There are two main types of orbital decompression surgery: orbital wall decompression surgery and orbital fat decompression surgery. Orbital wall decompression surgery can be performed by removing the orbital wall to expand the volume of the orbit, effectively improving the protrusion of the eye and relieving orbital crowding. Orbital fat decompression surgery can be performed by removing orbital fat tissue to achieve decompression and improve orbital protrusion to some extent. Orbital fat decompression surgery can achieve decompression by removing orbital fat tissue and improve orbital protrusion to some extent. Orbital fat decompression surgery can be performed through a hidden incision in the conjunctiva (red line) to remove fatty tissue in the superior, medial, inferior, and inferior external parts of the orbit (yellow). The upper outer fatty tissue (blue) not only requires a skin incision, but is not recommended for decompression purposes! In 1920, Moore first described simple orbital fat decompression surgery. Starting in the 1980s, Olivari began to apply and popularize orbital fat decompression surgery, first reporting 9 cases of orbital fat decompression surgery in Germany and then reporting a large sample of 75 cases (147 eyes) in a study with a mean protrusion regression of 5.9 mm and some degree of improvement in all patients with preoperative diplopia, with a 55% complete improvement in diplopia.Olivari’s large sample study showed that 14.3% of patients developed new permanent diplopia and another 57% of patients without preoperative diplopia developed transient transient diplopia (up to 6 months postoperatively). However, subsequent reports did not yield similar results. Trokel reported no surgically induced permanent diplopia or any worsening of ocular motility in any of the 158 eyes in 81 orbital fat reduction procedures, with a general regression of 1.8 mm in proptosis and a regression of 3.3 mm in patients with preoperative proptosis greater than 25 mm. Adenis reported better improvement in proptosis than In 2003, Adenis performed orbital fat reduction using Olivari’s method, but the recurrence rate of recurrence was even 32%. Thus, the incidence of diplopia is similar for orbital fat decompression and orbital bone wall decompression. In a more recent study of 222 Asian patients with thyroid-related eye disease who underwent orbital fat decompression through a “cycloplegic eyelid” approach, the rate of new recurrences of diplopia was only 2% and 20% of preoperative diplopia was cured, which was encouraging in terms of control of oculomotor impairment. Of course, there were differences in surgical protocols and patient ethnicity compared to previous studies. In parallel with the Asian study, Olivari reported a landmark case series of 2,697 patients in a 20-year study of orbital fat reduction through the eyelid approach. The improvement in ocular prominence was similar to that reported earlier, however, the rate of new recurrences of diplopia requiring surgical or prismatic correction reached 22.2% at 6 months after surgery. Although previous studies have had mixed findings in terms of both improving ocular prominence and affecting oculomotor function, overall, orbital fat reduction surgery is a safe treatment option to improve not only visual function but also high intraocular pressure. In particular, orbital fat reduction surgery is highly effective for facial disfigurement caused by protrusion of the eye and orbital fat prolapse due to moderate to severe ophthalmopathy with increased fat.