Vision is closely linked to the learning process. Children who have trouble seeing or interpreting what they see will often have trouble with their schoolwork. Many times, children will not complain of vision problems simply because they don't know what "normal" vision looks like.
If your child performs poorly at school or exhibits a reading or learning disability, be sure to have his eyes examined to rule out an underlying visual cause.
Your children may not require glasses but might benefit from eye exercises.