How long does a lower eyelid surgery last? I am interested in lifting the lower eye and having fat injected in the eye trough.

There are two ways to answer this question - the first is that improvements following a #blepharoplasty also called an #Eyelift procedure are life long. You turn back the hands of time permanently, but the clock still keeps on ticking. The second answer is that if done right the first time in my experience it does not have to be redone for decades before loose skin is bothersome again. In my 30 yrs of practice I have only had to do a #repeatEyelidLift less than a dozen times.

Most lower eyelid procedures are essentially permanent, as the fat herniation causing puffiness rarely returns. Some patients will continue to have progressive skin laxity and will need a skin pinch 10-15 years later. Occasionally, new fat pockets can pop up laterally (towards the side of the lid) and will require removal. Sometimes this can be done directly and sometimes it requires a revision procedure. Fat injection to the tear trough may require additional volume down the line as midfacial ptosis continues to progress. There is no specific timetable for this need, as everyone's face ages differently.All in all, both are great choices for longevity and patient satisfaction.

Lower eyelid surgery rarely has to be redone. It should last over 10 years and smaller refinement procedures can be performed to maintain eyelid rejuvenation such as fillers in the tear trough (as you have mentioned) and resurfacing procedures. There are are different options for eyelid rejuvenation (see pictures/examples on my (Instagram and Facebook drmadnani) so get an evaluation by a plastic surgeon with lots of experience in this area as one size does not fit all. 

The results of eyelid surgery will last ten to fifteen years. The restoration of volume with fat grafting will help to smooth the areas under the eyes. Fat should not be injected, but rather grafted with a cannula. As the years go by you may require a little "tune up" fat grafting or "tune up" skin excision.  Do look for a plastic surgeon who is very experienced with fat grafting of the eyelids. Over-correting this area could result in a puffy and unnatural look. 

Surgery is always the longest-lasting method to correct eye
issues. Typically, blepharoplasty results should last up to 20 years. It's good
to remember that aging never stops, which is why the results are not permanent.
But they are certainly long-lasting, and this type of surgery is really
effective at achieving great results.