case study on blind child in india

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School for Blind and Visually Impaired Children / SEAlab

• Curated by Hana Abdel
• Architects: SEAlab
• Area Area of this architecture project Area:  750 m²
• Year Completion year of this architecture project Year:  2021
• Photographs Photographs: Dhrupad Shukla , Lakshay Bansal , Anand Sonecha , Aakash Dave , Bhagat Odedara , Aneesh Devi
• Lead Architect: Anand Sonecha
• Landscape Architect:  Lokendra Balasaria
• Structure Engineer:  Bhailalbhai Gajjar
• Project Management:  Kshitij Gajjar
• Electrical And Plumbing Consultant:  Rakesh Modi
• Site Management:  Mitul Prajapati
• Contractor:  Vasant Prajapati
• City:  Gandhinagar
• Country:  India
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Text description provided by the architects. School for the blind and visually impaired children in Gandhinagar is designed for children from remote villages and towns in Gujarat and professors eager to offer them a better education and opportunities in society. Initially, the school occupied an existing building, previously a primary school. The 1st floor was used as classrooms for academic activities and the ground floor as dormitories. Earlier, there was less space for all the students (12 children shared in each dorm room) and no capacity to welcome more.

Design - The new academic building, on the west of the existing one, has ten classrooms with five different types arranged around a central courtyard. This space provides a contained exterior space for the children to play, perform, or celebrate festivals. This simple building typology allows the students to create a mental map of the spaces. The corners are identified with strokes of light or articulated volumes, and the corridor surrounding the central plaza has different widths and volumes on each side. This allows the students to identify their location in the building. Each classroom around the central plaza has different features for specific uses – music rooms, meeting spaces, workshops, etc. Based on their functions, the "special" classrooms have various forms, volumes, and light qualities. The other classrooms are like verandahs; each opens to a private courtyard with the possibility of outdoor learning. The relation with exterior spaces allows for better ventilation and controlled light quality.

The building is designed to be incremental or built-in phases according to the available funding. The classrooms are smaller cells plugged into the main spaces – the plaza and the corridor. The geometry of these classroom units creates a play of light and shadow and an efficient response to the hot climate. More than 1000 shrubs, plants, and trees of 37 species are planted on campus to provide shade and fruits, invite butterflies and birds, and diversify and improve the natural environment. Khambhati Kuva (Percolation well) – a traditional rainwater harvesting technique of 10ft diameter and 30ft depth was built to collect the rainwater and the recharge ground. The well can absorb 45,000 to 60,000 liters of water in one hour.

This school is designed to be navigated with the help of more than one of the five senses:

Sight - Many students have low vision; they can distinguish spaces that have the contrast of light and shadow or contrasting colors and surfaces. Specific skylights and openings are designed to create contrasting areas with light and shade. For example, the entrance vestibule of the special classrooms is marked by a high ceiling with a skylight making a flare of light. Also, contrasting colors are used on the doors, furniture, and switchboards so that the students can easily differentiate the elements during navigation. Since the students with low vision are sensitive to direct sunlight, the classroom has indirect, filtered light from the private courtyards and skylights.

Hearing - The sound of the voice or the walking steps changes according to the echo produced in the spaces. The design attributes different heights and widths to areas of corridors and classrooms so that children can recognize them by sound. For example, the entrance corridor has a high ceiling height (3.66m), and it gradually reduces in height (2.26m) and width, giving an identifiable sound quality to each space.

Smell - The landscape has a significant role in the design. Courtyards, located next to the classroom and connected to the corridor, have aromatic plants and trees, which help in the navigation of the building.

Touch - The material and textures of the walls and floor, with smooth and rough surfaces, guide the students throughout the spaces.

Floor : Kota stone is the principal material used for the flooring. Rough Kota stone marks the entrance to each classroom, whereas the other spaces have smooth Kota stone. While navigating, this change in textures guides the students.

Walls : There are five different wall plaster textures used in the building. The two longer sides of the corridor have horizontal textures, whereas the shorter side has vertical textures. This helps students identify which sides of the corridor they are navigating. The central courtyard has a semi-circular texture, whereas the external surface of the overall building is sand-faced plaster.

User engagement approach - For the Schools design, there was a need to reinvent communication and participation tools. We had multiple meetings at different stages of the process to engage the students and teachers on the design. Initially, we relied on cardboard models to start a conversation with students and teachers. They could visualize the built form through touch, but soon, we realized it wasn't easy to comprehend the interior spaces and details. To counter the issue, we developed communication techniques using a 3d printer. This allowed for the construction of tactile drawings and robust models that the students could touch and visualize spaces. We developed a code of textures to communicate the design to students and teachers. These textures overlapped the plan and helped to visualize the architectural spaces. The interior spaces had a different texture than the exterior, just like circulation spaces or classrooms. Moreover, each area (classroom, corridor, courtyard) was marked and written in Braille.

3d printed detailed models were also part of the communication strategy. It enabled students to touch them without breaking them. They had details like furniture and people to help understand the spaces' organization and scale. Before the construction, we did a full-scale line-up on the site. All trustees, professors, and some students circulated throughout the space and gave their feedback. Lastly, during the construction, the contractor built mock-ups of some techniques that could help the students to navigate the building. For example, some of the students tried different wall plaster textures to clarify their effectiveness.

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Project location

Address: gandhinagar, gujarat, india.

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Open Access

Peer-reviewed

Research Article

Blindness and visual impairment and their causes in India: Results of a nationally representative survey

Roles Conceptualization, Data curation, Formal analysis, Funding acquisition, Investigation, Methodology, Project administration, Resources, Software, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing

* E-mail: [email protected]

Affiliation Community Ophthalmology, Dr. R P Centre, AIIMS, New Delhi, India

Roles Conceptualization, Data curation, Methodology, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing

Roles Data curation, Formal analysis, Investigation, Methodology, Software, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing

Roles Investigation, Methodology, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing

Affiliation Ophthalmology, Dr. R P Centre, AIIMS, New Delhi, India

Roles Data curation, Formal analysis, Resources, Software, Supervision, Validation

Affiliation School of Medical Sciences, University of Hyderabad, Hyderabad, Telangana

Roles Data curation, Investigation, Methodology, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing

Affiliation Chacha Nehru Bal Chikitsalaya, New Delhi, India

Roles Data curation, Formal analysis, Investigation, Methodology, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing

Affiliation Institute Rotary Cancer Hospital, AIIMS, New Delhi, India

Roles Visualization, Writing – original draft, Writing – review & editing

Roles Writing – original draft

Roles Methodology, Project administration, Resources, Supervision, Validation, Visualization

Affiliation AIIMS, New Delhi, India

• Praveen Vashist, 
• Suraj Singh Senjam, 
• Vivek Gupta, 
• Noopur Gupta, 
• B. R. Shamanna, 
• Meenakshi Wadhwani, 
• Pallavi Shukla, 
• Souvik Manna, 
• Saumya Yadav, 
• Amit Bharadwaj

• Published: July 21, 2022
• https://doi.org/10.1371/journal.pone.0271736
• Reader Comments

Introduction

Avoidable blindness is a significant public health problem in India. Nationally representative RAAB surveys (Rapid Assessment of Avoidable Blindness) are being conducted periodically in the country to know the current status of blindness in the country. The current study describes the findings from the RAAB survey conducted during 2015–19 in India.

Methodology

A cross-sectional, population-based survey was conducted across the entire country among persons aged 50 years and above using RAAB version 6 methodology. Presenting and pinhole visual acuity was recorded followed by lens examination using a torchlight. In order to estimate the prevalence of blindness and visual impairment in overall population in India, district weights were assigned to each of the 31 surveyed districts and the prevalence was standardized using the RAAB software.

The overall weighted, age-gender standardized, prevalence of blindness (presenting visual acuity <3/60 in better eye) in population aged ≥50 years was 1.99% (95% CI 1.94%, 2.13%) and of visual impairment (VI) (presenting visual acuity <6/12 in better eye) was 26.68% (95% CI 26.57–27.17%). On multivariate analysis, adjusted odds ratio showed that blindness was associated with age ≥ 80 years (OR = 20.3, 95% CI: 15.6–26.4) and being illiterate (OR = 5.6, 95% CI: 3.6–8.9). Blindness was not found to be significantly associated with either gender or locality.

