A recent clinical trial found that providing reading glasses may be an inexpensive way to improve productivity, as well as earnings and quality of life, among workers in developing countries. The researchers found that about 700 tea farmer in the Indian state of Assam saw a 22 percent improvement in their productivity after they received glasses to help improve their declining vision caused by age-related impairment, compared to their peers who did not get glasses, Reuters reported. Glasses allowed workers, mostly women aged 40 and older, to increase their tea leaves harvesting from 25 kg per day to 34.8 kg daily during a three-month evaluation period that coincided with the harvest season. The research team wrote in the Lancet Journal that 50-year-old tea farmers, who would likely have more advanced age-related vision impairment, saw a growing productivity rate by about 32 percent after they received glasses compared to their counterparts who did not. "I think this study provides the strongest evidence so far that providing people suffering from aging-related vision impairment boosts not only their productivity, but also their agricultural environments,” said Nathan Congdon, co-author of the study and director of research at EuroPace International.