014 and November 2015 (including fieldwork in April– July 2015), covering the population aged 50 years or older in Hungary. This population-based survey was organized by the Department of Ophthalmology, Semmelweis University, and funded by the LCIF SightFirst Research Grant Program. A sample size of 3675 was estimated based on expected prevalence of blindness of 2.5% among adults 50 years of age or older, with a required confidence of 95%, a precision of 25%, a design effect of 1.4% and a 10% noncompliance rate. A total of 105 clusters of 35 people 50 years of age or older were included, which were selected through systematic sampling with a probability proportionate to size from a sampling frame consisting of all census enumeration areas (EA) used in the national census of 2011. Detailed maps of all 105 selected EAs, showing the exact location and boundaries of each EA, were provided by the Hungarian Central Statistical Office. Within each selected EA, eligible households were selected

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using compact segment sampling, whereby each selected EA was divided into segments containing ~35 eligible residents aged ≥50 years. Then one segment was chosen randomly, in which all households were visited by the survey team door to door until 35 people aged 50 years or older were examined (Turner et al. 1996). Households where an eligible person was absent at the time of the visit were revisited two more times on the same day. A person was registered as a nonresponder if not available after three visits. In these cases, household members or neighbours were asked about their likely vision status. If the segment did not include the required 35 eligible survey subjects, the geographically next nearest segment was selected and examinations continued there until 35 records were completed. Before starting the fieldwork, a 5day-long training programme was conducted in Budapest by a certified RAAB trainer. Interobserver variation assessments were conducted for the RAAB eye examination using 50 patients, and for the DR grading using a standardized slide set, to ensure that all teams were capable of making the correct examinations and diagnoses. Tests were conducted until good to excellent agreement was achieved for VA assessment, lens assessment, main cause of visual impairment and DR grading (Kappa at least 0.75). The Department of Ophthalmology, Semmelweis University, provided the office space for training. There were five survey teams, each including an ophthalmologist (senior resident or ophthalmic specialist), an ophthalmic assistant and a health worker/nurse, plus a driver and a local helper. The team leader was the ophthalmologist, who was responsible for eye examinations, for the determination of the main cause of visual impairment or blindness and for checking all survey record forms on the same day for correctness and completeness. The ophthalmic assistant undertook the VA testing; the health worker/nurse was responsible for blood glucose testing. The local worker helped the team identify eligible participants and was the contact person between the survey team and the community. To ensure a good response rate from the survey participants, we also tried to contact all mayor’s offices in the selected survey

areas to inform patients ≥50 years of age about the project. Besides mayors, general practitioners (GPs), local government workers, GP nurses, citizen soldiers, social and public workers were our local helpers. Ophthalmic examination

Visual acuity (VA) was measured by an ophthalmic assistant at the household using a Snellen tumbling E-chart with optotype sizes 6/12, 6/18 and 6/60 at 6 and 3 m (6/60 only) with available correction. Pinhole vision was also measured for eyes with presenting VA < 6/12. Participants were categorized according to VA in the better eye. The classification of visual impairment is in accordance with the International Classification of Diseases (ICD-10) and the revision proposed by WHO: normal vision is considered if VA ≥ 6/12, EVI refers to VA < 6/12–6/18, MVI refers to VA < 6/18–6/60, SVI refers to VA < 6/60–3/60, and blind refers to VA < 3/60. The ophthalmologist examined the lens using a torch light and a direct ophthalmoscope. Only the primary cause of the visual impairment or blindness was recorded on the survey forms. If more than one primary disorder coexists, the one most amenable to treatment or prevention was chosen. Data analysis

All data were recorded on two-page survey record forms. These survey forms were cross-checked daily during the fieldwork to identify and correct the possible mistakes. Data entry was performed by the members of the survey teams (doctors, nurses, assistants), who entered data from these forms into the RAAB software. While one of the members was reading the code numbers out loud, the other person entered these codes in the software, to reduce typing errors. In addition, there are in-built consistency checks in the RAAB software. The RAAB software (version 6) was used for automatic data analysis and generation of reports. Details of the standard calculations by the RAAB software are described in the RAAB6 manual (available at: https://www. cehjournal.org/resources/raab/). The RAAB software calculates prevalence of various conditions in the sample population, as well as age- and sex-adjusted


prevalence. Adjustment is made by calculating age and sex-specific prevalence by sex and by 10-year age group in the sample and extrapolating these sample prevalences against the actual population in the corresponding groups. In this way, the estimated number of people aged 50+, affected by various conditions in entire Hungary, can be calculated, as well as the adjusted prevalence. Ethical approval

The study was approved by the Semmelweis University Regional and Institutional Committee of Science and Research Ethics. The research followed the tenets of the Declaration of Helsinki. Informed written consent was obtained from the participants. All patients who needed further ophthalmic or diabetic examinations were referred accordingly to a healthcare centre.

