How do you improve the vision of poor people? Poor as in uneducated less then a dollar a day third world poor. Joshua Silver has invented adjustable glasses to cheaply do this. There are other ideas donating old glasses for example.
The rand experiment showed that one of the few useful free health care provisions are free glasses. Granted that was of fairly rich people who could buy glasses if they really needed them but it still shows a benefit.
See if you can figure out what the picture is used for?