It's just like perming hair. You get different sized rollers dependant on the length of your lashes so it works well on anyone.
I had it done once and for the first day I could see my lashes in front of my eyes! It was really freaky! I felt like a camel. hahahaha! But as in normal perms, the curl does drop and takes on a more natural curve.
It's nice, but I wasn't too fussed with it. I'm not that bothered about curling my lashes with curlers at the best of times anyway.