When we were young we were told to look at the trees, the green leaves as it helps "improve" myopia. Is it true?

Hi there, actually it is not the colour of the thing you're looking at that makes the difference. Green objects do not have any eye sight improving properties and neither does any other colour for that matter. It is how far away they are. When you are looking at faraway objects, your eye muscles get more relaxed compared to focusing on things that are close. This myth probably came about because trees and grass are traditionally thought of to be faraway in paintings and landscapes haha.