Fat Removal Orbital Decompression Surgery?

Unfortunately, the questions you pose raise questions for us, that need better context.

Firstly, 1.5 mm of proptosis of the left eye compared to the right eye, is considered normal variation, and very few surgeons would operate on that small a difference. Trauma usually causes enopthalmos.

If you have lagophthalmos, this may be due to eyelid scarring and not due to 1.5 mm of proptosis.

FROD is a technique that is advocated in European medical fields. The volume of the orbit is 30 ml. 7 ml is due to the eyeball and a few ml attributed to the muscles. So there is about 15-20 ml of orbital fat.

Orbital fat has a purpose in the orbit. It is there to cushion the eyeball and allow for smooth eye movements generated by the extraocular muscles. In my opinion, bone reduction [laterally] is much safer with very low incidence of double vision.

If you are fixated with fat reduction, then you may have to travel to Italy. The Italian surgeons are the biggest advocated.

Good luck

Cosmetic orbital decompression is done to reduce bulgy appearance of the eyes. It is a very safe surgery when done using minimally invasive techniques by an oculoplastic specialist. See link below.

Although you do not have Graves' disease, you are asking a question that relates to a form of orbital decompression that has also been tried in Graves' disease. A quick search on Pub Med turns up some information that shows you need to discuss this question with highly specialized surgeons who are familiar with the techniques and literature.

For example, a brief literature search turns up the article below that indicates that FROD, fat removal orbital decompression, has a significant incidence of double vision or diplopia, and it is not always correctable.

Your question does not make it clear why you are seeking surgery. Is it the proptosis itself, or is the lagopthalmos (inability to fully close the eye due to trauma), or both.

If you have a post-traumatic lagopthalmos, the cause and treatment may be in the eyelid itself. For example, if you have 1.5 mm proptosis, is it the same in both eyes, but you do not have lagopthalmos in the non-traumatized eye?

Perhaps the levator mechanism is disrupted, and that may be amenable to repair or re-ihnsertion on the tarsal plate. Sometimes the use of a small gold weight under the skin of the upper lid is sufficient treatment for lagopthalmos. This is commonly done after stroke or Bell's palsy to help the eye close.

If the proptosis is cosmetic only, and you are not having problems with corneal dryness and ulceration, then you would have to consider if treatment is more risky than is worth it.

There are expert surgeons in bony orbital decompression (BROD), and this has been a well-tested operation for many years, and is capable of helping patients with much worse exopthalmos than you describe.

While it may seem appealing to have only fat removed, even if that were an appropriate operation for what is bothering you, you would need to consult, in person, with a specialist versed in bony orbital decompression and treatment of Graves' disease. 

Bull Acad Natl Med. 2003;187(9):1649-58; discussion 1659-60.
[Is incidence of diplopia after Fat Removal Orbital Decompression a predictive factor of choice of surgical technique for Graves' ophthalmopathy?].
[Article in French]
Adenis JP, Camezind P, Robert PY.
Source
Service d'Ophthalmologie, CHU Dupuytren, 2 Avenue Martin Luther King, 87042 Limoges, France. pradenis@unilim.fr
Abstract
Dysthroid orbitopathy or Graves ophthalmopathy is a frequent pathologic condition five times more frequent in females than males. The main symptoms are: proptosis, motility disorders related to eye muscles fibrosis, eyelid retraction, lagophthalmos, and finally the more severe ones: compressive optic neuropathy at the apex of the orbit, and corneal exposure. In order to reduce proptosis the classic approach is Bone Removal Orbital Decompression (BROD) either through eyelid skin, coronal, conjunctival, or endonasal approaches. Recently a new technique has been described by Olivari: Fat Removal Orbital Decompression (FROD). The purpose is to evaluate the incidence of diplopia after FROD and improve surgical indications for Graves' ophthalmopathy.

MATERIAL AND METHODS:
35 patients were included in this retrospective study (58 orbits). FROD (OLIVARI technique) was performed in all cases (23 bilateral surgery, 12 unilateral; 12 men, 23 women). All patients with optic neuropathy (severe Graves'ophthalmopathy) were eliminated because bone decompression was always performed. The ocular motility was examined before and after surgery by orthoptic screening. The average follow up was 18 months.

RESULTS AND DISCUSSION:
Before FROD, 7 patients complained of moderate or severe diplopia: all remained with diplopia after FROD. After FROD 32% developed a new diplopia: only one patient remained with diplopia after strabismus surgery or adaptation by prisms glasses. Diplopia after BROD in moderate Graves' ophthalmopathy (with indications identical to our study) is reported from 23 to 34% in previous studies.

CONCLUSION:
Diplopia after FROD is a real risk whose incidence is identical after FROD and BROD and must be explained to each patient before surgical decision.