Been wearing them for YEARS....I first notice I couldn't focus on the target when I was about 25, I also have astigmatism, and when I went and got my eyes checked I was like 20/50 and 20/60, got glasses and "BAM!!!" I can see to shoot again. Frustrating, but I suppose its part of life we have to deal with.
The LOW LIGHT problem is because the glasses, just like a scope, cut down on a small percentage of the light that shines through them, preventing you from seeing quite as well in low-light. Not really a whole lot you can do unfortunately.