If when you look straight in to a mirror, and you can see a bit of white all the way around your iris, you can go for the larger 15mm lenses. This will make your eyes look bigger without filling in too much of your eye.
If you look straight in to the mirror and see that your iris is partially concealed by your eyelid, then you should opt for lenses 14.5mm or smaller. This will give your eyes a more defined, and natural enlarging effect without making your whole eye look dark.
Check out our full selection of Circle Lenses, from 14mm to 15mm and in between.