The results of the survey demonstrate that currently more than one fourth of persons aged 50 years and above are visually impaired (PVA<6/12 in better eye) in India. The prevalence of blindness among them is 1.99%, and older age and illiteracy are significantly associated with blindness. Major causes of blindness included cataract (66.2%), corneal opacity (CO) (8.2%), cataract surgical complications (7.2%), posterior segment disorders (5.9%) and glaucoma (5.5%). The proportion of blindness and visual impairment that is due to avoidable causes include 92.9% and 97.4% respectively.

Citation: Vashist P, Senjam SS, Gupta V, Gupta N, Shamanna BR, Wadhwani M, et al. (2022) Blindness and visual impairment and their causes in India: Results of a nationally representative survey. PLoS ONE 17(7): e0271736. https://doi.org/10.1371/journal.pone.0271736

Editor: Timo Eppig, Saarland University, GERMANY

Received: January 8, 2022; Accepted: July 6, 2022; Published: July 21, 2022

Copyright: © 2022 Vashist et al. This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: The data underlying the results presented in the study are available from DOI: https://doi.org/10.6084/m9.figshare.19785382.v1 .

Funding: The survey was funded by the National Programme for Control of Blindness and Visual Impairment, Ministry of Health and Family Welfare, Government of India. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

Globally, at least 2.2 billion people have a vision impairment, and of these, at least 1 billion people have a vision impairment that could have been prevented or is yet to be addressed [ 1 ]. The definitions of blindness have evolved over the years internationally and in India [ 2 ]. A contemporary blindness study from Central Europe defined blindness as visual acuity ≤ 1/60 without visual field defects, as visual acuity ≤ 2/60 with quadrantanopsia, as visual acuity ≤ 4/60 with hemianopsia, or as visual acuity 6/60 with tunnel vision [ 3 ]. Similarly, it defined visual impairment as visual acuity ≤ 3/60 without visual field defects, as visual acuity 6/60 with quadrantanopsia, as visual acuity 6/20 with hemianopsia, or as visual acuity ≤ 6/6 with tunnel vision. The WHO definition of blindness, used in the current study, is slightly less strict than the definition used in Europe and defines a presenting visual acuity (PVA) of 3/60 or worse as indicating blindness; and PVA <6/12 as visual impairment [ 4 ]. Blindness is a significant public health problem globally with a disproportionately large prevalence in low and middle income countries (LMICs) [ 5 ]. Various efforts have been made at the global level to address this situation. In 2013, the World Health Assembly launched Global Action Plan (WHA GAP) with a target of achieving 25% reduction in prevalence of avoidable visual impairment by 2019 compared to the baseline levels of 2010 [ 6 ]. Recent reports by Vision Loss Expert Group (VLEG) of the Global Burden of Disease (GBD) Study show that there are approximately 33.6 million blind people and 206 million people with moderate to severe visual impairment globally [ 7 ]. Although, there is a decline in the prevalence of avoidable visual impairment, especially in adults aged 50 years and above, the WHA GAP target has not been met [ 7 ].

India has implemented a series of effective measures in its ongoing National Program for Control of Blindness and Visual Impairment (NPCB&VI) to combat the situation, and it has resulted in a significant decline in prevalence of blindness over the past few decades [ 8 , 9 ]. Periodic updates in current estimates and causes of blindness and visual impairment are essential to assess the effectiveness of ongoing public health policies and provide a sound basis for development of future strategies and their effective implementation. The Rapid Assessment of Avoidable Blindness (RAAB) has been developed as a simple and rapid survey methodology that can provide data on the prevalence and causes of blindness [ 10 ]. RAAB was developed by Hans Limburg working with the International Centre for Eye Health, first as the Rapid Assessment of Cataract Surgical Services in 1997, and then updated and modified to create RAAB in 2004 [ 11 – 13 ].

Currently, various methods are in use for rapid assessment of visual impairment, but largely these methods are used for older adults (50 years and above), including RAAB [ 14 ]. The current study was a nationwide RAAB survey conducted in randomly selected 31 districts of India with the assistance of NPCB&VI, India. The objective was to document the status of blindness and provide evidence-based data on the prevalence and determinants of blindness and visual impairment in population aged ≥50 years in the country. The findings of the survey will also help in monitoring the trend of blindness over time for programmatic purpose.

This was a cross-sectional, population-based survey conducted across the entire country during 2015–19 among population aged 50 years and above. The survey protocol was approved by the Institute Ethics Committee, All India Institute of Medical Sciences, New Delhi, India. Approvals from state and district health authorities were obtained before initiating survey activities and the study was conducted as per the tenets of the Declaration of Helsinki. Written informed consent was obtained from every participant and any participant requiring ophthalmic care was offered referral services to the nearest eye care centre.

The Rapid Assessment of Avoidable Blindness (RAAB) version 6 methodology was utilized, which used paper-based data collection and Snellen E optotypes for visual acuity. The RAAB subsequently launched version 7 in 2021 which facilitated greater use of mobile technologies and a greater emphasis on using the data for planning [ 15 ]. Eligible Subjects included population aged 50 years and above residing in the selected household for the past six months or more. “Residing in household” was defined as sharing meals from the same kitchen with other household members.

Sample size and sampling

The survey was designed to be representative of the entire country. The sampling frame comprised of all the 631 districts of India as per the 2011 census and 31 districts were randomly selected using probability proportionate to size (PPS) systematic random sampling. Based on 3.6% estimated prevalence of blindness, 25% relative precision, 95% confidence interval, design effect of 1.6, and coverage of 90%, sample size for each district was calculated as 3000 [ 6 ]. Within each district, 50 clusters were again selected using PPS sampling. Within a selected cluster, compact segment sampling was utilized by the field team using draw of chits. Within the selected segment, households were selected from a random starting point, and a line listing was done, till the sample size of 60 per cluster was achieved. This survey also included a module to assess diabetic retinopathy (DR) in selected districts having a high prevalence of diabetes, the results of which are published already [ 16 ]. The 50 clusters included a representative proportion of rural areas (villages) and urban wards, based on the rural-urban distribution of the district population. An urban area, according to the Census definition, consists of [ 17 ]:

• all statutory towns: All places with a municipality, corporation, Cantonment Board or notified town area committee, etc. so declared by state law.
• Census towns: Places with a minimum population of 5000, at least 75 percent of male working population engaged in non- agricultural pursuits and a density of population of at least 400 persons per square km.

In addition, some areas falling in the vicinity of city or town are also considered as urban area if they are treated as the out growths (OGs) of the main urban unit. Such OGs are shown as urban agglomerations. As per the census definition, urban agglomeration is a continuous urban spread constituting a town and its adjoining urban outgrowths (OGs) or two or more physical contiguous town together and any adjoining urban out growths of such towns. All remaining areas which are not urban are classified as rural, and the basic unit for rural areas is the revenue village.

Clinical assessment.

Clinical examination of study participants aged 50 years and above was performed as per RAAB version 6 methodology. Age, gender, and educational status of each participant were documented and presenting visual acuity (PVA) was assessed using Snellen `E’ optotypes sized 6/12, 6/18 and 6/60, starting with the largest size from a distance of 6 metres. Pinhole visual acuity was assessed in case the PVA was less than 6/12 in order to identify refractive errors. Assessment of anterior segment and lens status was done using a portable slit lamp and distant direct ophthalmoscopy. In case of vision loss with no apparent anterior segment cause, dilated fundus evaluation was done using direct and/or indirect ophthalmoscope. The ophthalmologist noted the principal cause of visual impairment for any eye if the presenting visual acuity was less than 6/12, and the principal cause for the participant was taken as that in the better eye. Only one diagnosis was marked for each eye and one diagnosis for the participant. In case there were two or more co-existing primary conditions in one eye, the more avoidable/treatable cause was marked as the principal cause.

Prior to initiation of the RAAB survey, the entire team was trained and certified in the RAAB methodology by an accredited RAAB trainer as per the survey protocol. Before undertaking the RAAB survey, inter-observer variation (IOV) test among optometrists was performed for presenting and pinhole vision examination in each eye. For ophthalmologists, IOV test was done to measure agreement on the assessment of lens status in each eye and cause of visual impairment in each eye and also in the participant. The findings of each ophthalmologist were compared with the findings of the most experienced ophthalmologist, the so-called ‘Gold Standard’. The RAAB package module was used to calculate the IOV, which was expressed in the Kappa coefficient. Any team scoring a Kappa of less than 0.60 was trained again before participation in the fieldwork. A standardized manual of operations was developed for the survey.

