Are fluid sacs under eyes appearing 10 years post blepharoplasty reversible? (Photos)

First, these are not "fluid" sacs or bags.  These are a type of festoon which is a result of laxity of tissue glide planes normally found in this area.  So no, they can't be "drained." Have you every had hyaluronic acid filler in this area?  As it ages, it can look exactly like this.  In that case, the treatment is injecting the area with the enzyme that brakes down the old hyaluronic acid filler. There is no substitute for a personal consultation.

You have the beginnings of festoons, which are hard to treat. I would recommend surgical excision, if possible, plus laser resurfacing and microneedling to help improve the quality of the skin. What you cannot fix with treatment you can camouflage with a hyaluronic-acid based dermal filler, such as Restylane Silk. I hope this helps.

This is fluid retention in the thin skin and underlying fat pad.  When it gets larger we call it a festoon.  THese are very hard to eliminate.  Surgery to excise skin will sometimes help if there is sufficient skin to remove.  Laser resurfacing can also help for some people.  But can be tough to get rid of!  

As the other MD's have mentioned, your under eyelid bags are actually called festoons. These are from redundant muscle and skin. You can try lasers, fillers, or fat to camoflauge them, but the definitive treatment for these is direct excision. When performed by a plastic surgeon the scarring is minimal.

These look like malar bags, otherwise known as festoons. Anything causing fluid retention around the eyes will make them worse, such as allergies or increased salt intake. They can't be drained because the fluid is dispersed throughout the skin. They are most commonly hereditary and are likely not related to your lower lid blepharoplasty. Malar bags are difficult to treat and treatment is either surgical excision of the skin which can leave a (usually acceptable) scar or laser to tighten the skin overlying them.