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 PROSPER [PROductivity Study of Presbyopia Elimination in Rural-dwellers] trial, is the first randomized controlled trial to show a link between good sight and work performance.
The research was sponsored by Clearly, a global campaign to bring clear vision to the 2.5 billion people worldwide denied it as quickly as possible. It was carried out in collaboration with VisionSpring, a social enterprise dedicated to providing affordable glasses across the world, and Orbis, a global organization fighting avoidable blindness worldwide.