How often/is it possible for under eye filler (restylane) to move from its original spot?

I have been injecting fillers under the eyes for over three decades, since the early days with the use of the original Zyderm collagen for this purpose. Nowadays, while we have much more sophisticated and elegant fillers for these purposes, such as Restylane Silk, Belotero Balance, Teosyal Redensity II, Aliaxin FL, etc., I have not as yet encountered a single episode in all these years of filler migration, which, if it occurs at all, must be extremely rare.  So, relax and enjoy your results. Best of luck. 

I agree with my colleagues that eyelid filler migration is uncommon.  The filler and a little massage simply are not able to dissect out a new plane in the soft tissue.  Rest assured, the results can be uniform and long lasting