It is supposed to work by flattening the curve of the retina so that the light rays can reach the retina properly. In short sight and astigmatism, the light is unable to focus on the retina fully, which causes images to appear blurred. So in the morning your retina form should have been corrected enough to show a definite improvement in your vision (though it can't correct long sight).
It should start working quite quickly; the effects aren't permanent though, so if you stopped using the lenses the retina would eventually go back to its previous shape.
Dream lenses need to be fitted by a trained practitioner and aren't available at an ordinary optician's yet, but it is worth consulting your regular practitioner before you think about looking for a Dream lens specialist. In any case it may be hard to find one at present; on their website the only registered doctors seem to be in the US at the moment, so it depends where you live.