What is the burden and prevalence of cataracts (clouding of the lens in the eye) in India?

Burden and Prevalence of Cataract in India

Cataract is the predominant cause of blindness in India, affecting approximately 43% of people aged 50 years and above, with an estimated 11.9 million blind people urgently needing cataract surgery. 1

Prevalence of Cataract

• The prevalence of cataract among Indians aged 50+ years is 43.32% (95% CI: 41.14-45.50) 1
• Prevalence increases significantly with age:
  • Individuals aged 60-69 years have 2.74 times higher risk of cataract blindness
  • Those aged 70+ years have 4.86 times higher risk compared to those 50-59 years 1

Blindness Burden

• The prevalence of bilateral blindness (vision <6/60 in better eye) is approximately 11.68% (95% CI: 10.54-12.81) among those aged 50+ years 1
• When using best-corrected visual acuity, blindness prevalence decreases to 4.6% 2
• In Gujarat (a high cataract surgical rate area), presenting bilateral blindness was 6.9% (95% CI: 5.7-8.1) and 3.1% with best correction 3

Causes of Visual Impairment

• Cataract is the principal cause of blindness in at least one eye in 70.6% of blind people 2
• In Gujarat study (2010), cataract remained the main cause of bilateral blindness (82.6%), followed by retinal disorders (8.9%) 3
• For eyes with vision <20/63 to 20/200, cataract (50.3%) and refractive error (35.4%) were the main causes 3

Risk Factors and Disparities

• Blindness is significantly associated with:
  • Older age
  • Female sex
  • Illiteracy 2, 3
• Occupational status impacts blindness rates:
  • Productively employed individuals have lowest blindness rates
  • Blindness rates are five times higher among those not working
  • Rates are two times higher among those engaged solely in household activities 1

Cataract Surgery Coverage

• The prevalence of cataract surgery among those aged 50+ years ranges from 11.8% 2 to 13.9% 4
• Estimated 56.5% of cataract blind have already been operated on 2
• Surgical coverage is inversely associated with:
  • Illiteracy
  • Female sex in rural areas 2

Visual Outcomes After Surgery

• In a 2016 study from rural South India, post-cataract surgery outcomes showed:
  • 53.1% had good outcomes (VA ≥6/18)
  • 38.1% had fair outcomes (VA <6/18 but ≥6/60)
  • 8.8% had poor outcomes (VA <6/60) 4
• With pinhole correction, good outcomes improved to 75.2%, indicating significant uncorrected refractive error 4
• 76.3% of eyes with fair and poor presenting outcomes had avoidable causes 4
• Pseudophakic eyes had better outcomes than aphakic eyes 2

Healthcare Challenges

• Despite a high cataract surgical rate (>10,000 per million population in Gujarat), cataract remains the predominant cause of blindness 3
• Annual incidence of cataract blindness is approximately 3.8 million cases 5
• To address the backlog and rising incidence, India needs to perform 5-6 million cataract surgeries annually, compared to the 1.7 million per year reported in 1999 5

Implications

• Cataract blindness presents not only a human morbidity problem but also causes significant economic loss and social burden 5
• Treatable blindness, particularly from cataract and refractive error, remains a significant problem among older adults in India 2
• The high prevalence of avoidable causes of visual impairment indicates substantial scope for preventive strategies 4