What's causing my eye bags, water retention or fat pads? (Photo)

A complete exam and review of your medical history is important in addition to your photos to answer your question. For example lower lid fullness can be caused by uncontrolled allergies (edema fluid) or hereditary (fat).A blepharoplasty is a procedure designed to improve the appearance of the eyelid area. This may involve removing excess skin and if needed tightening the surrounding muscle resulting in a more youthful, refreshed appearance. This procedure can treat both the upper and lower eyelids depending on the unique needs of the patient. Lasers and peels are often used to decrease fine lines and crepiness in addition to blepharoplasty. An exam is required to determine which procedure(s) may be best for you.

Although a more accurate diagnosis would come form an in-person office examination, it does appear that your lower eye "bags" are from exposed fat pads.  Nevertheless, there may be a portion of the "puffiness" coming from water retention.  It is very common for patients to have noticeable eyelid bags but the bags may become even more noticeable with the intake of sodium (salt), allergies, alcohol, or when you are peri-menstrual.  You can determine how much these factors are influencing your eye bags by keeping a diary of what you are consuming and critiquing your eyelid bags on a daily basis.  FYI:  Ideally keeping your sodium intake below 1500 mg per day will typically decrease water retention in this area.The following link provides more information.I hope this helps. 

This puffiness is usually due to the orbital fat pads.  IT will be worse in the morning as fluid will tend to accumulate there when you are lying down.  During the day it usually gets better.  If you have allergies, the fat can swell more due to fluid accumulation in the fat.  See an oculoplastic surgeon who can help determine how much fat you have in there and what your options are to improve it.

Is it caused by herniate fat?  There is more than one cause for lower eyelid bags.  Herniate orbital fat which is improved by lower eyelid surgery is only one of the causes.  An actual physical examination is need to determine the cause of these bags.  I recommend putting your finder on top of the lower eyelid bag.  If it is hard, you are feeling your orbital rim.  If so, you need volume in your lower eyelid hollow to fill in the hollow.  If it is soft, it is more likely that that it is herniated orbital fat that may benefit from lower eyelid surgery.  The American Society for Ophthalmic Plastic and Reconstructive Surgery maintained a geographic directory on their website that can help you find a highly qualified eyelid surgeon.

From your photo, it does appear that your eye bags are due to fat.  The bags can look bigger or smaller however, depending on a variety of factors, including water retention.  To improve this issue, you could use a filler beneath the bags to help camouflage them, or you could have surgery to directly address the fat.  

You require a direct examination to determine exactly what causes your lower eyelid bags and the proper treatment. However at your age, a filler below the area can frequently solve the problem. This is what I have done for almost all my patients your age with excellent results. See an expert injector with significant experience in the area around the eyes.