Data analysis

The data was entered in RAAB-6 software package (50+ survey) on the same day that the survey was conducted. Transcription errors were minimized through dual-data entry and double data entry validation. The corrected dataset was analysed using inbuilt routines and validation checks of the RAAB6 software. Standardized definitions were used for classifying participants’ visual status and diagnosis. ( Table 1 ) Data within each district was directly age-sex standardized by the in-built analysis routines of RAAB-6, using the age-sex distribution of the 2011 national census population. In order to calculate the district weights, the population that was aged 50 years and above in each of the sampled districts was divided by the total population that was aged 50 years and above in all 31 sampled districts. Subsequently, country-level estimates were obtained by multiplying the age-sex standardized prevalence with the respective district weights and taking the cumulative sum of all 31 districts. Calculations were done separately for male and female population, and also for combined population. The data was exported as comma separated files for univariate and multivariate analysis using Stata (StataCorp, College Station, Texas). For all point estimates, 95% confidence intervals were calculated, and the critical significance value was fixed as p value < 0.05.

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https://doi.org/10.1371/journal.pone.0271736.t001

Overall, 93018 individuals (≥ 50 years of age) were enumerated from 31 districts, out of which 85135 completed all study procedures and ophthalmic assessment (participation rate 91.5%). A higher participation was observed in females (94.9%) in comparison to males (87.4%). Mean age of the study participants was 61.6 (±9.6) years (range, 50–99 years) and 57.3% of the participants were females. Mean age of males was 62.4 (±9.5) years (range, 50–99 years) and that of females was 61 (±9.5) years (range, 50–99 years). There was no significant difference between age and gender of the participants and non-participants. Overall, 66,304 (77.9%) participants resided in rural areas and 57.6% were illiterate ( Table 2 ).

https://doi.org/10.1371/journal.pone.0271736.t002

The overall age-gender standardized prevalence of blindness in population aged ≥50 years was 1.99% (95% CI 1.94%, 2.13%) ( Table 3 ). A rising trend in prevalence of blindness was noted with increasing age of the participants. The prevalence increased from 0.45% (95% CI: 0.4–0.5%) in 50–59 years to 4.11% (95% CI: 3.8–4.5%) in 70–79 years and 11.62% (95% CI 10.7–12.6%) in those aged ≥80 years. A higher prevalence was noted in females (2.31%, 95% CI: 2.18–2.45%) than in males (1.67%, 95% CI: 1.54–1.81%). Participants residing in rural regions had higher prevalence of blindness (2.14%, 95% CI: 1.72–2.47%) than those living in urban regions (1.80%, 95% CI: 1.52–2.15%). Prevalence of visual impairment (VI) was 26.68% (95% CI 26.57–27.17%), showing similar trends with age, gender and place of residence ( Table 3 ), as was seen with blindness.

https://doi.org/10.1371/journal.pone.0271736.t003

Among the 31 surveyed districts, the highest prevalence was seen in Bijnor, Uttar Pradesh (3.7%: 2.9–4.4), whereas the lowest was seen in Thrissur, Kerala (1.1%: 0.6–1.5) ( Fig 1 ). Prevalence of blindness was higher among females than males in all districts except Khera (Gujarat), Birbhum (West Bengal) and Kadapa (Andhra Pradesh) where prevalence among males was higher. In Warangal (Telangana) there was equal prevalence among males and females.

https://doi.org/10.1371/journal.pone.0271736.g001

On multivariate analysis, adjusted odds ratio showed that blindness was associated with age more than 80 years (OR = 20.3, 95% CI: 15.6–26.4) and being illiterate (OR = 5.6, 95% CI: 3.6–8.9) ( Table 4 ). Those aged 80 years and above had about twenty times higher risk of becoming blind than those aged 50–59 years (p<0.001). Participants who were illiterate had nearly six times higher odds of being blind than those who were educated (10 th class and above) (p<0.001). Major causes of blindness included cataract (66.2%), corneal opacity (CO) (8.2%), cataract surgical complications (7.2%), posterior segment disorders (5.9%) and glaucoma (5.5%) ( Fig 2A ). Untreated cataract (48.01%) followed by uncorrected refractive errors (41.53%) were the major contributors to visual impairment ( Fig 2B ). Out of all the individuals examined, 11.5% had uncorrected refractive error and 74.2% had uncorrected presbyopia.

https://doi.org/10.1371/journal.pone.0271736.g002

https://doi.org/10.1371/journal.pone.0271736.t004

The proportion of avoidable blindness and avoidable visual impairment in the current study was 92.9% and 97.4% respectively. Among avoidable causes of blindness and VI, treatable causes were 68.1% and 90.4% respectively ( Fig 3A and 3B ).

https://doi.org/10.1371/journal.pone.0271736.g003

The study was conducted in 31 districts of India in active partnership with ophthalmology departments of medical colleges, non-governmental organizations (NGOs), “Vision 2020: The Right to Sight” partners and Regional Institutes of Ophthalmology (RIOs), depending on the location of the clusters. Concerted efforts have been made in the last few decades to eliminate avoidable causes of blindness and visual impairment in India. Nationally representative surveys have been conducted at periodic intervals to assist NPCB&VI in assessing the impact of ongoing eye care services. The last representative survey on blindness in India was conducted in 2006–07 using RAAB protocol among individuals aged 50 years and above [ 9 ]. RAAB surveys form the key source of data on visual impairment and blindness from LMICs [ 18 ]. They use a rapid method of examination and random cluster selection, are less expensive and utilize a standardized methodology that enables valid comparisons across countries and regions [ 13 , 19 ]. The RAAB surveys conducted in other South Asian countries like Thailand and Malaysia have been able to provide estimates at the country level only [ 20 , 21 ]. The approach adopted in the current survey enabled us to generate both district and country level estimates. By accounting for differences in population sizes and gender structures of sampled districts, the survey results are likely to be more valid.

In the population aged 50 years and above, the prevalence of blindness has remarkably declined over past two decades from 5.3% in 2001 to 3.60% in 2007 to 1.99% in the current survey [ 8 , 9 ]. Similarly, the prevalence of MSVI (PVA<6/18 to 3/60) in this group has reduced from 24.85% in 2001 to 16.8% in 2007 to 11.77% in the current survey [ 8 , 9 ]. For the year 2010, Malhotra et al, in their meta-analysis, also demonstrated similar favourable trend [ 22 ]. Inequity in access to preventive and curative eye care services may explain a higher prevalence of blindness in female, elderly and illiterate participants.

Untreated cataract continues to be the most common cause of blindness and VI in adults aged 50 years or more despite nearly 6.5 million cataract surgeries conducted in India with an average cataract surgical rate of nearly 5000 per million population per year [ 23 ]. Socioeconomic development and better health care provisions in the recent years has increased the life expectancy and hence the proportion of ageing population in the country. Irrespective of socio-economic status, the non-communicable diseases (NCDs), including blindness, requiring large quantum of health and social care are extremely common in old age [ 24 ]. Corneal opacity emerged as the second most common cause of blindness in this survey. Majority of the avoidable blindness burden due to CO was attributed to non-trachomatous causes and this emphasises the need of strengthening preventive strategies and eye banking services in the country. Proportion of visual impairment due to uncorrected refractive error has reduced considerably compared to previous studies [ 25 ]. Adoption of intraocular lens implantation as a routine practice following cataract surgery has decreased visual impairment due to uncorrected aphakia but at the same time an increase in visual impairment due to cataract surgical complications was observed. Effective surgical techniques and a skilled cataract surgeon are essential for successful outcome following cataract surgery [ 26 ]. Along with increasing the coverage of eye care services, delivery of a standard quality of care needs to be ensured. Other lesser important causes of blindness included posterior segment disorders and glaucoma. These two latter causes assume greater significance in the more industrialized nations, as reported by a blindness study from Central Europe [ 3 ].