Results Of 3675 eligible participants, 3523 were examined (95.9%), 71 persons were absent (1.9%), 80 (2.2%) refused to participate, and one was not able to do the tests. Compared to the census data in the study sample, the age group 50– 59 was slightly under-represented, while the 70–79 group was over-represented. Prevalence and causes impairment and blindness

of

visual

The sample prevalence of bilateral blindness with available correction (presenting visual acuity: PVA < 3/60) in people aged 50+ in the better eye is 0.9%: 0.9% in males and 1.0% in females. The prevalence of bilateral SVI is 0.5%, bilateral MVI 5.6% and bilateral EVI 7.5%. The prevalence of functional low vision [best-corrected visual acuity (BCVA) in the better eye of less than 6/ 18 to more than or equal to no perception of light in individuals with untreatable causes of visual loss], requiring low vision services, is 1.9%. The prevalence of MVI in females (6.5%) is significantly higher than in males (4.0%); in the other categories, the differences are not statistically significant (Table 1). Table 2 shows the adjusted prevalence and the estimated number of cases of bilateral blindness, SVI, MVI, EVI and functional low vision of adults aged 50+ in Hungary.

AMD (n = 9) and glaucoma (n = 5) were the main causes. By younger age groups, AMD (by age group 70–79, n = 3) and other posterior segment diseases (age group 60–69, n = 5) turned out to be the leading causes. We found MVI mostly in age group 70–79 (n = 69). Forty-seven MVI cases were found in 80+, 28 in 60–69 and 18 in 50–59 year age group (Fig. 2). In older age groups, MVI is mainly caused by untreated cataract and refractive error. Of all bilateral blindness in Hungary, 45.5% is considered avoidable, 21.2% is considered treatable, 3.0% avoidable by primary eye care (PEC) and 21.2% avoidable by specialized ophthalmic care. Posterior segment diseases account for 72.7% of all bilateral blindness. According to our results, 21.2% of blindness in Hungary can be treated or prevented by cataract surgery, primary health care and PEC activities. Another 21.2% of blindness can be prevented with adequate ophthalmic services. The majority (54.5%), however, are people with permanent blindness who require low vision services. The main intervention strategies to

The prevalence of blindness and low vision increased exponentially with age. In age group 50–59, the prevalence was 2.3% (2.0% MVI, 0.1% SVI and 0.2% blind), which increased to 3.1% by age group 60–69 (2.3% MVI, 0.0% SVI and 0.8% blind), and to 8% by age group 70–79 (7.2% MVI, 0.2% SVI and 0.6% blind). The age group 80+ had the highest prevalence of blindness and low vision, with a total of 17.2% (10.6% MVI, 3.2% SVI and 3.4% blind). In people aged 50+, AMD and other posterior segment diseases were the most common cause of bilateral blindness (PVA < 3/60 in the better eye), both with 27.3%, followed by untreated cataract (21.2%), glaucoma (12.1%) and DR (6.1%). For SVI, MVI and EVI, cataract is the main cause with 35.3%, 49.7% and 42.6%, respectively. Uncorrected refractive errors (URE) are causing 23.9% of MVI and 40.7% of EVI (Table 3). Figures 1 and 2 show the distribution of the principal causes of visual impairment and blindness in different age groups. In the 80+ year age group, where most SVI and blind cases were found, untreated cataract (n = 9),

Table 1. Sample prevalence of blindness, SVI, MVI, EVI and functional low vision in adults aged 50+. Males

Females

Total

Bilateral presenting VA

n

% (95% CI)

n

% (95% CI)

n

% (95%CI)

Blindness (PVA < 3/60) SVI (PVA < 6/60–3/60) MVI (PVA < 6/18–6/60) EVI (PVA < 6/12–6/18) Functional low vision

11 5 51 82 27

0.9 0.4 4.0 6.4 2.1

22 12 146 181 40

1.0 0.5 6.5 8.0 1.8

33 17 197 263 67

0.9 0.5 5.6 7.5 1.9

(0.4–1.4) (0.0–0.9) (2.8–5.2) (4.9–8.0) (1.3–2.9)

