Reason 1: Complexity of orbital disease Orbital tumors are of many kinds, and there are more than 100 primary tumors in the orbit alone, and due to the different pathological properties of tumors, their texture and toughness of the envelope are also different, and the methods of removing lesions during surgery are also different. Therefore, any damage to any of the blood vessels, nerves or muscles will affect the function of the eye, resulting in drooping eyelids in mild cases and blindness in severe cases. Therefore, when performing orbital tumor removal, we should not only be familiar with the local anatomy of the orbit to avoid damage to the normal structures, but also be aware of the relationship between the tumor and the adjacent orbital structures to prevent serious complications; at the same time, mastering the corresponding surgical techniques and choosing the appropriate orbital surgical approach according to the location and nature of the tumor is also the key to successful completion of the surgery. Reason 2: Requirement of surgeon’s experience Orbital surgery is one of the most complicated surgeries among all ophthalmic surgeries and requires a high level of surgeon’s experience. Since the lesions are sometimes extra-orbital and often require the cooperation of neurosurgeons and otorhinolaryngologists, the requirements for anesthesia are very high, so a general hospital is more appropriate, preferably an orbital surgeon. Of course, the doctor must be familiar with the orbital anatomy and must have a comprehensive knowledge of oncology and imaging. This means that the doctor must be trained in the specialty, but of course, the doctor’s own efforts and diligence are indispensable. Reason 3: Correct choice of surgical incision Experienced orbital specialists attach great importance to the choice of surgical incision, and the wrong choice often leads to the inability to remove the tumor. The incision skin incision should be in line with the skin line so that the postoperative scar is more aesthetic or less obvious. When choosing an incision under the arch of the eyebrow, it should be slightly curved to coincide with the lower edge of the eyebrow; the curvature of the skin incision above the inner and outer surface should be large, and the incision should be made along the orbital rim; the “S” shaped modified incision should not be at a right angle when turning the orbital skin incision; the incision under the eyelashes should be 1 mm below the eyelashes, and if the tension is high, the incision can be made 1 cm below the outer canthus. The conjunctival incision is mostly chosen near the fornix according to the situation, but the superior fornix and the external superior fornix are contraindicated. The incision is likely to cause ptosis and damage to the lacrimal system. Reason 4: Tumor stripping The following principles should be followed in stripping surgery: 1) As far as possible, blunt and sharp stripping should be combined. When the tumor has an envelope (benign pleomorphic adenoma of the lacrimal gland, nerve sheath tumor), it is appropriate to peel along the tumor envelope to reduce the damage to normal structures. 3. When the lesion is attached to the optic nerve or other nerves or blood vessels, it should be peeled off under direct vision. 4. When stripping malignant tumor, it should be stripped in the normal interface outside the tumor and the tumor should be completely cut. Reason 5: Removal methods of tumor Removal of orbital tumor is different in texture and nature, and the removal methods are also different. Tumors with tough texture, such as cavernous hemangioma, inflammatory pseudotumor with more fibrous tissues, meningioma, etc., can be separated and removed after clamping with tissue forceps; 2. Tumors with brittle texture, such as benign pleomorphic adenoma of the lacrimal gland, can only be removed by clamping the periosteum around the lesion, otherwise the tumor will be broken and cause recurrence. For tumors such as nerve sheath tumors, the tumor should be removed completely or intracapsularly as possible, i.e., the tumor content should be scraped off and then the cystic membrane should be removed (only some nerve sheath tumors allow intracapsular removal); 4. For certain cystic tumors such as mucinous cysts, dermatoglyphic or epidermoid cysts, during the removal process, the cystic fluid should be aspirated after most of the cysts are separated as a whole (sometimes premature aspiration of the fluid causes difficulties in separation of the posterior part of the lesion), and then the cystic membrane should be removed under direct vision; 5. The tumor can be removed at one time, such as benign pleomorphic adenoma of lacrimal gland, nerve sheath tumor (there are two kinds of nerve sheath tumor, one can be excised intracapsularly and the other must be excised as a whole), etc. This method is needed to remove the tumor and cannot be excised in pieces; 6. Some tumors cannot be completely excised for various reasons (or the complete excision may cause serious combination of evidence) can be partially excised (or volume reduction), such as cavernous hemangioma, inflammatory pseudotumor, vascular malformation, lymphangioleioma, etc. with serious adhesions. Commonly used approaches for orbital surgery include anterior orbital surgery, lateral orbital surgery, medial orbital surgery, combined medial and lateral orbital surgery and transcranial orbital surgery.