The last nationally representative data on blindness in population aged 0–49 years was collected in 1986–89 Survey of Blindness in India [ 8 , 9 ]. In subsequent surveys, various assumptions were made to generate and extrapolate data to all age groups at the national level. India has a relatively younger population with about 83% of the population under 50 years of age [ 27 ]. Causes of blindness affecting this age group pose further threat as it affects the future productive force of the country. In a recent survey conducted among 0–49 years age group by NPCB&VI, Government of India, the prevalence of blindness and visual impairment reported in the 0–49 years age group was 0.52/thousand and 15.38/thousand respectively [ 28 ]. Using these proportions, the country-wide prevalence of blindness and visual impairment was estimated to be 0.36% and 5.47% respectively ( Table 5 ). The extrapolated number of blind and visually impaired in overall population for the year 2017 was estimated to be 4.8 million and 74.0 million respectively based on population projections [ 29 ].

https://doi.org/10.1371/journal.pone.0271736.t005

The WHO Global Action Plan for Universal Eye Health 2014–2019 targets a reduction in the prevalence of Avoidable Visual Impairment (previously defined as presenting visual acuity less than 6/18 in better eye) by 25% by the year 2019 from the baseline level of 2010. The WHO estimated a prevalence of blindness and VI as 0.68% and 5.30% respectively in India for the year 2010. The current survey shows a reduction by 47.1% in blindness and 51.9% in VI compared to the baseline levels. The target of 25% reduction in visual impairment has been successfully achieved by India ( Fig 4 ). However, for planning and local actions, disaggregated data per district will be needed to assist in programmatic interventions and prioritization. However, it is also noted that global estimates reported that the GAP target was not met and that ageing populations and the strong association between vision impairment and age were an important barrier in reaching the target [ 30 ].

https://doi.org/10.1371/journal.pone.0271736.g004

The avoidable causes of blindness include treatable causes (refractive error, aphakia uncorrected, cataract uncorrected) and preventable causes. The preventable causes include those preventable by primary health care/primary eye care (PHC/PEC) services like trachomatous corneal opacity, non-trachomatous corneal opacity, phthisis as well as those preventable by ophthalmic services like cataract surgical complications, glaucoma and diabetic retinopathy. The unavoidable causes include age related macular degeneration (ARMD), posterior segment diseases and globe/central nervous system (CNS) abnormalities. In the current study, the proportion of blindness and visual impairment due to avoidable causes was 92.9% and 97.4% respectively. According to WHO, blindness is curable or preventable in approximately 80% of cases [ 31 ]. The Global Burden Of Disease Study had reported that blindness due to cataract and under-corrected refractive error encompasses 50% of all global blindness in 2020 [ 30 ]. However, previous studies from the Indian sub-continent had reported avoidable blindness ranging from 80–95%, with wide geographical disparities [ 9 , 32 – 35 ]. A survey on DR was also conducted in twenty-one districts out of the thirty-one covered in the current survey, in which the prevalence of DR among persons with diabetes was 16.9%, prevalence of STDR was 3.6%, and that of mild retinopathy was 11.8% [ 16 ]. This highlights the pressing need of targeting the avoidable causes in the country, which can be easily treated or prevented.

There remain several districts in India, with little or no population-based data where estimates rely on extrapolation from other regions. The findings of the current study spanning thirty-one districts out of 641 does not provide the status of blindness in the remaining districts. Only state and national level estimates can be deduced. Furthermore, RAAB is not a detailed blindness survey: it provides a reasonably accurate estimate of the prevalence of blindness, and the proportion that is avoidable in a geographic area. RAAB is not designed to give accurate estimates of the prevalence of specific diseases. The estimates for causes of blindness are biased towards more avoidable causes, especially cataract. The small numbers of people found to be blind in the survey means that extrapolations and sub-group analyses has wide confidence limits. The absence of specialised diagnostic equipment meant that cases of posterior segment disease such as glaucoma and age-related macular degeneration were identified by clinical examination only which meant that results for posterior segment causes of blindness must be interpreted with caution.

The present study shows that India has made significant strides towards elimination of avoidable blindness. The prevalence of blindness and visual impairment has reduced significantly since the last national survey. However, the problem still poses a significant challenge in achieving universal eye health and needs a comprehensive and dedicated approach to effectively tackle the situation. In particular, focus is required to improve the eye banking and corneal transplantation services and cataract surgical practices in the country and to integrate refractive services effectively in the existing eye care system.

Supporting information

https://doi.org/10.1371/journal.pone.0271736.s001

Acknowledgments

RAAB India Study group (Prof. Atul Kumar, Ex-Chief, Dr. R.P. Centre, AIIMS, New Delhi, Dr. Promila Gupta, Ex-Principal Consultant, MoHFW, GOI, Prof. R.M. Pandey, HOD, Bio-Statistics Department, AIIMS, New Delhi, Dr. R.S. Dhaliwal, Scientist ’G’ & Head (NCD), ICMR, New Delhi, Dr. V. Rajshekhar, Assistant Commissioner, MoHFW, GOI, Prof. Jagat Ram, PGIMER, Chandigarh, Dr. Arvind Morya, AIIMS, Jodhpur, Dr. B.K. Jain, SSNC, Chitrakoot, Prof. R.R. Sukul, Aligarh Muslim University, Dr. Vishnu Jobanputra, S.S.N.C, Anandpur, Dr. Mehul Shah & Dr. Shriya Shah, Drishti Netralya, Dahod, Dr. Deepshikha Agarwal, MGM Eye Institute Raipur, Dr. Bibhuti Sinha & Dr. Anita Ambastha, IGIMS, Patna, Dr. Asim Sil, VMANNN, Haldia, West Bengal, Dr. BNR Subudhi, MKCG Medical College, Berhampur, Odisha, Dr. Monika Hora, Purnima Netralaya Jamshedpur, Dr. Uday Gajiwala & Dr. Rohan Chariwala, Divya Jyoti Trust, Surat, Gujarat, Col. Madan Deshpandey, H V Desai Hospital Pune, Dr. A.K. Shukla, MGIMS, Wardha, Dr. Pradeep Naik & Dr. Ugam Usgaonkar, Goa Medical College, Panaji, Dr. Dipali Deka, RIO Guwahati, Dr. Ching Sui Yumanam, RIMS Manipur, Dr. Taba Khanna, NPCB & VI, Arunachal Pradesh, Dr. K. Vishwanath, PVRI, Secunderabad, Dr. R.D. Ravindran, Aravind Eye Hospital Madurai, Mr. Bharath Subhramanium, Shankara Eye Foundation, Bengaluru, Dr. Thomas Cherian, Little Flower Hospital Angamaly, Dr. Talvir Sidhu, Research Officer, Community Ophthalmology, Dr. R.P. Centre, AIIMS, Dr. Parul Jain, Research Officer, Community Ophthalmology, Dr. R.P. Centre, AIIMS, Dr. Pranita Sahay, Senior Research Officer, Community Ophthalmology, Dr. R.P. Centre, AIIMS, Mr. Sumit Sharma, Programme Manager, Community Ophthalmology, Dr. R.P. Centre, AIIMS, Mr. Deepak Kumar, Computer Programmer, Community Ophthalmology, Dr. R.P. Centre, AIIMS, Mr. Rajesh Kumar Sharma, Statistician, Community Ophthalmology, Dr. R.P. Centre, AIIMS).

• 1. WHO. World report on vision. 2019. 180 p.
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• 6. World Health Organization (WHO). Universal eye health: A global action plan 2014–19. 2013.
• 17. Census of India 2011. Census of India 2011 Press Release: Rural—Urban distribution of Population (Provisional) Highlights [Internet]. PIB Release. 2011. p. 1–4. http://ridum.umanizales.edu.co:8080/jspui/bitstream/6789/377/4/Muñoz_Zapata_Adriana_Patricia_Artículo_2011.pdf .
• 27. Census of India: Age Structure And Marital Status [Internet]. [cited 2021 Dec 27]. https://censusindia.gov.in/census_and_you/age_structure_and_marital_status.aspx .
• 28. Vashist P, Singh SS, Gupta V, Gupta N, Rajshekhar V, Shamanna BR. National Blindness & Visual Impairment Survey 2015–19: A Summary Report. 2019. p. 1.
• 29. MoHFW. Population projections for India and states 2011–2036, Report of the technical group on populaton projections. 2019. p. 1–268.

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Carey Goldberg reports for NPR on Project Prakash, Prof. Pawan Sinha's non-profit that provides cataract operations for children in India. Sinha explains that by examining how a child reacts to gaining vision, “you have a ringside seat into the process of visual development.”

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Writing for The New Yorker , Patrick House examines Professor Pawan Sinha’s work with sight restoration. “A remarkable thing about the brain’s processing capabilities is that, even with less than perfect image quality, it can extract a great deal of meaning about the visual world,” says Sinha of the benefits of sight restoration surgery. 

