RCT study quantifies eyeglasses impact on worker's productivity.

Landmark Study

Proves and Quantifies Impact on Worker's Productivity.

Called PROSPER, the study affirms that eyeglasses have the potential to dramatically boost worker productivity worldwide. In India, providing tea pickers with corrective lenses improved worker productivity by 21.7 percent, with productivity increasing to almost 32 percent when vision correction was provided to workers over 50. This represents the largest ever recorded productivity increase from any health intervention.

The randomized control trial offers the most compelling and definitive evidence to date linking eyeglasses and productivity. The research was a collaborative effort undertaken by VisionSpring, Clearly, Orbis, and Queens University Belfast.

Read more about the results

Largest ever recorded productivity increase from any health intervention

 Increase in Productivity by

Increase in Productivity by


on an average when tea pickers were provided with corrective lenses.


In Workers Aged over 50

In Workers Aged over 50


productivity increase was measured when vision correction was provided.

Willingness to Buy

Willingness to Buy


workers expressed readiness to purchase glasses if theirs were lost or broken.

Glasses and Socio-Economic Development

A trial of Indian tea pickers, has shown that the provision of glasses improved their productivity by 21.7 per cent – and for those aged over 50 the increase was 31.6 per cent.

This represents the largest ever recorded productivity increase from any health intervention.

The findings – in a study called PROSPER [PROductivity Study of Presbyopia Elimination in Rural-dwellers], is the first trial to show a link between clear vision and work performance. A collaborative effort between Clearly, Orbis International and VisionSpring, the study offers the most compelling evidence to-date of the incredible impact vision correction has on productivity among low-income workers in an agricultural setting.

The trial was carried out over a period of three months in tea-plantations in Assam, India, with reading glasses given to 750 mostly-female Indian tea pickers, aged between 40 – 50 +years. The daily weight of tea picked increased by 5.25 kilogrammes a day (21.7%) overall when compared to controls over a three-month period, with the largest increase seen in those over 50, with an increase of 31.6 %. Nearly 90% of workers were still wearing their glasses by the end of the study, and virtually all were willing to pay to replace them if needed—a sure sign of how much the glasses were valued.


Read the full academic article