I have been injecting the tear troughs with fillers for well over three decades, since the early years with the original Zyderm I collagen filler. In recent years, hyaluronic acid based fillers have captured the filler market and have become the main filler for use in the infraorbital region. Although plain Restylane was at one time routinely used for this purpose, particularly when diluted, more recently Restylane Silk and Belotero Balance (which I use in my Upper East Side Manhattan practice) have become the go-to products, since they are unlikely to give rise to lumpiness, and particularly the latter product possesses little to no tendency engender the unwanted, bluish Tyndall Effect when injected superficially into the delicate skin under the eyes. (In my Israel satellite facility, where a far greater number of regulatory agency approved fillers are available, I typically opt for Teosyal Redensity II). In my experience, since the region under the eyes is subject to so little mechanical force (even at extreme squinting), the duration of the desired effect of the injected materials tends to be considerably longer, and I have had quite a number of patients who have gone three or more years before needing any additional treatment. I myself went for longer than five years before I needed to retreat my under eyes. Make sure that you consult with a board certified aesthetic physician with experience and expertise in treating the infraorbital region, which is certainly an area not to be left to medspas and physicians accustomed only to treating ordinary smile lines with simple Juvederm or Restylane. Make sure to ask to see his/her before and after photos before agreeing to proceed. Best of luck.