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School for Blind and Visually Impaired Children by SEAlab

In India out of ten one student is suffering from permanent or partial blindness. The difficulty of this student is to adapt to this world in spite of their visual impairment to identify spaces on their own. This School in Gandhinagar a city in Gujarat in the northwest of India is done by SeaLab Studio , ‘School for Blind and Visually Impaired Children” is done especially for students in remote villages and teachers who are looking for an opportunity to help them educate. The school is completely an architectural experiment that incorporates materials, textures, and also human senses that play a major role in defining the spaces which incorporate touch, smell, hearing, and rays of vision. The density of each gave rise to each space and its adjoining areas. 

This structure is a play of light and shadow which adjoins different colours and their relevance. A lot of study has been done before executing the project. Initially, this was a primary school functioning in an existing building in which the 1st floor was used as classrooms and additional activities and the ground floor as dormitories which could only accommodate a few students (12 students had to share each dorm room). 

Anand wanted this design to be a solution for every student’s need, so to understand every need and complication he had to foresee he spent more time with kids.

Within The Walls  

The building, adorned with white walls and airy courtyards, is designed while navigating the four senses – smell, vision, touch, and sound. Keeping this in mind he incorporated materials, colour, and landscape accordingly. 

The new design of the School is centralised with a courtyard that allows children to play, perform, and for other activities, this courtyard is elongated into 10 classrooms connected with additional facilities, such as the music room and the meeting room whose functions determine their various shapes, sizes, and lighting qualities passages. 

Each classroom is connected to green pockets to facilitate enough greenery and also the volumes are defined to control the extreme heat of Gujarat. All these spaces are done with five types of plasters and textures such as the concrete with a semicircle motif on the walls of the inner court. This has been done to identify each space by touching the walls. Also, widths of heights range each passage.

Each classroom, courtyard, and passage in the school is marked and written in Braille on the walls. For another navigation, Anand made use of hearing and light intensity in passages because students will have difficulty with light so all the passages are filtered accordingly. 

Hearing – Also changing the volumes and heights of each room creates different echoes in different spaces this can also be used as another technique to identify the same. This has been achieved by making the entrance area long and wide and as we go inside the opposite edge being small and short. This contrast produces echoes inside the rooms and passages

Vision – Another element given importance is colour which can be used with students with lower vision. This has been achieved by making doors and furniture with different bright and vibrant colours for classrooms, toilets, etc. 

Smell – Additionally, to make more use of other techniques to differentiate spaces the architect also made use of the sense of smell by planting aromatic flowers growing in the small court connecting the classrooms and walkways and various areas of the entrance to understand the area more definitely.

Sustainable haven Along the walls

There are 5 special classrooms with 7 other classrooms with individual courtyards in the school. All the shapes of rooms and the planning and size of rooms have been executed in how the students would use them. All the furniture is arranged accordingly making it student-friendly and along with their needs and comfort.

Also the usage of various materials like Kota stone gives importance to locally available materials by distinguishing them with smooth and rough surfaces in different areas. as well as by planting more than 1000 plants of 37 different varieties.

A traditional rainwater harvesting well called Khambhati Kuva (Percolation well) has also been found underground. The well with a depth of 10 feet and a depth of 30 feet, is designed to collect rainwater and recharge the ground. This well can store 40,000 to 60,000 litres of water in an hour. 

Section showing roof lines of the School_©https://art4d.com/en/2022/09/school-for-blind-and-visually-impaired-children

There is more to this building apart from the architectural gimmicks, details, and execution. This can be a major example for future design to come by giving importance to all categories of people to satisfy their needs and comfort. Also, we can see the dedication of every person involved in this project and how its final product is executed finely giving importance to every fine detail of the design. 

 Citations:

Websites referred for data and information 

• https://volzero.com/articles/view/school-for-the-blind-and-visually-impaired-children-by-sealab 
• https://sea-lab.org/filter/sealab/updates-1
• https://art4d.com/en/2022/09/school-for-blind-and-visually-impaired-children
• https://www.thebetterindia.com/340084/gujarat-school-for-the-blind-and-visually-impaired-inclusive-design-architecture-by-anand-sonecha-sealabs/#google_vignette
• https://www.archdaily.com/984721/school-for-blind-and-visually-impaired-children-sealab

Devapriya is an architect from Kerala, a fresher who is trying to acknowledge her strength in different fields of architecture. An energetic soul more attached to history and emotions, being expressive and approachable is another quality that makes her indulge in platforms like writing, teaching, Also her love for tropical architecture and sustainable design approaches.

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Cases of blindness and visual impairment decline dramatically across India

Visual Stories

Anjana Reddy ,

Mar 4, 2024

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Numerous blind schools in India help visually impaired children reach out to the world. Check out the top blind schools in India.

Blind schools provide simple professional and adaptive training and a basis in academic subjects offered through alternative formats. Literature, for example, was being made accessible to blind students by imprinted roman letters. Many blind schools in India help impaired people reach out to the world in their way.

Top Blind Schools in India  

The first-ever special school for the blind in India was set up at Amritsar in 1887. During the later six decades, many special schools came up in different parts of the country. So, there were about 50 such schools at the time of attaining independence.

Blind children, for the most part, stayed in these institutions and received education along with some basic trades that later led them to some vocational rehabilitation. The following is a list of blind schools in India. Utmost of the schools provide both residential and day programs as well as outreach programs.

Sri Rakum School

Shree ramana maharishi academy for the blind, devnar foundation for blind, pune blind school, poonamallee blind school, national federation of blind india.

• Jyothi Seva for Blind Children

Patiala School for the Blind

Sri Rakum School for the Blind is located at Shri Krishna Temple Road, Indira Nagar 1st Stage, Stage 1, Indiranagar, Bengaluru, Karnataka.

Sri Rakum School for the Blind is a residential school for the visually impaired and for the sighted-under people. They are over two decades ancient and are constantly growing to accommodate more children.

This school focuses on education and the all-around development of the child. They believe in the principle of inclusion and full participation.

SRMAB is located at 3rd Cross Rd, 3rd Phase, J. P. Nagar, Bengaluru, Karnataka

SRMAB is the retiring creation of a group of visionaries. SRMAB was initiated with the motto "Service to Humanity is service to God" by Sri. T V Srinivasan.

While they wanted to understand the situation, they were encouraged by the simplicity and consideration of senior official Sri Ramana Maharshi and encouraged to take public action.

Devnar School is located in Mayur Marg, Begumpet, Hyderabad, Telangana.

Devnar School is now regarded as an excellent centre for challenging people in India where students want to reach higher levels of achievement.

Pune Blind School is located at Gandhi Bhavan Road, Kothrud, Pune, Maharashtra

At this school, they understand and include students with diversity, including physical, emotional, academic, cognitive, and social differences.

Blind School is located at Poonammallee High Road, Poonammallee, in Chennai, Tamil Nadu.

It believes in the comprehensive development of the students by balancing academics, extra-curricular activities, and sports in the state of art infrastructure within the campus.

The school compromises playgrounds for cricket, basketball, volleyball, table tennis, badminton, and other sports.

Anna Durai St, near Ambedkar Statue, Gandhi Nagar, Tambaram East, Anakaputhur, Chennai, Tamil Nadu.

The National Federation of the Blind knows that blindness is not the personality that defines you or your future. They often raise the expectations of blind people because low expectations create barriers between blind people and their dreams.

Jyothi Seva Home for Blind Children

Jyothi Seva Home for Blind Children is located at Venkateshpuram, 1st Main Road, 3rd Cross, Bengaluru, Karnataka.

The goal of Jyothi Seva Home for Blind Children is To care for the upbringing, education, and rehabilitation of visually impaired children.

And to help children who are blind/have a lot of disabilities, adults in Jyothi Seva live a useful and healthy life at home and later as experienced adults/specialists.

Patiala school for Blind is located in Sector 26, near Homoeopathic Medical College and Hospital, Chandigarh.

The institute creates an idea/purpose for integrating the visually impaired into the normal aspects of public life. It involves professionals and people with a missionary spirit to give their best to help them in their renewal.

All media authorities make a concerted effort to give these children the necessary opportunities to become independent and develop their full potential. The center also aims to inspire and instill in them enthusiasm and aspiration for a quality of life that can be compared to their full participation and guarantee equal opportunities.

Objectives of Blind Schools

Children with severe visual impairment may suffer from mental retardation, especially in cognitive and cognitive development. These children can have difficulty finding visual information and making an impression on people and things and what is happening in their environment.