(0.6–1.4) (0.2–0.8) (5.4–7.5) (6.8–9.3) (1.2–2.4)

(0.6–1.2) (0.2–0.7) (4.8–6.4) (6.5–8.5) (1.4–2.4)

CI = confidence interval, EVI = early visual impairment, MVI = moderate visual impairment, PVA = presenting visual acuity, SVI = severe visual impairment, VA = visual acuity. Table 2. Age- and sex-adjusted prevalence of blindness, SVI, MVI, EVI, functional low vision and estimated affected people in the Hungarian population aged 50+. Males Bilateral presenting VA Blindness (PVA < 3/60) SVI (PVA < 6/60–3/60) MVI (PVA < 6/18–6/60) EVI (PVA < 6/12–6/18) Functional low vision

Females

Total

n

% (95% CI)

11 817

0.7 (0.3–1.2)

20 959

1.0 (0.6–1.4)

32 776

0.9 (0.6–1.2)

5793

0.4 (0.0–0.9)

11 478

0.5 (0.2–0.8)

17 271

0.5 (0.2–0.7)

55 087

3.5 (2.3–4.6)

136 089

6.3 (5.2–7.3)

191 177

5.1 (4.3–5.9)

93 235

5.9 (4.4–7.4)

166 796

7.7 (6.5–8.9)

260 036

6.9 (5.9–7.9)

29 176

1.8 (1.0–2.7)

37 109

1.7 (1.1–2.3)

66 284

1.8 (1.3–2.2)

n

% (95% CI)

n

% (95% CI)

CI = confidence interval, EVI = early visual impairment, MVI = moderate visual impairment, PVA = presenting visual acuity, SVI = severe visual impairment, VA = visual acuity.

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Table 3. Principal causes of blindness, severe (SVI), moderate (MVI) and early (EVI) visual impairment.

Blindness

1. Refractive error 2. Aphakia uncorrected 3. Cataract untreated 4. Cataract surgical complications 5. Trachomatous corneal opacity 6. Nontrachomatous corneal opacity 7. Phthisis 8. Onchocerciasis 9. Glaucoma 10. Diabetic retinopathy 11. AMD 12. Other posterior segment disease 13. All other globe/CNS abnormalities Total

Severe VI

Moderate VI

Early VI

n

%

n

%

n

%

n

%

0 0 7 1 0 0 1 0 4 2 9 9 0 33

0.0 0.0 21.2 3.0 0.0 0.0 3.0 0.0 12.1 6.1 27.3 27.3 0.0 100.0

0 0 6 2 0 0 0 0 3 2 3 0 1 17

0.0 0.0 35.3 11.8 0.0 0.0 0.0 0.0 17.6 11.8 17.6 0.0 5.9 100.0

47 0 98 7 0 2 0 0 4 3 22 9 5 197

23.9 0.0 49.7 3.6 0.0 1.0 0.0 0.0 2.0 1.5 11.2 4.6 2.5 100.0

107 0 112 7 0 2 0 0 3 5 15 7 5 263

40.7 0.0 42.6 2.7 0.0 0.8 0.0 0.0 1.1 1.9 5.7 2.7 1.9 100.0

AMD = age-related macular degeneration, CNS = central nervous system.

reviewed each data form together with the doctors who filled them in, and in several cases, we contacted the patients, their family doctors or their ophthalmologists again. Based on this work and the new contacts, we were able to specify the diagnoses in 24 of the 25 cases. The highest prevalence is the myopic degeneration (six cases) and retinal detachment (six cases of which three are due to high myopia). Other causes were central or branch retinal vein occlusion (four cases), heredodegenerative retinal diseases (three cases), epiretinal membrane (two cases), retinitis pigmentosa (DPR; two cases) and anterior ischaemic optic neuropathy (AION) (one case). In one subject, we were not able to further specify the diagnosis, because no contact was available (nor with the patient nor with her doctors: family or ophthalmology).

Age (years)

Glasses and presbyopia

80+

3. 4. 7.

70–79

9. 10.

60–69

11. 12. 13.

