Ontario's eye doctors are encouraging parents to get their children's eyes checked out, reminding people that an estimated one in six school-aged children has a vision problem.

Tim Dunford is glad he got his son's eyes checked out “With Liam especially and now my younger son Caleb, we had no idea their eyes were as poor as they were. And without having the eye exams we would have never known."

Six-year-old Liam gets regular eye exams, something that optometrists like Dr. Tim Wilbee say are important for all children.

"Generally speaking we start seeing them around the age of two-and-a-half or three…and often times we want them to have yearly examinations until we're comfortable through stages of their development that there's really no vision issues."

Sometimes the signs that a child needs glasses can be obvious, but they can also be subtle.

"Sometimes they'll be avoiding reading would be a big one. Sometimes if they're stuck at the back of the classroom maybe the teacher might pick up the fact that they’re squinting to see the board a little bit better,” Wilbee says. “Headaches, eye strain - those are the types of things that I would say would be the big characteristics that you want to be watching for from a parent's point of view."

As for when it might be time to switch from glasses to contact lenses, there are no hard and fast rules about ages. But contact lenses do require care, so the child should be old enough to care for them.

Liam just started Grade Two this week, and he's seeing just fine. And his dad says getting glasses has made a dramatic difference.

“Riding a bike, daily activities, things that you took for granted. You would really say ‘He doesn't want to learn to ride a bike,’ or whatnot. It was actually due to his eyesight.”