If you need some reading glasses in the United States, you don't have to break the bank to pick some up. That's important for older folks who need a little extra magnification. But in some parts of the world, people who need readers don't have that privilege. Today on the show, we'll find out why that is and learn the economic solution to the reading glasses shortage.Related episodes:Two indicators: supply chain solutions (Apple / Spotify) For sponsor-free episodes of The Indicator from Planet Money, subscribe to Planet Money+ via Apple Podcasts or at plus.npr.org.Music by Drop Electric. Find us: TikTok, Instagram, Facebook, Newsletter.