50–59 0

5

10

15

20

25

30

%

Fig. 1. Principal cause of severe visual impairment and blindness in different age groups in the sample population. Numbers as listed in Table 3.

reduce avoidable blindness in Hungary are shown in Fig. 3. Cataract surgical coverage (CSC)

In Hungary – based on our sample results – 90.7% of all eyes which would be blind without cataract operation have been operated upon: 88.8% in males and 91.4% in females. Of all eyes with a BCVA < 6/60 due to cataract, 88.4% are operated upon; of the eyes with a BCVA < 6/18, 72.1% are operated upon, indicating that most eyes with SVI and MVI due to cataract require surgical intervention. Of all persons who would be bilaterally blind due to cataract, 96.2% are

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operated upon in one or both eyes: in males 94.3% and in females 97.0%. For BCVA < 6/60, the CSC is 94.2%, and for BCVA < 6/18, it is 81.1%. These values indicate that cataract surgery is well under control in Hungary and that services are used equally by men and women. Other posterior segment diseases

After finishing the fieldwork, we decided to review the 25 subjects with the diagnosis ‘Other posterior segment diseases’ (nine blind, 0 SVI, nine MVI, seven EVI), as this was one of the most frequent causes of blindness in Hungary’s 50+ population. We carefully

Among the examined participants 50 years of age or older, 44.0% were using distance glasses (37.4% in males and 47.7% in females) and 84.3% were using reading glasses (80.8% in males and 86.3% in females).

Discussion Hungarian data collection on newly registered blind people already started in the early 2000s and continued with new estimations in 2012 (Nemeth et al. 2005; Kiss & Nemeth 2013). However, no population-based epidemiological data were available to date. Ours was the first population-based survey on blindness and DR in Hungary, and also the first successful RAAB+DR study completed in an industrialized country worldwide according to our knowledge. An unexpectedly good response rate (95.9%) was achieved by making a huge effort to find the appropriate local helper in each cluster, which is indispensable for gaining representative data. A limitation of the study was that the age group 70–79 was over-represented, while the age group 50–59 was underrepresented in our sample compared to the actual population of Hungary, which means that the sample prevalence may be slightly higher compared to the age- and sex-adjusted prevalence. Another limitation of this study was defining the category group of the


Age (years)

1.

80+

3. 4.

70–79

6. 9. 10.

60–69

11. 12.

50–59

13. 0

10

20

30

40

50

60

70

%

Fig. 2. Principal cause of moderate visual impairment in different age groups in the sample population. Numbers as listed in Table 3.

1. Cataract surgery 2. PHC/PEC services

21.2%

3. Ophthalmic services 3.0%

4. Rehabilitaon/low vision

54.5% 21.2%

Fig. 3. Action required to reduce blindness and the need for rehabilitation. PEC = primary eye care, PHC = primary health care.

diagnosis named ‘other posterior segment disease’, as it was a major cause of blindness. Although RAAB originally intentionally focused on the major causes of blindness and visual impairment in the world, after reviewing these cases, we found that it would be a good idea for the future RAAB studies to expand the list of diagnoses with more posterior segment diseases – for example, pathologic myopia and retinal detachment. This would be of paramount importance in high-income countries, where these diseases are expected to be among the leading causes. However, adding further diagnoses may result in more detailed, time-consuming examinations and increased study costs. Prevalence of visual impairment and blindness

The prevalence of blindness varies worldwide: the age-standardized prevalence of blindness in adults aged

50 years or older was more than 4% in Western and Eastern Sub-Saharan Africa (6.0% and 5.7%), South Asia (4.4%), North Africa and the Middle East (4.6%, 3.5%–5.8%), in contrast to high-income regions with blindness prevalence of 0.4% or less (Stevens et al. 2013). The estimated prevalence of blindness in our study was lower (0.9%) than expected (1.2%), based on the earlier estimates of the WHO (Resnikoff et al. 2004), but higher than the prevalence found in high-income regions by Stevens et al. As the second European RAAB+DR study, it is essential to compare our results with the Moldovan study. The prevalence of blindness and all categories of visual impairment were lower in our country than in Moldova (blindness: 0.9 versus 1.4%, SVI: 0.5 versus 2.2%, MVI: 5.6 versus 13.0; Zatic et al. 2015). This could be due to the better Hungarian eye care

facilities and the fact that Hungary is a more economically developed country. Causes of visual impairment and blindness