These difficulties will prevent them from consolidating their cognitive knowledge into concepts.

They should get information about other sensory systems, e.g., audio, touch, touch details, etc., and the information obtained may need to be clearer. Blind schools in India focus on the following aspects:

• Deliver equal opportunities and academic experiences for blind children as those provided for sighted children
• Allow blind children and their families and friends to socialize in normal situations.
• Change the public behavior towards blindness.
• Provide a natural basis for adult life practices so that blind students may take their proper places as contributing members of altogether sectors of society.

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Blindness and visual impairment and their causes in India: Results of a nationally representative survey

Praveen vashist.

1 Community Ophthalmology, Dr. R P Centre, AIIMS, New Delhi, India

Suraj Singh Senjam

Vivek gupta, noopur gupta.

2 Ophthalmology, Dr. R P Centre, AIIMS, New Delhi, India

B. R. Shamanna

3 School of Medical Sciences, University of Hyderabad, Hyderabad, Telangana

Meenakshi Wadhwani

4 Chacha Nehru Bal Chikitsalaya, New Delhi, India

Pallavi Shukla

5 Institute Rotary Cancer Hospital, AIIMS, New Delhi, India

Souvik Manna

Saumya yadav, amit bharadwaj.

6 AIIMS, New Delhi, India

Associated Data

The data underlying the results presented in the study are available from DOI: https://doi.org/10.6084/m9.figshare.19785382.v1 .

Introduction

Avoidable blindness is a significant public health problem in India. Nationally representative RAAB surveys (Rapid Assessment of Avoidable Blindness) are being conducted periodically in the country to know the current status of blindness in the country. The current study describes the findings from the RAAB survey conducted during 2015–19 in India.

Methodology

A cross-sectional, population-based survey was conducted across the entire country among persons aged 50 years and above using RAAB version 6 methodology. Presenting and pinhole visual acuity was recorded followed by lens examination using a torchlight. In order to estimate the prevalence of blindness and visual impairment in overall population in India, district weights were assigned to each of the 31 surveyed districts and the prevalence was standardized using the RAAB software.

The overall weighted, age-gender standardized, prevalence of blindness (presenting visual acuity <3/60 in better eye) in population aged ≥50 years was 1.99% (95% CI 1.94%, 2.13%) and of visual impairment (VI) (presenting visual acuity <6/12 in better eye) was 26.68% (95% CI 26.57–27.17%). On multivariate analysis, adjusted odds ratio showed that blindness was associated with age ≥ 80 years (OR = 20.3, 95% CI: 15.6–26.4) and being illiterate (OR = 5.6, 95% CI: 3.6–8.9). Blindness was not found to be significantly associated with either gender or locality.

The results of the survey demonstrate that currently more than one fourth of persons aged 50 years and above are visually impaired (PVA<6/12 in better eye) in India. The prevalence of blindness among them is 1.99%, and older age and illiteracy are significantly associated with blindness. Major causes of blindness included cataract (66.2%), corneal opacity (CO) (8.2%), cataract surgical complications (7.2%), posterior segment disorders (5.9%) and glaucoma (5.5%). The proportion of blindness and visual impairment that is due to avoidable causes include 92.9% and 97.4% respectively.

Globally, at least 2.2 billion people have a vision impairment, and of these, at least 1 billion people have a vision impairment that could have been prevented or is yet to be addressed [ 1 ]. The definitions of blindness have evolved over the years internationally and in India [ 2 ]. A contemporary blindness study from Central Europe defined blindness as visual acuity ≤ 1/60 without visual field defects, as visual acuity ≤ 2/60 with quadrantanopsia, as visual acuity ≤ 4/60 with hemianopsia, or as visual acuity 6/60 with tunnel vision [ 3 ]. Similarly, it defined visual impairment as visual acuity ≤ 3/60 without visual field defects, as visual acuity 6/60 with quadrantanopsia, as visual acuity 6/20 with hemianopsia, or as visual acuity ≤ 6/6 with tunnel vision. The WHO definition of blindness, used in the current study, is slightly less strict than the definition used in Europe and defines a presenting visual acuity (PVA) of 3/60 or worse as indicating blindness; and PVA <6/12 as visual impairment [ 4 ]. Blindness is a significant public health problem globally with a disproportionately large prevalence in low and middle income countries (LMICs) [ 5 ]. Various efforts have been made at the global level to address this situation. In 2013, the World Health Assembly launched Global Action Plan (WHA GAP) with a target of achieving 25% reduction in prevalence of avoidable visual impairment by 2019 compared to the baseline levels of 2010 [ 6 ]. Recent reports by Vision Loss Expert Group (VLEG) of the Global Burden of Disease (GBD) Study show that there are approximately 33.6 million blind people and 206 million people with moderate to severe visual impairment globally [ 7 ]. Although, there is a decline in the prevalence of avoidable visual impairment, especially in adults aged 50 years and above, the WHA GAP target has not been met [ 7 ].

India has implemented a series of effective measures in its ongoing National Program for Control of Blindness and Visual Impairment (NPCB&VI) to combat the situation, and it has resulted in a significant decline in prevalence of blindness over the past few decades [ 8 , 9 ]. Periodic updates in current estimates and causes of blindness and visual impairment are essential to assess the effectiveness of ongoing public health policies and provide a sound basis for development of future strategies and their effective implementation. The Rapid Assessment of Avoidable Blindness (RAAB) has been developed as a simple and rapid survey methodology that can provide data on the prevalence and causes of blindness [ 10 ]. RAAB was developed by Hans Limburg working with the International Centre for Eye Health, first as the Rapid Assessment of Cataract Surgical Services in 1997, and then updated and modified to create RAAB in 2004 [ 11 – 13 ].

Currently, various methods are in use for rapid assessment of visual impairment, but largely these methods are used for older adults (50 years and above), including RAAB [ 14 ]. The current study was a nationwide RAAB survey conducted in randomly selected 31 districts of India with the assistance of NPCB&VI, India. The objective was to document the status of blindness and provide evidence-based data on the prevalence and determinants of blindness and visual impairment in population aged ≥50 years in the country. The findings of the survey will also help in monitoring the trend of blindness over time for programmatic purpose.

This was a cross-sectional, population-based survey conducted across the entire country during 2015–19 among population aged 50 years and above. The survey protocol was approved by the Institute Ethics Committee, All India Institute of Medical Sciences, New Delhi, India. Approvals from state and district health authorities were obtained before initiating survey activities and the study was conducted as per the tenets of the Declaration of Helsinki. Written informed consent was obtained from every participant and any participant requiring ophthalmic care was offered referral services to the nearest eye care centre.

The Rapid Assessment of Avoidable Blindness (RAAB) version 6 methodology was utilized, which used paper-based data collection and Snellen E optotypes for visual acuity. The RAAB subsequently launched version 7 in 2021 which facilitated greater use of mobile technologies and a greater emphasis on using the data for planning [ 15 ]. Eligible Subjects included population aged 50 years and above residing in the selected household for the past six months or more. “Residing in household” was defined as sharing meals from the same kitchen with other household members.

Sample size and sampling

The survey was designed to be representative of the entire country. The sampling frame comprised of all the 631 districts of India as per the 2011 census and 31 districts were randomly selected using probability proportionate to size (PPS) systematic random sampling. Based on 3.6% estimated prevalence of blindness, 25% relative precision, 95% confidence interval, design effect of 1.6, and coverage of 90%, sample size for each district was calculated as 3000 [ 6 ]. Within each district, 50 clusters were again selected using PPS sampling. Within a selected cluster, compact segment sampling was utilized by the field team using draw of chits. Within the selected segment, households were selected from a random starting point, and a line listing was done, till the sample size of 60 per cluster was achieved. This survey also included a module to assess diabetic retinopathy (DR) in selected districts having a high prevalence of diabetes, the results of which are published already [ 16 ]. The 50 clusters included a representative proportion of rural areas (villages) and urban wards, based on the rural-urban distribution of the district population. An urban area, according to the Census definition, consists of [ 17 ]:

• all statutory towns: All places with a municipality, corporation, Cantonment Board or notified town area committee, etc. so declared by state law.
• Census towns: Places with a minimum population of 5000, at least 75 percent of male working population engaged in non- agricultural pursuits and a density of population of at least 400 persons per square km.

