What is the best filler that lasts the longest for under eyes?

As noted by the
other doctors here, the most appropriate filler for the eye area may not be the
one that lasts the longest, but does look the best. Under the eyes we usually recommend
Restylane, Belotero, or Juvederm, as these are the softest of the fillers that
we have. Make sure that the injector is
skilled in these kinds of injections and preferably is or works with a board
certified dermatologist or plastic surgeon.
If you are having a CO2 laser procedure there is no hard and fast rule
here. Many would consider doing them at
the same time, but others would recommend that they work best if done 2 weeks
before and some even 2 weeks after.
Again, the skill level of the provider is most important.

In general, all fillers last longer under eyes since it is a less dynamic movement-oriented area than the lips or smile lines. Restylane® and Belotero® are the currently-favored fillers for this area, since their lower viscosity (thickness) causes less puffiness/swelling of delicate under eye skin.