Minimally invasive techniques are the trend in surgery today. Endoscopy has been widely used in surgical procedures of the pentatomical and abdominal organs; however, the use of endoscopy in orbital surgery has been mainly performed by pentatomists through a sinus approach. In recent years, some orbital surgeons have experimented with transorbital approaches for orbital surgery. In this paper, we present the basic situation, current application status, problems and application prospects of this technique. I. Basic information 1. History: The original medical endoscope was the gastroscope, which was initially started by Hirschowitz et al. (1958). In 1981, Norris and Cleasby were the first to describe the application of endoscopy in orbital surgery, trying to create a cavity with the help of air, but were unsuccessful. caused edema. Braunstein et al. used a soft endoscope in the dog orbit and injected hyaluronic acid through the tip to aid visualization, which produced concomitant damage during the formation of an optical cavity and prevented the formation of a safe, expandable cavity, limiting the use of endoscopy in orbital fat; therefore, transorbital endoscopic surgery has not been performed rapidly. In contrast, endoscopic surgery by pentacologists is uniquely suited to perform some orbital procedures that have been extrapolated to the transnasal and trans-sinus routes. In recent years, transorbital endoscopic surgery has gained some breakthrough from the subperiosteal space, but still cannot form a visual cavity within the orbital fat. 2. Equipment: Currently, the endoscope applied in orbital surgery is a nasal endoscope, mainly a rigid mirror, including a fiber optic illumination system with a steel tube casing and a lens system. The optical system is similar to a periscope, with the eyepiece and objective lens located at both ends of the mirror. The objective lens forms the inverse phase and the image is transmitted over the full length of the mirror, this system allows most of the light to reach the eyepiece from the objective lens. The prism is attached to the far end and varies the viewing angle from 0 to 110 degrees. The light comes from a 300W xenon light source and the image is captured by a charge couple device (CCD) television camera at the near end of the mirror, processed, and transmitted to a television monitor. Images can be recorded and printed. The most commonly used endoscope for orbital surgery is a 4 mm rigid endoscope with 0, 30 and 70 degree tips. Current status of application 1) Orbital tumors: 1) cavernous hemangioma: Tumors in the orbital apex often involve important structures around the eye, including the optic nerve, ocular arterioles, extraocular muscles and their innervated nerves. The traditional surgical approaches including transfrontal, transfrontal sieve and transmaxillary are prone to damage the normal tissues surrounding the lesion. Karaki et al. reported a case of orbital apical cavernous hemangioma resected through the septal sinus with a diameter of approximately 15 mm. There was minimal intraoperative bleeding, no skin incision, and no intraoperative as well as postoperative complications. Mir-Salim et al. and Tsirbas et al. also reported one case each of endoscopic resection of orbital apical cavernous hemangioma through the septal sinus, and both were successful with no intraoperative or postoperative complications. The nerve and blood vessels surrounding the lesion can be clearly distinguished during the trans septal sinus endoscopic procedure, avoiding surgical complications due to damage to the surrounding tissues. 2) Supraorbital wall tumors: Tumors of the orbital apex, such as eosinophilic granuloma, orbital dermatomycosis, and Langerhans’ cell hyperplasia, invade the anterior part of the supraorbital wall and are often difficult to expose near the superior orbital rim, often requiring opening the orbital bone to clearly expose the surgical field. However, with the use of a transnasal endoscope, lesions located in the anterior part of the supraorbital wall can be clearly visualized and safely removed. 3) Orbital content enucleation: Traditional orbital content enucleation is performed with eyelid preservation or eyelid removal. Batra et al. performed image-mediated surgery in two patients with sinus malignancy and one patient with fulminant, invasive orbital invasion of fungal sinusitis with combined endoscopic and soft tissue resector techniques, preserving the eyelids with minimal bleeding. The uninvolved superior and external orbital periosteum is given preservation and the cavity is mucosalized after 8 weeks. This procedure has 3 advantages: (1) direct transnasal control of the ophthalmic artery from the optic foramen; (2) preservation of the uninvolved superior and external orbital periosteum without tissue grafting or tamponade after cavity mucosalization; and (3) visual excision of the orbital lesion. 