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    Restoring sight

    Restoring sight: Give people their sight back.

    For at least 1 billion people, poor sight could have been prevented or still hasn't been treated. Often the fix is a short operation or a pair of glasses.

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    Ryan K. Hertel · heyitskenton

    The problem

    What we're up against.

    • Cataract leads.

      Cataract causes the most untreated loss of distance vision, 94 million people, with uncorrected refractive error close behind at 88.4 million.

    • Growing with age.

      In 2020, cataract left 17 million people blind and 83.5 million more with moderate or severe vision loss. Population growth and aging have outpaced the gains.

    • Too many go without a good result.

      Worldwide, only 48.2% of the people who need cataract surgery get it with a good result; in the WHO African region, just 23.6%.

    • Trachoma still blinds.

      92 million people live where trachoma, a blinding eye infection, is still endemic.

    What works

    Proven, and ready to grow.

    • Surgery lifts whole households.

      In Kenya, the Philippines and Bangladesh, households of people who had cataract surgery caught up with their neighbors' spending per person.

    • Reading glasses, more work done.

      In a randomized trial in India, free reading glasses raised tea pickers' harvest by 21.7%, for $10.20 a person including delivery.

    • And more income.

      In a randomized trial in Bangladesh, workers given reading glasses reported 33.4% more income than those without.

    • Glasses help children learn.

      Free glasses raised math scores by 0.11 standard deviations among short-sighted children in rural China.

    • Antibiotics against trachoma.

      A single dose of azithromycin given to whole communities reduces active trachoma and infection.

    What a family could fund

    Where the money goes furthest.

    • Surgery at a known price.

      At India's Aravind Eye Care System, an operation cost $120 in total, or $195 for each year of healthy life gained.

    • A model that pays its way.

      Aravind says 50% of its patients are treated free or at steeply subsidized rates, and it still pays its own way. Its results have steadily improved.

    • Others, at similar prices.

      Cure Blindness Project puts its all-in cost at $70 a surgery, by its own figures.

    • Glasses for workers.

      GiveWell's best guess is that glasses for workers are 11 to 15 times as cost-effective as giving cash, and it sees significant room for more funding.

    • The medicine is already free.

      The antibiotic for trachoma is given free by its maker, so money pays for getting it to people. In 2025, coverage was 47%.

    Honest limits

    What money can't promise.

    • Results vary.

      In Burundi, almost 4 in every 5 people who had cataract surgery did not end up with good vision.

    • The price of a result is uncertain.

      GiveWell estimates cataract programs may cost $112 to $1,250 for each case of severe vision loss reversed, and has low confidence in those numbers.

    • Too few surgeons.

      Low-income countries have 3.7 ophthalmologists for every 1 million people, against 76.2 in high-income countries.

    • Glasses only work if they're worn.

      In the China trial, only 41% of children given free glasses were seen wearing them. In Baltimore, reading gains from school glasses faded by the second year.

    • Antibiotics carry a cost.

      Treating whole communities with antibiotics raises the risk of antibiotic resistance.

    Hard questions

    Asked and answered.

    1. You might ask

      Is a decade-old cost figure still right?

      Ryan

      Probably not exactly. From 2012 to 2023, Aravind's prices for paying patients rose slightly faster than India's health inflation. Treat it as a benchmark for high-volume care in India, not a price for the world.

    2. You might ask

      Why not train local surgeons instead?

      Ryan

      It isn't either-or. Trained eye care workers perform trichiasis surgery about as well as ophthalmologists, and a family's initiative can pay for training alongside the surgery.

    3. You might ask

      Isn't this the government's job?

      Ryan

      Governments and insurers are paying more: at Aravind, their share of surgeries rose from 4.4% to 28.7%. Still, only 48.2% of the people who need surgery get a good result, so the gap is real.

    In the slider

    See what your fortune could do here.

    Restoring sight

    The slider prices this cause with these numbers:

    • About $120 a surgery, the full cost at India's Aravind Eye Care System.
    • The whole need is everyone whose sight is impaired by cataract, 94 million people.
    • Costs measured at one system in India over a decade ago. Elsewhere surgery can cost more.
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    More of the Blueprint

    Keep reading.

    23 more chapters on the way

    Back to Keep 100

    Sources

    Every number in this chapter, and where it came from.

    1. Source 1: Blindness and vision impairment: fact sheet (opens in a new tab)

      World Health Organization, 10 February 2026. Checked 15 October 2026.

