How do you come to know that your little one has weak eyesight?

Some signs you can look out for include frequent eye rubbing, excessive tearing, sensitivity to light, squinting and tilting his eyes and head when focusing on something. If your child is already in school and have been consistently doing well and all of a sudden there is a drop in grades, his or her eyesight could be the reason. When I was in primary school, I used to ace my spelling tests till I was about 8 and suddenly I would come home with zero test scores. Turns out that I had astigmatism and after I had glasses prescribed, things went back to normal.