2. Orbital decompression for thyroid-related ophthalmopathy: Thyroid-related ophthalmopathy is an autoimmune disease in which lymphocytes infiltrate the extraocular muscles and the accumulation of aminoglucan in the orbital fat leads to an increase in the volume of the orbital contents. Nearly half of patients with Grave’s disease progress to having ocular symptoms. The average volume of the orbit is 26 ml, and an increase of 4 ml in the volume of the orbital contents results in a 6 mm increase in the protrusion of the eye, which leads to exposure keratitis, fibrosis of the extraocular muscles leading to strabismus, increased orbital pressure on the optic nerve leading to loss of vision, loss of color vision, and visual field loss. The first orbital lateral wall decompression was performed by Dollinger in 1911, but the reduction of orbital contents was very limited. Naffziger’s approach of decompressing the orbital contents by moving them into the anterior cranial fossa required an incision of the skull, which led to a series of postoperative complications, including meningitis due to infection and cerebrospinal fluid leakage. With the development of endoscopic techniques, endoscopic orbital decompression has become increasingly safe and efficient. Levy et al. performed endoscopic orbital decompression in five patients with Grave’s ophthalmopathy with increased orbital pressure, and the postoperative prominence of the eye was regressed by an average of 5 mm. Three of them had improved visual acuity soon after surgery. Malik et al. performed endoscopic orbital decompression to improve the appearance of 15 patients with Grave’s ophthalmopathy, and then performed a retrospective clinical study, and found that all subjects had significant postoperative regression of orbital prominence. Stiglmayer et al. retrospectively studied 32 eyes of 21 patients with Grave’s ophthalmopathy who underwent transnasal endoscopic orbital decompression due to ineffective conservative treatment and found that postoperative transnasal endoscopic orbital decompression improved visual acuity, regressed prominence, reduced intraocular pressure, and improved appearance. The diplopia and strabismus that occurred after the decompression surgery were also well resolved by the extraocular muscle surgery. The traditional orbital fracture repair incision consists of a lower lid skin incision and a transconjunctival approach. The transconjunctival approach leaves an unattractive scar on the skin surface, while the transconjunctival approach may result in 3%-42% lid ectropion. If a transnasal endoscopic procedure is used for fracture repair, there is no scarring. Transnasal endoscopic orbital fracture repair allows the surgeon to clearly visualize the size and shape of the fracture, which helps determine whether orbital fracture repair is needed. In addition, the posterior edge of the fracture and the embedded tissue are difficult to see through the traditional surgical approach, which can easily damage the infraorbital vessels, nerves, and intraorbital tissues during surgery. The use of a 70-degree endoscopic probe allows the surgeon to clearly observe the orbital fracture. All 12 patients observed by the author had a relatively satisfactory outcome. 4. Optic nerve decompression: Koc et al [18] reported two cases of idiopathic intracranial hypertension (pseudotumor cerebri) in which optic nerve decompression was performed by transnasal endoscopy; pseudotumor cerebri can easily cause an increase in idiopathic intracranial pressure, resulting in severe headache and loss of vision, which requires surgical decompression of the optic nerve when medication is difficult to control the condition. The authors mentioned in the literature that the postoperative optic nerve compression improved in these two patients, and the headache as well as the vision loss were relieved. 