A list of symptoms has been given to help parents identify certain sight problems in their children.
In an Examiner article, Candace Brault explained that older children may not realise they cannot see properly and so might not tell their parents about it.
But she noted that if a child is squinting when looking at things that are near or at a distance, he or she may have myopia (near sight) or hyperopia (far sight).
Myopia sufferers may also report difficulty in seeing the board at school, while hyperopic children could be unable to concentrate on books or close-up tasks.
Amblyopia, or lazy eye, does not usually have clear symptoms but children may have one eye turning in or out.
Crossed eyes, or strabismus, may display themselves in a child looking at a person with one eye while the other turns in another direction.
Recently, the Canadian Press spoke to Ohio State University College of Optometry assistant professor Jeffrey J Walline about glasses for children.
He said that children often associate people with glasses with higher intelligence.
by Alexa Kaczka