Clearly : how a 700-year old invention can change the world forever

Poor vision is the largest unaddressed disability in the world today. An estimated 2.5 billion people, mostly living in the poorest parts of the planet and a majority of whom are women, cannot see clearly and have no access to treatment. Yet for 80 per cent of the 2.5 billion, all they need is a simple pair of prescription spectacles. Tackling this problem would unlock billions of dollars in productivity gains. It would give young people a better...