After having seen Laura Mercier Secret Brightening Powder touted all over the place, I decided to try it for myself. I got it in shade 2, which is supposedly best for medium to dark skintones. It still looks like an almost white translucent powder to me, which has a bit of luminescence to it. I applied my normal concealer first, then dusted a tiny bit of Secret Brightening Powder over it. Well, it works. It definitely brightens the look of dark undereye circle. This isn't really a concealer - it's just used to add some luminescence, which makes the skin appear lighter.
I also have applied this over YSL Touche Eclat and it works wonders on a casual day, when I don't want to wear concealer or heavy foundation. Remember to be very light on your application - if you apply too much, you'll wind up with the reverse-raccoon look!
You can buy Laura Mercier Secret Brightening Powder on www.sephora.com or in Sephora stores.