I even used them in my low-budget horror movie. They cost $300 a pair for full scleral lenses, but they were definitely worth it. Of course, you can get contact lenses a lot cheaper these days. If you're making a horror film or just want to scare the crap out of somebody, it's a time-honored tradition. A lot of places will let you order custom ones too. If you just want to see what's out there, Spooky Eyes has a pretty big selection and cheap prices. For full scleral lenses, check out FX Eyes but be warned. They're a lot more expensive.
I guess you could argue too many horror films use them now, but I disagree especially when you can get so many different kinds. They're a great tool at our disposal that often isn't discussed, which is a shame since they really do add a lot.