In addition, some areas falling in the vicinity of city or town are also considered as urban area if they are treated as the out growths (OGs) of the main urban unit. Such OGs are shown as urban agglomerations. As per the census definition, urban agglomeration is a continuous urban spread constituting a town and its adjoining urban outgrowths (OGs) or two or more physical contiguous town together and any adjoining urban out growths of such towns. All remaining areas which are not urban are classified as rural, and the basic unit for rural areas is the revenue village.

Clinical assessment

Clinical examination of study participants aged 50 years and above was performed as per RAAB version 6 methodology. Age, gender, and educational status of each participant were documented and presenting visual acuity (PVA) was assessed using Snellen `E’ optotypes sized 6/12, 6/18 and 6/60, starting with the largest size from a distance of 6 metres. Pinhole visual acuity was assessed in case the PVA was less than 6/12 in order to identify refractive errors. Assessment of anterior segment and lens status was done using a portable slit lamp and distant direct ophthalmoscopy. In case of vision loss with no apparent anterior segment cause, dilated fundus evaluation was done using direct and/or indirect ophthalmoscope. The ophthalmologist noted the principal cause of visual impairment for any eye if the presenting visual acuity was less than 6/12, and the principal cause for the participant was taken as that in the better eye. Only one diagnosis was marked for each eye and one diagnosis for the participant. In case there were two or more co-existing primary conditions in one eye, the more avoidable/treatable cause was marked as the principal cause.

Prior to initiation of the RAAB survey, the entire team was trained and certified in the RAAB methodology by an accredited RAAB trainer as per the survey protocol. Before undertaking the RAAB survey, inter-observer variation (IOV) test among optometrists was performed for presenting and pinhole vision examination in each eye. For ophthalmologists, IOV test was done to measure agreement on the assessment of lens status in each eye and cause of visual impairment in each eye and also in the participant. The findings of each ophthalmologist were compared with the findings of the most experienced ophthalmologist, the so-called ‘Gold Standard’. The RAAB package module was used to calculate the IOV, which was expressed in the Kappa coefficient. Any team scoring a Kappa of less than 0.60 was trained again before participation in the fieldwork. A standardized manual of operations was developed for the survey.

Data analysis

The data was entered in RAAB-6 software package (50+ survey) on the same day that the survey was conducted. Transcription errors were minimized through dual-data entry and double data entry validation. The corrected dataset was analysed using inbuilt routines and validation checks of the RAAB6 software. Standardized definitions were used for classifying participants’ visual status and diagnosis. ( Table 1 ) Data within each district was directly age-sex standardized by the in-built analysis routines of RAAB-6, using the age-sex distribution of the 2011 national census population. In order to calculate the district weights, the population that was aged 50 years and above in each of the sampled districts was divided by the total population that was aged 50 years and above in all 31 sampled districts. Subsequently, country-level estimates were obtained by multiplying the age-sex standardized prevalence with the respective district weights and taking the cumulative sum of all 31 districts. Calculations were done separately for male and female population, and also for combined population. The data was exported as comma separated files for univariate and multivariate analysis using Stata (StataCorp, College Station, Texas). For all point estimates, 95% confidence intervals were calculated, and the critical significance value was fixed as p value < 0.05.

Overall, 93018 individuals (≥ 50 years of age) were enumerated from 31 districts, out of which 85135 completed all study procedures and ophthalmic assessment (participation rate 91.5%). A higher participation was observed in females (94.9%) in comparison to males (87.4%). Mean age of the study participants was 61.6 (±9.6) years (range, 50–99 years) and 57.3% of the participants were females. Mean age of males was 62.4 (±9.5) years (range, 50–99 years) and that of females was 61 (±9.5) years (range, 50–99 years). There was no significant difference between age and gender of the participants and non-participants. Overall, 66,304 (77.9%) participants resided in rural areas and 57.6% were illiterate ( Table 2 ).

The overall age-gender standardized prevalence of blindness in population aged ≥50 years was 1.99% (95% CI 1.94%, 2.13%) ( Table 3 ). A rising trend in prevalence of blindness was noted with increasing age of the participants. The prevalence increased from 0.45% (95% CI: 0.4–0.5%) in 50–59 years to 4.11% (95% CI: 3.8–4.5%) in 70–79 years and 11.62% (95% CI 10.7–12.6%) in those aged ≥80 years. A higher prevalence was noted in females (2.31%, 95% CI: 2.18–2.45%) than in males (1.67%, 95% CI: 1.54–1.81%). Participants residing in rural regions had higher prevalence of blindness (2.14%, 95% CI: 1.72–2.47%) than those living in urban regions (1.80%, 95% CI: 1.52–2.15%). Prevalence of visual impairment (VI) was 26.68% (95% CI 26.57–27.17%), showing similar trends with age, gender and place of residence ( Table 3 ), as was seen with blindness.

MSVI: moderate-severe visual impairment; VI: visual impairment.

Among the 31 surveyed districts, the highest prevalence was seen in Bijnor, Uttar Pradesh (3.7%: 2.9–4.4), whereas the lowest was seen in Thrissur, Kerala (1.1%: 0.6–1.5) ( Fig 1 ). Prevalence of blindness was higher among females than males in all districts except Khera (Gujarat), Birbhum (West Bengal) and Kadapa (Andhra Pradesh) where prevalence among males was higher. In Warangal (Telangana) there was equal prevalence among males and females.

On multivariate analysis, adjusted odds ratio showed that blindness was associated with age more than 80 years (OR = 20.3, 95% CI: 15.6–26.4) and being illiterate (OR = 5.6, 95% CI: 3.6–8.9) ( Table 4 ). Those aged 80 years and above had about twenty times higher risk of becoming blind than those aged 50–59 years (p<0.001). Participants who were illiterate had nearly six times higher odds of being blind than those who were educated (10 th class and above) (p<0.001). Major causes of blindness included cataract (66.2%), corneal opacity (CO) (8.2%), cataract surgical complications (7.2%), posterior segment disorders (5.9%) and glaucoma (5.5%) ( Fig 2A ). Untreated cataract (48.01%) followed by uncorrected refractive errors (41.53%) were the major contributors to visual impairment ( Fig 2B ). Out of all the individuals examined, 11.5% had uncorrected refractive error and 74.2% had uncorrected presbyopia.

The proportion of avoidable blindness and avoidable visual impairment in the current study was 92.9% and 97.4% respectively. Among avoidable causes of blindness and VI, treatable causes were 68.1% and 90.4% respectively ( Fig 3A and 3B ).

The study was conducted in 31 districts of India in active partnership with ophthalmology departments of medical colleges, non-governmental organizations (NGOs), “Vision 2020: The Right to Sight” partners and Regional Institutes of Ophthalmology (RIOs), depending on the location of the clusters. Concerted efforts have been made in the last few decades to eliminate avoidable causes of blindness and visual impairment in India. Nationally representative surveys have been conducted at periodic intervals to assist NPCB&VI in assessing the impact of ongoing eye care services. The last representative survey on blindness in India was conducted in 2006–07 using RAAB protocol among individuals aged 50 years and above [ 9 ]. RAAB surveys form the key source of data on visual impairment and blindness from LMICs [ 18 ]. They use a rapid method of examination and random cluster selection, are less expensive and utilize a standardized methodology that enables valid comparisons across countries and regions [ 13 , 19 ]. The RAAB surveys conducted in other South Asian countries like Thailand and Malaysia have been able to provide estimates at the country level only [ 20 , 21 ]. The approach adopted in the current survey enabled us to generate both district and country level estimates. By accounting for differences in population sizes and gender structures of sampled districts, the survey results are likely to be more valid.

In the population aged 50 years and above, the prevalence of blindness has remarkably declined over past two decades from 5.3% in 2001 to 3.60% in 2007 to 1.99% in the current survey [ 8 , 9 ]. Similarly, the prevalence of MSVI (PVA<6/18 to 3/60) in this group has reduced from 24.85% in 2001 to 16.8% in 2007 to 11.77% in the current survey [ 8 , 9 ]. For the year 2010, Malhotra et al, in their meta-analysis, also demonstrated similar favourable trend [ 22 ]. Inequity in access to preventive and curative eye care services may explain a higher prevalence of blindness in female, elderly and illiterate participants.

