“AT THE end of the day I would be anxious,” says Anil Awasthi, a 44-year-old garment worker in Delhi, “thinking what mistakes of mine would be pointed out.” He was worried about what was going to happen as his sight deteriorated, until—courtesy of VisionSpring, an American social enterprise—he got reading glasses. “I’m confident now that my work will meet my boss’s expectations,” he says. “I go home satisfied.”
For the rich, the worst consequence of long sightedness is having to wear the world’s most ageing accessory. For the poor, things are more serious. “It’s the 42-year-old seamstress or tailor,” says Jordan Kassalow, VisionSpring’s founder. “If they can’t see, they can’t do their jobs, and if they can’t do their jobs they end up breaking rocks by the side of the road.”
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.