If you want red ones that don't leave a ring around the pupil, they make contacts for soccer players that make your irises red, but because the colour goes over the pupil they'll also make everything look yellowish when you wear them. (they're supposed to make the ball easier to see or something.) I don't know if they'd work for darker eyes, though. My friend was wearing them and they looked really cool, so if you don't mind seeing everything in yellow for the day... I know I'm going to look for them.