My daughter is almost 7 and just wore glass for 1 month. I think 6 to 7 year old is the age/grade they need to go to the govt clinic for body check, it's naturally easy to find that they have short-sightedness. I brought her to Poly-vision (one branch in Hopewell centre, Wan Chai, another one in Poly U) for 2nd check-up (just to ensure..you know, it's hard to accept this FACT at the beginning) and buy the glasses over there. It's more professional. They said as she just have "100 degree", she only need to put the glasses on when doing homework, using computer.