Back in the 2000s, Sir Paul McCartney met a yogi who taught him something he hadn't thought about before: eye yoga. The practice involves things like cupping your eyes with warm hands, fast blinking, zooming your vision in and out and tracing a figure eight with your eyes, all in an effort to exercise your eyes and keep your vision sharp. McCartney has carried on with the practice for over two decades now, and the concept of "eye yoga" is growing in popularity. Head over to The Telegraph to learn more about it, and to form your own, professional opinion.