Pardon me but what is an astigmatism?
The cornea is meant to have a perfect curvature or sphericity. An astigmatism is when the cornea has an anomaly in the curve.
If you have an astigmatism and wear hard contact lenses, the lens will pull the cornea into shape. This remains for sometime after you stop wearing them. I used to wear these lenses and when I would lose them my vision was almost perfect for up to three weeks. It is worth a try as hard lenses don't cost the earth.