I found this chart at my optomotrist. Wasn't able to find a clearer version online, but if you click on the photo you'll get the large-size view.
It's basically a guideline as to how and what a child should be able to learn as a baby, toddler, pre-schooler, up to Kindergarten.
But the most important message is children's eyesight. Early detection of vision problems is crucial, and the value/need of glasses should a child need them.