Can lower blepharoplasty cause enophthalmos & can they keep sinking further in?

The position of the eyeball globin in the eyeball socket is determined by the size of the socket in comparison to its contents.
If the socket is enlarged without compensation, such as with facial fractures the eyeball will sit deeper(enophthalmos). Likewise, if tissue is removed, this will also potentially cause the eyeball to sit deeper in the socket(second reason for enophthalmos)
Reducing the three fat pads of the lower eyelid generally does not usually cause significant enophthalmos. It can create a hollow appearance.
If you want an accurate assessment then consult with some ocular plastic surgeon in your community.
The aging process of the lower eyelid and mid face can be a bit complex. There are reversing contours with both fullness in the lower eyelid and lots of volume in the upper mid face. Sometimes mid phase volume restoration is an important part of a good treatment plan, and sometimes removing fat from the lower eyelid is more primary.
To make an assessment regarding the outcome of a plastic surgery procedure we generally need to see a complete proper set of before and after pictures.
The facial aging process continues, despite having had cosmetic surgical intervention.
This often include hollowing around the eyes.
Best,
Mats Hagstrom, MD