The upper cheek/lower eyelid area goes by different names, but commonly the groove or hollow that can be found there is called a tear-trough. Some people have a tear-trough as a matter of genetics while others develop it with age. If you are young and have it, the reason is almost certainly skeletal shape. People who develop it with age may have a skeletal predisposition and then as they age they lose some skeleton (osteoporosis of the skull), have loss of upper facial fat, and some loosening of a piece of tissue called the orbital septum. The orbital septum contains the fat that surrounds your eyeball and stretching of that tissue in combination with loss of bone/soft tissue below it results in bags.
Techniques for correcting the problem include soft tissue filling and implants. For mild cases, Restylane is my preferred choice. When the condition becomes more severe or if the patient desires a more permanent correction, implants are an excellent choice. The implant surgery serves to augment the skeleton. Once in position, it looks and behaves just like bone. The implant is very consistent, it does not change with time, it works on young and old people, and it is very natural. Unlike fat, it does not fail to "take" and can not be lumpy or irregular. It also will not bunch up during smiling as all soft tissue fillers (fat or Restylane) will do when used in excess. For severe cases, soft tissue filling simply can not accomplish what an implant can. When the patient also has stretching of the orbital septum, this can be corrected at the same time smoothing and redistributing that fat so as to smooth the entire area out. The end result is a full and youthful upper cheek/lower eyelid transition area.
Placement of a tear-trough implant is not something that most surgeons are familiar with. If you desire such an implant, I recommend you visit someone who does them on a regular basis.