Under Eye Bags; Fluid Retention? Fat?

Let's take a look at your issues one step at a time. First, you are young and have healthy skin. Next, you have a roll just under your lash line--this is thickened eye muscle that is nicely treated with 1-2 units of Botox. Under that you have a crescent of fat. Fat is very sensitive to fluid levels but that is not the cause of your fat prominence--it's just your anatomy. The bags can look larger when you are retaining fluids, but returning to normal fluid status will not make the fat pads go away. The would either need to be removed surgically, or camouflaged with fillers.Under that, you have a prominent orbital bony rim with ligamentous attachments up to the skin. These findings are characteristic of volume loss and/or aging and can accentuate a triangular fat pad seen laterally.I think you could be treated either with fillers and Botox or surgical fat removal coupled with autologous fat transfer to the lower lids and midface. 

There are many causes of eye bags. Some are shadow issues (fat, ligaments, skin), some are discoloration issues.  Most people have a multifactorial issue meaning they have more than one problem causing this demarcation. Below is a short list of issues and my treatment process for each. 

1. Prolapsed orbital fat through the orbital septum: You are right this is one of the most common causes. Normally in people in an older age group than you though. It is treated with lower lid blepharoplasty and fat transpositioning. Can also be helped with fillers or auto fat transfer to the face but the ideal treatment in my hands is surgery for this issue.

2. Eczema: much more common in young people with fair skin. The treatment for this is to hold off on makeup and any manipulation of the lower lid for a few weeks and try some topical anti inflammatory creams. If you have allergies those should be treated also.  A dermatologist is the best person to see for this. We have a multidisciplinary clinic with myself, a plastic surgeon, and my partner, a dermatologist which I think is ideal!

3. Fluid accumulation and/or redundant skin. Could be possible in young patients but would need a good facial analysis and exam to determine. A low salt diet (< 1000mg/day) and a warm compress can help.  I would consider treating with filler/fat transfer, lower lid fractional ablative laser and/or lower lid blepharoplasty.

4. Descent of midface cheek pad. This then causes the nasojugular ligament to become more prominent creating a demarcation and separation of the eye from the cheek subunit. Treated with mid face lift and/or fat transfer.

It is all about the balance of this transition from the orbit to the cheek. There are many ways to treat this and they vary by the underlying cause. I recommend seeing a surgeon who also does a lot of these treatments. This can make a big difference as most people have a combination of the above that lead to the issue.

Hope this helps.

Best of luck,

DrC

Best way to determine the etiology is with an in person exam but it appears you have a combination of issues.  You seem to have some degree of lower lid fat prolapse, you have a deep tear trough, and your mid-face (cheek region) appears to be deflated.  Sometimes some filler/fat in the tear trough cheek areas help enough at a young age.  It depends on the degree of the problem.  Sometimes a combination of treatments works best.  Find someone you trust who is proficient in both surgery and filler and get their opion.  GOod Luck!