Thinner hyaluronic acid filler products tend to migrate. This is what makes them less likely to lump. While this is a helpful characteristic in certain parts of the face, in my opinion it is not helpful in the under eye area. This tendency for some fillers to drift may contribute to unexpected fullness under the eyes.
If a service is not skillfully placed, any of these fillers can cause these types of issues. I also think this is more likely in individuals who are predisposed to developing festoons-that extra flag of fullness that forms at the top of the cheek just below the lower eyelid hollow. The other situations that seem to predisposed to this type of issue including individuals who have had multiple lower eyelid surgeries and individuals with very thin lower eyelids. In some cases, this issue can be very difficult to resolve without effectively removing every bit of filler. An experienced injector will be reluctant to inject you if you are in one of these categories. Having said that, I have numerous individuals who have had every one of these concerns and yet had spectacular results with under eye Restylane treatment.
Another type of fullness that can be seen after an under eye filler service is a slight reflective highlight in the lower eyelid. These represent very slight areas of overfill caused by the lower eyelid holding just a little too much tissue water in association with the treatment. These are easily adjusted with an enzyme service. Despite the ease with which these can be adjusted, many injecting physicians are not comfortable working with the enzyme. I have seen many patients who were treated elsewhere and lived with this type of easily adjustable issue for well over a year before having this successfully adjusted by me with the enzyme in just one treatment session. Hyaluronic acid filler treatments are adjustable that is one of the reasons they are so popular.