There are a several grades of "thin" lens that look like normal lenses. You can choose the high index lenses that can make your lens much thinner ,but usually they are more expensive, but worth it. Any optical shop will have them. Just ask!
As your prescription is quite strong,it is normal that the lenses should be thick enough.I here that there are high index lenses that is much thinner than the regular one but more expensive. You can go to your nearby optical store to ask.