
Effect of providing near glasses on productivity of Indian tea workers over 40 - js2
https://www.thelancet.com/journals/langlo/article/PIIS2214-109X(18)30329-2/fulltext
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js2
I submitted the Economist story on this study but HN flagged it.

[https://www.economist.com/science-and-
technology/2018/08/04/...](https://www.economist.com/science-and-
technology/2018/08/04/wear-glasses-earn-more)

> The first randomised control trial to measure the impact on productivity of
> reading glasses was carried out recently in a tea estate in Assam, in north-
> eastern India, paid for by Clearly, a charity. Nathan Congdon, a professor
> of ophthalmology at Queen’s University, Belfast, and his colleagues gave
> spectacles to half of a group of 751 tea-pickers aged over 40. The other
> half got none. Over 11 weeks, the productivity of those whose sight had been
> corrected rose by 39%. It rose for the others, too, showing the importance
> in such trials of having a control group. But that rise was only 18%. The
> rise in productivity for those with glasses was the largest caused by a
> medical intervention that has ever been shown in such a trial (others have
> been of mosquito nets and micronutrients). Since tea-picking is piecework,
> productivity translates directly into money.

> Before Dr Congdon’s trial, none of the 751 had worn glasses. Given the
> potential gain in income, and the cheapness and simplicity of spectacles,
> that seems odd. It is not, however, unusual. Some 1.1bn people suffer from
> uncorrected long sight. In this, as in many areas of health, both
> governments and the market fail the poor.

> Poverty is one explanation. Liberia, says Dr Congdon, has but two eye
> doctors, both in the capital. Even in China, which is far better-served,
> half of those with poor sight do not have the glasses they need. There are
> social issues: some people worry that spectacles make them look ugly. There
> are regulatory hurdles, too. In some countries, only licensed operators may
> sell glasses, so hardly anybody does. And because long sight creeps up on
> people, victims get used to it: “They probably thought, ‘you get to 50, you
> can’t pick like you used to’,” says Dr Congdon of the tea-pickers. “But by
> the end of the trial, their productivity was as good as the youngsters’.”

