Gender differences in blindness, cataract blindness and cataract surgical coverage in India: a systematic review and meta-analysis

Author: Prasad M, Malhotra S, Kalaivani M, Vashist P, Gupta SK.

Geographical coverage: India

Sector: Cataracts, blindness

Sub-sector: Gender

Equity focus: Gender

Study population: Adults aged ≥ 50 years with cataract

Review type: Effectiveness review

Quantitative synthesis method: Meta-analysis

Qualitative synthesis method: Not applicable

Background

Globally, more than 36 million people are blind and, without effective prevention, the figure could exceed 114 million by 2050. The burden is greatest in low- and middle-income countries and 81 % of those affected are aged 50 years or above. Evidence indicates that blindness is not evenly distributed between the sexes: women experience greater visual-health disparities, particularly in India where cataract remains the leading cause of blindness. Unequal access to cataract surgery is thought to drive the difference. Quantifying the magnitude of sex-based inequalities is therefore essential for equitable eye-care planning and for identifying barriers to treatment.

Objective

To investigate sex differences in the prevalence of blindness, cataract blindness and cataract surgical coverage (CSC) among Indians aged 50 years and over.

Main findings

Twenty-two population-based studies were included; twelve contributed to the meta-analysis. Most were conducted in rural southern India. Participant mean ages ranged from 61 to 70 years.

• Overall blindness
  • Prevalence: women 5.68 % vs men 4.17 %
  • Women had 35 % higher odds of blindness (OR 1.35, 95 % CI 1.08 – 1.62).
• Cataract blindness
  • Prevalence: women 6.13 % vs men 3.92 %
  • Women had 69 % higher odds (OR 1.69, 95 % CI 1.44 – 1.95).
• Cataract surgical coverage
  • CSC: women 52.3 % vs men 59.3 %
  • Although the difference approached statistical significance (OR 0.73, 95 % CI 0.45 – 1.01), it indicates lower surgical uptake among women.

Population-attributable fractions suggested that 35 % of blindness and 33 % of cataract blindness in women could be attributed to their sex, underscoring systemic and societal contributors to inequality.

Methodology

Searches of MEDLINE, Web of Science, EMBASE, Google Scholar and TRIP (1990 – 2018) identified Indian population-based studies reporting sex-specific prevalence of blindness, cataract blindness or CSC in adults aged ≥ 50 years. Two reviewers independently screened records, extracted data and assessed quality with the CASP checklist; discrepancies were resolved by consensus or a third reviewer. Random-effects meta-analysis was employed; heterogeneity (I²) and publication bias (funnel plot, Egger’s test) were evaluated.

Applicability / external validity

By pooling data from diverse rural and urban regions, the findings are broadly applicable across India for older adults. External validity beyond India was not discussed.

Geographic focus

The included studies were all conducted in India.

Summary of quality assessment

Confidence in the review’s conclusions is medium. Searches were comprehensive, inclusion criteria explicit and dual-review processes employed. Study characteristics were well documented and meta-analysis appropriately undertaken with heterogeneity addressed. However, the review did not clarify language restrictions, provide a list of excluded studies or confirm reference-list or expert searches.