I think any substance being injected in the periorbital (around the eye) area poses a risk for injection into a blood vessel resulting in blindness or loss of tissue. Fortunately, this risk is very small, and there are some things that can be done to make sure it is minimized. Injecting with a blunt cannula as opposed to a sharp needle is one of those, as you are less likely to puncture a vessel with a cannula as opposed to a needle. Additionally, injecting into the correct plane, or level, in the tissues helps avoid the blood vessels, and it is also safer from the standpoint of the aesthetic result too, as far as lumps and irregularities go. The things that fillers have as advantages over fat from a safety standpoint, are that most fillers injected in the tear troughs are hyaluronic acid based fillers, and those can be dissolved with hyaluronidase if necessary, and they are also temporary, which means they will eventually go away. While this doesn't help much in the setting of an acute complication like intravascular injection with tissue loss or blindness, if there is contour irregularity or lumpiness, we know it won't be potentially permanent as would be the case with fat. I am not afraid to inject fat into the tear troughs at all; I do it all the time. It just has to be done with the proper respect for technique and anatomy, and the proper precautions must be observed. Good luck.
