Dark eye circles are mainly attributed to:
1) Under eye hollowing/ loss of volume with the resultant shadowing causing the area around the eyes to appear darker than it is
2) Blood vessels showing through the skin
3) Pigmentation
Treatment include:
1) Under eye Hyaluronic Acid (HA) fillers. This replaces the volume loss under the eyes and the HA hydrates and draws moisture up to 1000x. This improves the shadowing under the eyes and coupled with the hydration, will improve the dark eye circles
2) Pigment-specific lasers that target pigment around the eyes.
Prominent eye bags are caused by the loss of volume under the eyes and herniation of the orbital fat forwards. Sometimes, the loss of volume under the eyes makes the eye bags more prominent than it really is. Replacement of this volume under the eyes with HA fillers can improve the appearance without the need for surgery.
However, in severe cases, surgery will be the recommended option.
Hope this helped with your queries.
All the best!