Prevalence of blindness in India: A systematic review and meta-analysis

Prevalence of blindness and visual impairment in a coastal region of Southern India: A cross-sectional survey in Prakasam district, Andhra Pradesh

PURPOSE

To estimate the magnitude, determinants, and causes of visual impairment (VI) and blindness among people >40 years.

METHODS

In this cross-sectional survey, 2,968 people >40 years from 34 clusters were examined. A cluster random sampling method with a compact segment sampling technique was used to select the study participants. Prevalence of any VI (presenting visual acuity (PVA) <6/12 in better eye), severe VI (PVA <6/60 - 3/60), and blindness (PVA <3/60 in better eye) were expressed as percentage with 95% confidence interval. Logistic regression was performed to determine the risk factors associated with blindness. A P value of less than 0.05 was considered statistically significant.

RESULTS

The mean age of the participants was 54.6 years (Standard deviation ± 11.2 years). The prevalence of mild, moderate, and severe visual impairment was 14.2% (12.95-15.49), 13.7% (12.46-14.97), and 0.7% (0.47-1.12), respectively. The prevalence of blindness was 1.3% (0.94-1.79, n = 39). The overall prevalence of VI (presenting Visual Acuity <6/12) was 12.0% (95% CI: 10.8-13.2%). The major causes of VI were cataract (78.08%), refractive error (12.07%), and optic atrophy (2.22%), and corneal opacity (2.22%) and the major cause of blindness was cataract (77.27%). Blindness was strongly associated with increasing age- OR 17.1 (95% CI: 4.9-59.8) for people >70 years, and OR 7.6 (95% CI: 2.2-26.5) for people aged between 60 and 69 years compared to those aged 41-50 years and people living near coastal regions (Within 50 km of coast) (OR: 3.9, 95% CI: 1.6-7.3).

CONCLUSION

Blindness and vision impairment are of public health concern in this geographic region. Eye care services need to be augmented to address this challenge.

The burden, causes, and determinants of blindness and vision impairment in Asia: An analysis of the Global Burden of Disease Study

Background

Asia accounts for more than half of the world's population and carries a substantial proportion of the global burden of blindness and vision impairment. Characterising this burden, as well as its causes and determinants, could help with devising targeted interventions for reducing the occurrence of blindness and visual impairment.

Methods

Using the Global Burden of Disease Study 2019 database, we retrieved data on the number of disability-adjusted life years (DALYs); crude and age-standardised rates; and the prevalence (with 95% uncertainty intervals (95%UIs)) of blindness and vision loss due to six causes (age-related macular degeneration, cataracts, glaucoma, near-vision impairment, refractive error, and other vision loss) for Asian countries for the period between 1990 and 2019. We defined DALYs as the sum of the years lost due to disability and years of life lost, and calculated age-standardised figures for the number of DALYs and prevalence by adjusting for population size and age structure. We then evaluated the time trend of the disease burden and conducted subgroup analyses by gender, age, geographic locations, and socio-demographic index (SDI).

Results

In 2019, the DALYs and prevalence of blindness and vision loss had risen by 90.1% and 116% compared with 1990, reaching 15.84 million DALYs (95% UI = 15.83, 15.85) and 506.71 million cases (95% UI = 506.68, 506.74). Meanwhile, the age-standardised rate of DALYs decreased from 1990 to 2019. Cataracts, refractive error, and near vision impairment were the three most common causes. South Asia had the heaviest regional disease burden (age-standardised rate of DALYs = 517 per 100 000 population; 95% UI = 512, 521). Moreover, the burden due to cataracts ranked high in most Asian populations. Being a woman; being older; and having a lower national SDI were factors associated with a greater vision loss burden.

Conclusions

The burden due to vision loss remains high in Asian populations. Cataracts, refractive error, and near vision loss were the primary causes of blindness and vision loss. Greater investment in ocular disease prevention and care by countries with lower socioeconomic status is needed, as well as specific strategies targeting cataract management, women and the elderly.

Strategies for cataract and uncorrected refractive error case finding in India: Costs and cost-effectiveness at scale

Background

India has the largest number of individuals suffering from visual impairment and blindness in the world. Recent surveys indicate that demand-based factors prevent more than 80% of people from seeking appropriate eye services, suggesting the need to scale up cost-effective case finding strategies. We assessed total costs and cost-effectiveness of multiple strategies to identify and encourage people to initiate corrective eye services.

Methods

Using administrative and financial data from six Indian eye health providers, we conduct a retrospective micro-costing analysis of five case finding interventions that covered 1·4 million people served at primary eye care facilities (vision centers), 330,000 children screened at school, 310,000 people screened at eye camps and 290,000 people screened via door-to-door campaigns over one year. For four interventions, we estimate total provider costs, provider costs attributable to case finding and treatment initiation for uncorrected refractive error (URE) and cataracts, and the societal cost per DALY averted. We also estimate provider costs of deploying teleophthalmology capability within vision centers. Point estimates were calculated from provided data with confidence intervals determined by varying parameters probabilistically across 10,000 Monte Carlo simulations.

Findings

Case finding and treatment initiation costs are lowest for eye camps (URE: $8·0 per case, 95% CI: 3·4-14·4; cataracts: $13·7 per case, 95% CI: 5·6-27·0) and vision centers (URE: $10·8 per case, 95% CI: 8·0-14·4; cataracts: $11·9 per case, 95% CI: 8·8-15·9). Door-to-door screening is as cost-effective for identifying and encouraging surgery for cataracts albeit with large uncertainty ($11·3 per case, 95% CI: 2·2 to 56·2), and more costly for initiating spectacles for URE ($25·8 per case, 95% CI: 24·1 to 30·7). School screening has the highest case finding and treatment initiation costs for URE ($29·3 per case, 95% CI: 15·5 to 49·6) due to the lower prevalence of eye problems in school aged children. The annualized cost of operating a vision center, excluding procurement of spectacles, is estimated at $11,707 (95% CI: 8,722-15,492). Adding teleophthalmology capability increases annualized costs by $1,271 per facility (95% CI: 181 to 3,340). Compared to baseline care, eye camps have an incremental cost-effectiveness ratio (ICER) of $143 per DALY (95% CI: 93-251). Vision centers have an ICER of $262 per DALY (95% CI: 175-431) and were able to reach substantially more patients than any other strategy.

Interpretation

Policy makers are expected to consider cost-effective case finding strategies when budgeting for eye health in India. Screening camps and vision centers are the most cost-effective strategies for identifying and encouraging individuals to undertake corrective eye services, with vision centers likely to be most cost-effective at greater scale. Investment in eye health continues to be very cost-effective in India.

Funding

The study was funded by the Seva Foundation.

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

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.

Results

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.

Conclusion

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.