As usual, the 7 years old children can wear the contact lenses. However, I strongly suggest you not do that, because you know wearing contacts is harmful for the cornea. Once you wear the contact lenses, your cornea will be hurt once. Besides, you know, many children do not know how to put on or off the contacts, and if they do not do it properly, there will be some side effects. For example, the kids' eyes are easily to get infected, because the young children always forget to put off the lenses when they sleep, even though they do, there are more possibilities for the kids to leave bacteria into their eyes. At the same time, you know there is a surgery that can help us to cure the nearsighted, however, if the kids have been wearing contacts for too long time, when the children grow up, the doctor will advise not do the surgery considering the safety of the eyes. Hope my personal experience will help you.