Under-eye hollows are characterized by dark circles, deep indentions and a tired appearance around the under-eye area. This skin abnormality is called a tear trough. Because the skin around your eyes is thinner and paler and lacking proper fat restores, your eyes appear more tired and aged. Under-eye fillers are injectable treatments of hyaluronic acid, stimulating the appearance of thicker fat pads under the skin to remove under-eye hollows. Eye fillers typically last 6-9 months