My 7 year old has severe myopia, which he has been wearing glasses for for the past year. At his eye exam last week, it was discovered he has double vision, which makes him occasionally dizzy and nauseous. The double vision is not constant, but comes and goes. He also has a hard lump on his head, sort of on his forehead. Should I be concerned about this, or will the vision problems be corrected with his new prescription?