It's playtime at Hu Jia Lou Centre Primary School in the centre of Beijing. Just outside the main entrance is a bus. Nothing so strange in that you might think - that is, until you step inside."
Inside, the bus is like a small eye clinic with equipment to scan eyes and prescribe classes. It's driven around Beijing visiting schools and can give up to 400 eye tests per day. 10 year old Cao Shi Yi is one of the many kids having her eyes checked today. She's worn glasses for six years and has a hard time without them.
"It's really difficult and when I don't wear glasses I almost can't see anything – I can't see what teachers write. So, it's bad."
