The stars' eyes lack a lens like the compound eyes of insects, cannot process quick movements, and cannot sense colors, so they are unlikely to be used for finding food or avoiding predators. To find out if they could sense large objects like reef corals, the scientists placed sea stars at a distance of 1, 2 and 4 meters (3.24, 6.5 and 13 feet) from the corals. Those closer than 4 meters quickly returned to the reef, whereas those at 4 meters moved in random directions. They also preformed the experiment with blinded sea stars, the eyes of which had been poked out. (Ouch. Sorry, sea stars.) All of these animals moved at random, suggesting they couldn't see where they were going.