While the leading causes were cataract in all subregions of Europe in the 1990s, AMD and uncorrected refractive error became the major causes of blindness in 2010 in all high-income countries, except for eastern and central Europe, where cataract remained the leading cause (Bourne et al. 2014). Based on these data, our findings demonstrate that the level of the Hungarian eye care services is slightly closer to western European eye care. While comparing with the results of other RAAB studies conducted across the world, the most remarkable difference was by the main cause of blindness: while cataract was the leading cause in lower- and middle-income countries (e.g. South America, Africa, the Middle East Region), AMD and other posterior segment diseases were the major causes in Hungary (Xiao et al. 2010; Rajavi et al. 2011; Al Ghamdi et al. 2012; Polack et al. 2012; Minderhoud et al. 2015; Rabiu et al. 2015). Nevertheless, visual impairment caused by cataract can be a serious public health problem not only in rural areas, but also in regions with established market economy (Cheng et al. 2016; Xu et al. 2016). In Moldova, untreated cataract was the leading cause of blindness with a prevalence of 58.2%, which is more than two times higher than our results (21.2%). In Moldova, this was followed by other posterior segment diseases and glaucoma (both with 10.9%). In comparison, our study has a higher prevalence of AMD (27.3% versus 5.5%) and other posterior segment diseases (27.3% versus 10.9%). These can be explained with the higher Hungarian CSC (96.2% versus 77.8% for BCVA < 3/60), the different socioeconomic status of the two countries and their different subregional location in Europe. Prevention of blindness

In our study, 45.5% of blindness, 76.5% of SVI, 81.7% of MVI and 89.7% of EVI were avoidable, which means that even in an industrialized country considerable reduction in avoidable blindness and visual impairment can be achieved by improving the

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coverage of eye health services and more focus on prevention. The high percentage of URE highlights the need for optimizing the optical services in Hungary. Blindness related to AMD and other posterior segment diseases can be prevented through regular ophthalmic control and timely intervention. It is essential to develop intensified specialized ophthalmic care and targeted health education. The high CSC (90.7%) indicates well-organized and controlled cataract surgical care in Hungary. Despite the high CSC for all visual impairment categories, cataract surgery is still one of the most important intervention strategies to reduce the prevalence of avoidable blindness. Demographic trends

Like all other countries in Europe, Hungary is also undergoing demographic changes. The population is ageing and declining. In numbers, the population in Hungary aged 50+ will increase from 3.32 million in 2000 to 4.28 million in 2030 (Bureau). Assuming that the blindness prevalence of 0.9%, of which 18% is caused by cataract (this national survey), remains the same for this entire period, then the number of people bilaterally blind from cataract in Hungary will increase by about 14% between 2015 and 2030. With economic improvements and increasing life expectation, the demand for good eyesight and cataract surgery at earlier stages by the public will also increase. The higher developed a society, the greater the demand for good eyesight. Altogether, the demand for eye care services in Hungary may well increase by a factor of 1.5–2.0 between 2000 and 2030. This RAAB study assesses the situation approximately halfway through that period and can provide us with good insight on how the eye care services in Hungary are responding to that increased demand. Cataract surgery should still remain a priority, especially the earlier cases. Because blindness and visual impairment due to posterior segment diseases such as AMD, glaucoma and DR might be prevented through regular control and timely intervention, targeted health education and the development of

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specialist ophthalmic services might be able to reduce avoidable blindness and visual impairment further.

Conclusion The RAAB+DR study in Hungary documented a low prevalence of blindness, with AMD and other posterior segment diseases being the major causes. Our study is the evidence that Hungary is on its way to achieve the goals of VISION 2020; however, cataract is still an important problem and the number of cataract operations per year will continue to increase to cover demographic changes and increased demand. Our results also demonstrate that the RAAB methodology can be successfully used in industrialized countries, even in higher-income European regions, which often lack reliable epidemiologic data.

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Received on October 27th, 2016. Accepted on June 26th, 2017. Correspondence: Janos Nemeth, MD, PhD, Dsc Department of Ophthalmology Semmelweis University 39 Maria str. Budapest 1085 Hungary Tel: +361 3039435 Fax: +361 3179061 Email: [email protected] This research project was made possible with a SightFirst research grant from the Lions Clubs International Foundation. We also like to thank the National Institute of the Blind, the Hungarian Lions Clubs, the Hungarian Central Statistical Office, the Hungarian Diabetes Society, and 77 Elektronika Co for their active support during the planning and implementation of this study. We also thank to Serge Resnikoff for his important comments. The results were partially presented as a poster in the ARVO 2016 Meeting in Seattle, USA. Ethics committee approval: The study was approved by Semmelweis University Regional and Institutional Committee of Science and Research Ethics. Competing interests statement: There are no competing interests.