You have a combination of two things going on.... First, you have a heavier brow which will have the tendency to cause this line. This would explain the indentation you describe when your facial muscles are at rest. Second, you may have a strong procerus muscle, which pulls the brow down and accentuates this crease. If this line occurs primary when frowning or scowling, it may be improved with some Botox or similar medicine. If the line is present at rest, I would consult with a dermatologist, plastic surgeon or facial plastic surgeon for possible corrective procedures. Fillers such as restylane may be used here off label but there are increased risks due to the way blood vessels are arranged in this location on the face. Only see a very very experienced injector if this is the route you choose to pursue. Good luck!