There are also intrastromal corneal rings to correct myopia (but not astigmatism) -- in the US (Intacs) for -1 to -3 diopter, while in the EU they go up to -6. They're inserted though a small hole to surround the cornea, and they can be removed. So overall less effective than lasers, but also more safe (though much less common, so harder to find a high-traffic expert surgeon).