Thank you for the great questions. Your description of the issues is spot on. Unfortunately, as we age, the cheek fat descends and the lower eyelid fat starts to push forward. Since the lower eyelid skin is so this, this causes a contour abnormality and shadowing. And the result is dark circles and a hollow appearance. This can be treated very well using soft tissue fillers; I prefer Restylane for this area. The benefit of this option is that it is quick and does not require anesthesia or down-time. The downside is that it is temporary. For most patients, the filler material lasts about 9 months. A lower eyelid lift surgery is also a great option, and obviously permanent. In my practice, I use the lower eyelid fat to help fill in the hollow area of the tear trough. This requires about a week of downtime, depending on the patient. Best of luck moving forward!