      People with distance vision impairment or blindness caused by cataract.

    2. Source 2: Global estimates on the number of people blind or visually impaired by cataract: a meta-analysis from 2000 to 2020 (Vision Loss Expert Group) (opens in a new tab)

      Eye, 9 March 2024. Checked 16 October 2026.

      A meta-analysis; figures for 2020.

    3. Source 3: Effective Cataract Surgical Coverage trends highlight gaps in cataract services towards 2030 targets (opens in a new tab)

      International Agency for the Prevention of Blindness, 9 March 2026. Checked 16 October 2026.

      Effective coverage counts people who had surgery with a good result, out of everyone who needs it. A summary of a study in The Lancet Global Health.

    4. Source 4: Trachoma: fact sheet (opens in a new tab)

      World Health Organization, 7 September 2026. Checked 16 October 2026.

    5. Source 5: Does Cataract Surgery Alleviate Poverty? Evidence from a Multi-Centre Intervention Study Conducted in Kenya, the Philippines and Bangladesh (Kuper and others) (opens in a new tab)

      PLOS One, 9 November 2010. Checked 16 October 2026.

      Compares patients with matched neighbors; not a randomized trial. PCE is household spending per person.

    6. Source 6: Effect of providing near glasses on productivity among rural Indian tea workers with presbyopia (PROSPER): a randomised trial (Reddy and others) (opens in a new tab)

      The Lancet Global Health, 23 July 2018. Checked 16 October 2026.

      A randomized trial with 751 tea workers in Assam.

    7. Source 7: The effect on income of providing near vision correction to workers in Bangladesh: The THRIVE randomized controlled trial (Sehrin and others) (opens in a new tab)

      PLOS One, 3 April 2024. Checked 16 October 2026.

      Income was reported by the workers themselves.

    8. Source 8: Effect of providing free glasses on children's educational outcomes in China: cluster randomized controlled trial (Ma and others) (opens in a new tab)

      The BMJ, 23 September 2014. Checked 16 October 2026.

      A randomized trial in 252 rural schools.

    9. Source 9: Antibiotics for trachoma (Evans and others) (opens in a new tab)

      Cochrane, 26 September 2019. Checked 16 October 2026.

    10. Source 10: A Sustainable Model For Delivering High-Quality, Efficient Cataract Surgery In Southern India (Le and others) (opens in a new tab)

      Health Affairs, October 2016. Checked 15 October 2026.

      The full cost per operation at the Aravind Eye Care System, measured in 2013.

    11. Source 11: Our Story (opens in a new tab)

      Aravind Eye Care System. Checked 16 October 2026.

      Aravind's own account.

    12. Source 12: Changing patterns in cataract surgery indications, outcomes, and costs, 2012-2023: a retrospective study at Aravind Eye Hospitals, India (Gupta and others) (opens in a new tab)

      The Lancet Regional Health: Southeast Asia, 17 January 2025. Checked 16 October 2026.

      A study of 3.6 million surgeries, by Aravind's own researchers.

    13. Source 13: Cure Blindness Project (opens in a new tab)

      Cure Blindness Project. Checked 16 October 2026.

      The organization's own figure.

    14. Source 14: London School of Hygiene & Tropical Medicine: RCT of Eyeglass Provision (May 2024) (opens in a new tab)

      GiveWell, August 2024. Checked 16 October 2026.

      GiveWell is still testing this, with a randomized trial in India and Kenya.

    15. Source 15: Cataract Surgery (opens in a new tab)

      GiveWell, March 2021. Checked 16 October 2026.

      First published in August 2016, last updated in March 2021.

    16. Source 16: Estimated number of ophthalmologists worldwide (International Council of Ophthalmology update): will we meet the needs? (Resnikoff and others) (opens in a new tab)

      British Journal of Ophthalmology, April 2020. Checked 16 October 2026.

      A survey of 194 countries, with figures from 2015, the newest global count.

    17. Source 17: Effect of a Randomized Interventional School-Based Vision Program on Academic Performance of Students in Grades 3 to 7 (Neitzel and others) (opens in a new tab)

      JAMA Ophthalmology, October 2021. Checked 16 October 2026.

      A randomized trial in Baltimore schools.

    18. Source 18: Interventions for trachoma trichiasis (Burton and others) (opens in a new tab)

      Cochrane, 13 November 2015. Checked 16 October 2026.