Untreated cataract continues to be the most common cause of blindness and VI in adults aged 50 years or more despite nearly 6.5 million cataract surgeries conducted in India with an average cataract surgical rate of nearly 5000 per million population per year [ 23 ]. Socioeconomic development and better health care provisions in the recent years has increased the life expectancy and hence the proportion of ageing population in the country. Irrespective of socio-economic status, the non-communicable diseases (NCDs), including blindness, requiring large quantum of health and social care are extremely common in old age [ 24 ]. Corneal opacity emerged as the second most common cause of blindness in this survey. Majority of the avoidable blindness burden due to CO was attributed to non-trachomatous causes and this emphasises the need of strengthening preventive strategies and eye banking services in the country. Proportion of visual impairment due to uncorrected refractive error has reduced considerably compared to previous studies [ 25 ]. Adoption of intraocular lens implantation as a routine practice following cataract surgery has decreased visual impairment due to uncorrected aphakia but at the same time an increase in visual impairment due to cataract surgical complications was observed. Effective surgical techniques and a skilled cataract surgeon are essential for successful outcome following cataract surgery [ 26 ]. Along with increasing the coverage of eye care services, delivery of a standard quality of care needs to be ensured. Other lesser important causes of blindness included posterior segment disorders and glaucoma. These two latter causes assume greater significance in the more industrialized nations, as reported by a blindness study from Central Europe [ 3 ].

The last nationally representative data on blindness in population aged 0–49 years was collected in 1986–89 Survey of Blindness in India [ 8 , 9 ]. In subsequent surveys, various assumptions were made to generate and extrapolate data to all age groups at the national level. India has a relatively younger population with about 83% of the population under 50 years of age [ 27 ]. Causes of blindness affecting this age group pose further threat as it affects the future productive force of the country. In a recent survey conducted among 0–49 years age group by NPCB&VI, Government of India, the prevalence of blindness and visual impairment reported in the 0–49 years age group was 0.52/thousand and 15.38/thousand respectively [ 28 ]. Using these proportions, the country-wide prevalence of blindness and visual impairment was estimated to be 0.36% and 5.47% respectively ( Table 5 ). The extrapolated number of blind and visually impaired in overall population for the year 2017 was estimated to be 4.8 million and 74.0 million respectively based on population projections [ 29 ].

The WHO Global Action Plan for Universal Eye Health 2014–2019 targets a reduction in the prevalence of Avoidable Visual Impairment (previously defined as presenting visual acuity less than 6/18 in better eye) by 25% by the year 2019 from the baseline level of 2010. The WHO estimated a prevalence of blindness and VI as 0.68% and 5.30% respectively in India for the year 2010. The current survey shows a reduction by 47.1% in blindness and 51.9% in VI compared to the baseline levels. The target of 25% reduction in visual impairment has been successfully achieved by India ( Fig 4 ). However, for planning and local actions, disaggregated data per district will be needed to assist in programmatic interventions and prioritization. However, it is also noted that global estimates reported that the GAP target was not met and that ageing populations and the strong association between vision impairment and age were an important barrier in reaching the target [ 30 ].

The avoidable causes of blindness include treatable causes (refractive error, aphakia uncorrected, cataract uncorrected) and preventable causes. The preventable causes include those preventable by primary health care/primary eye care (PHC/PEC) services like trachomatous corneal opacity, non-trachomatous corneal opacity, phthisis as well as those preventable by ophthalmic services like cataract surgical complications, glaucoma and diabetic retinopathy. The unavoidable causes include age related macular degeneration (ARMD), posterior segment diseases and globe/central nervous system (CNS) abnormalities. In the current study, the proportion of blindness and visual impairment due to avoidable causes was 92.9% and 97.4% respectively. According to WHO, blindness is curable or preventable in approximately 80% of cases [ 31 ]. The Global Burden Of Disease Study had reported that blindness due to cataract and under-corrected refractive error encompasses 50% of all global blindness in 2020 [ 30 ]. However, previous studies from the Indian sub-continent had reported avoidable blindness ranging from 80–95%, with wide geographical disparities [ 9 , 32 – 35 ]. A survey on DR was also conducted in twenty-one districts out of the thirty-one covered in the current survey, in which the prevalence of DR among persons with diabetes was 16.9%, prevalence of STDR was 3.6%, and that of mild retinopathy was 11.8% [ 16 ]. This highlights the pressing need of targeting the avoidable causes in the country, which can be easily treated or prevented.

There remain several districts in India, with little or no population-based data where estimates rely on extrapolation from other regions. The findings of the current study spanning thirty-one districts out of 641 does not provide the status of blindness in the remaining districts. Only state and national level estimates can be deduced. Furthermore, RAAB is not a detailed blindness survey: it provides a reasonably accurate estimate of the prevalence of blindness, and the proportion that is avoidable in a geographic area. RAAB is not designed to give accurate estimates of the prevalence of specific diseases. The estimates for causes of blindness are biased towards more avoidable causes, especially cataract. The small numbers of people found to be blind in the survey means that extrapolations and sub-group analyses has wide confidence limits. The absence of specialised diagnostic equipment meant that cases of posterior segment disease such as glaucoma and age-related macular degeneration were identified by clinical examination only which meant that results for posterior segment causes of blindness must be interpreted with caution.

The present study shows that India has made significant strides towards elimination of avoidable blindness. The prevalence of blindness and visual impairment has reduced significantly since the last national survey. However, the problem still poses a significant challenge in achieving universal eye health and needs a comprehensive and dedicated approach to effectively tackle the situation. In particular, focus is required to improve the eye banking and corneal transplantation services and cataract surgical practices in the country and to integrate refractive services effectively in the existing eye care system.

Supporting information

Acknowledgments.

RAAB India Study group (Prof. Atul Kumar, Ex-Chief, Dr. R.P. Centre, AIIMS, New Delhi, Dr. Promila Gupta, Ex-Principal Consultant, MoHFW, GOI, Prof. R.M. Pandey, HOD, Bio-Statistics Department, AIIMS, New Delhi, Dr. R.S. Dhaliwal, Scientist ’G’ & Head (NCD), ICMR, New Delhi, Dr. V. Rajshekhar, Assistant Commissioner, MoHFW, GOI, Prof. Jagat Ram, PGIMER, Chandigarh, Dr. Arvind Morya, AIIMS, Jodhpur, Dr. B.K. Jain, SSNC, Chitrakoot, Prof. R.R. Sukul, Aligarh Muslim University, Dr. Vishnu Jobanputra, S.S.N.C, Anandpur, Dr. Mehul Shah & Dr. Shriya Shah, Drishti Netralya, Dahod, Dr. Deepshikha Agarwal, MGM Eye Institute Raipur, Dr. Bibhuti Sinha & Dr. Anita Ambastha, IGIMS, Patna, Dr. Asim Sil, VMANNN, Haldia, West Bengal, Dr. BNR Subudhi, MKCG Medical College, Berhampur, Odisha, Dr. Monika Hora, Purnima Netralaya Jamshedpur, Dr. Uday Gajiwala & Dr. Rohan Chariwala, Divya Jyoti Trust, Surat, Gujarat, Col. Madan Deshpandey, H V Desai Hospital Pune, Dr. A.K. Shukla, MGIMS, Wardha, Dr. Pradeep Naik & Dr. Ugam Usgaonkar, Goa Medical College, Panaji, Dr. Dipali Deka, RIO Guwahati, Dr. Ching Sui Yumanam, RIMS Manipur, Dr. Taba Khanna, NPCB & VI, Arunachal Pradesh, Dr. K. Vishwanath, PVRI, Secunderabad, Dr. R.D. Ravindran, Aravind Eye Hospital Madurai, Mr. Bharath Subhramanium, Shankara Eye Foundation, Bengaluru, Dr. Thomas Cherian, Little Flower Hospital Angamaly, Dr. Talvir Sidhu, Research Officer, Community Ophthalmology, Dr. R.P. Centre, AIIMS, Dr. Parul Jain, Research Officer, Community Ophthalmology, Dr. R.P. Centre, AIIMS, Dr. Pranita Sahay, Senior Research Officer, Community Ophthalmology, Dr. R.P. Centre, AIIMS, Mr. Sumit Sharma, Programme Manager, Community Ophthalmology, Dr. R.P. Centre, AIIMS, Mr. Deepak Kumar, Computer Programmer, Community Ophthalmology, Dr. R.P. Centre, AIIMS, Mr. Rajesh Kumar Sharma, Statistician, Community Ophthalmology, Dr. R.P. Centre, AIIMS).

Funding Statement

The survey was funded by the National Programme for Control of Blindness and Visual Impairment, Ministry of Health and Family Welfare, Government of India. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Data Availability