I have an astigmatism. I found this out today.
I've been struggling with distance vision attached with contact lenses for a couple years. Near vision is no problem, but distance has been legible, but fuzzy.
Today, I got a bit of an explanation, and new contacts.
I was told they were toric lenses. I asked if that was based off of torus, and she just repeated that they were toric. It just goes to show that simply because you're a doctor does not mean you've learned everything there is to know about topology (and going by my Chrome spellchecker, neither do the people at Google).
Clarification for those who didn't keep up with three dimensional figures in math, go here.
The lenses are not cut from a sphere, so they have a definite up and down. When I put them in, while there is no specifically different feel, my distance vision si still fuzzy. But as I blink and the lenses settle into position, distance clarified.
So my eyes are almost the same prescription, but they require a different bit of toroidal (another word Chrome doesn't recognize) section to fix my sight.