5. Endoscopic lacrimal sac nasal anastomosis: Since the use of endoscopy in ophthalmology, ophthalmologists have been studying endoscopic lacrimal sac nasal anastomosis via the lacrimal dots. Mullner et al. reported 32 cases of endoscopic lacrimal sac nasal anastomosis via lacrimal dots combined with ATP laser, with a maximum postoperative follow-up of 12 months and three cases of reocclusion. There is also a transnasal endoscopic lacrimal sac nasal anastomosis. The nasal endoscope allows direct visualization of the nasal tract and adjacent tissue structures, and the large surgical space allows for a higher success rate compared to transapical lacrimal sac nasal anastomosis. Transendoscopic lacrimal sac nasal anastomosis has obvious advantages over conventional lacrimal sac nasal anastomosis: better intraoperative visualization, shorter operative time, less bleeding, less tissue damage, and no postoperative facial skin incision scar formation. Some authors compared the success rate of combined lacrimal duct placement after endoscopic lacrimal sac nasal anastomosis with and without combined lacrimal duct placement, and found that there was no difference between the two, so it is believed that combined lacrimal duct placement after endoscopic lacrimal sac nasal anastomosis does not improve the success rate of surgery. 6, eyebrow sagging correction: With age, facial skin becomes saggy, eyebrows sag, forehead skin wrinkles form, people look old and emaciated. The eyebrow ptosis correction surgery and forehead surgery can improve facial appearance and make people “rejuvenated”. Since Vasconez first reported endoscopic brow ptosis correction in 1994, endoscopic brow lift surgery has become a trend because of its advantages such as small incisions, minimal damage to surrounding tissues, short operating time, and low bleeding. Kinzel et al. performed endoscopic brow ptosis correction in 61 female patients aged 36 to 64 years between 1999 and 2002, and compared the patients’ pupillary spacing, maximum distance between the eyebrows, and maximum distance between the eyebrows and the hairline before and after surgery by measuring the patients’ pupillary spacing, maximum distance between the eyebrows, and maximum distance between the eyebrows and the hairline using a scale (1-10) to evaluate the patients’ satisfaction with the improvement of their appearance after surgery The results showed that the patients’ degree of postoperative satisfaction was high and the ptosis was effectively corrected, so the authors concluded that endoscopic brow ptosis correction is an effective and less invasive way to improve appearance. Problems 1. Intraorbital cavity: A prerequisite for endoscopic surgery is the availability of a safely expandable space, such as the bladder, stomach and other organs, and the widespread use of transnasal endoscopic surgery is precisely because the nasal cavity and sinuses meet this prerequisite. However, as studied in the previous study, orbital fat hinders the development of orbital endoscopic surgery. Therefore, either a cavity is created or a potential cavity, such as a subperiosteal cavity, is used. The use of a retractor to retract the orbital tissue to create a subperiosteal space has made orbital endoscopic surgery possible, allowing us to obtain a sufficient field of view to dissect the orbital bone and expose the lesion with the help of an endoscope. However, orbital fat remains one of the obstacles to the application of orbital endoscopy, making the use of transorbital endoscopy limited. 2. Complications: Since the sinuses and orbit are closely related anatomically, some complications are inevitable with transnasal endoscopic surgery. The risk of injury depends on the anatomical variation, previous surgical history, the extent of the lesion itself and the degree of damage to the surrounding tissues, and the proficiency of the surgeon. Common complications include strabismus and diplopia due to extraocular muscle injury, loss of vision due to damage to the optic nerve, damage to the lacrimal system, and intraorbital hematoma and emphysema. The advantages of endoscopic surgery are good illumination, high magnification, small trauma and good surgical field. Therefore, whether it is transnasal endoscopic surgery or transorbital endoscopic surgery, the application of endoscopy in orbital surgery has not only solved the problem of surgical blindness in many orbital surgeries, but also changed the treatment mode and the treatment content of some orbital diseases. The endoscopic approach through the septal sinus allows for excellent visualization of the lower part of the orbit and the orbital apex. The application of endoscopy in orbital surgery is also reflected in surgical teaching, as it is known that the field of view in orbital surgery is very limited, which makes it difficult for the surgical instructor to see the surgical procedure for beginners. However, with the endoscope, the instructor can see and instruct the learner on the monitor, and can comment on the video of the procedure after the surgery. It is believed that with the improvement of optical imaging technology and the development of endoscopic surgical techniques, orbital minimally invasive surgery will be further applied.