It’s called a Snellen chart, and it’s actually over 160 years old. Credit: Nature CommunicationsAshraf and colleagues swapped out the traditional Snellen chart for their own experimental arrangement. Next, they asked study volunteers to stare at the display screen with various patterns, both in shades of gray and in color. A gray areaThe team discovered that our eyes (sometimes) have a higher resolution limit than the Snellen chart would have us believe. There may be a limit to visible pixel resolution, but you’ll at least be able to spot the next time someone’s trying to upsell you on a TV.