Hollow under orbital ligament. Is this fixable with filler? (Photo)

The hollowing you're referring to is often termed as 'tear trough' and it can become more noticeable with age due to the loss of fat and collagen in the face. Dermal fillers, particularly hyaluronic acid fillers, can be an effective treatment option to restore volume in this area and soften the appearance of these hollows.
The injection points would depend on your specific anatomy and the extent of the hollowing. Generally, the filler is carefully injected along the orbital rim (the bone under the eye) and massaged to distribute it evenly. This procedure should be performed by a skilled and experienced provider to ensure safety and effectiveness.
However, it's important to note that while fillers can improve the appearance of hollows, they may not completely eliminate them especially when you smile, as this facial movement can exacerbate the appearance of hollows.