As far as i know, both eyeglasses and contact lenses are made to help people with poor vision. They can help them get better vision when they wear them. But both eyeglasses and contact lenses can't cure vision problems. They only correct vision when you wear them. If you take them off, you are still with poor vision. Anyway, they can improve your vision if you need as long as you wear them.
Glasses and contacts can help correct vision problems. They are assists for your eyes. But if you mean you want to get perfect vision or improve your vision after wearing them for a long time, you may definitely get a wrong idea.