Surgical treatment of hollow eyes
I am personally against the injecting of any filler (fat or off the shelf filler) around the eye. I do not like the risk of blindness with these procedures. Despite that many doctors do inject fillers in these areas with good results and happy patients.
There are inherent differences between restylane and fat. The restylane for one is guaranteed to go away so there would be a need for repeat injections for ever. Fat if it survives the transfer process on the other hand will be there forever. You need to be aware though that injecting fat in these areas has a high risk of forming lumps. This is probably due to the constant muscle movement of blinking. I prefer to place a fat graft as a sheet of fat right on the bone rim via a blepharoplasty incision. This gives me a more even result with risk of blindness or lumps.
Under Eye Hollows - Fat VS Restylane
In the correction of the Tear Trough / Under Eye Hollows / Nasojugal line BOTH fat and Restylane do a great job. But each has is plusses and shortcomings.
Restylane is easier to obtain and inject and is associated with much less swelling. It fills everywhere it is placed but is a temporary filler. If you do not like the appearance, it can be readily dissolved with a simple injection.
Fat, on the other hand, needs to be removed from elsewhere in YOUR body. It needs to be separated from any associated blood and then injected carefully. The fat transfer is associated with significant swelling and some of the fat cells do not survive which may results in areas of lumpiness and depression. The fat that survived lasts a lot longer than Restylane so BOTH good and bad results are nearly permanent (because unlike Restylane fat cannot be dissolved and no one would be stupid enough to attempt liposuction in this location).
Restylane of fat grafting: the chicken or the egg?
This is not an either/or question. In my experience, I highly adivse patients to consider restylane as a "lunchtime lift" to "try out" the appearance of a corrected tear trough. If they like this and desire longer term correction and are willing to tolerate the surgical recovery, I suggest fat grafting as a longer term solution,