Checking-in With The Problem Solvers

World Hacks follows up on some of our stories from last year – going back to innovators around to world to see how their projects have developed. We hear updates on the app that lets volunteers donate their vision to blind people, the man making roads out of plastic and the compost toilets in Haiti that are turning human waste into soil.Presenters: Harriet Noble and Dougal Shaw Reporters: Amelia Martyn-Hemphill and Nick HollandImage: People Fixing the World illustration / Credit: BBC