Optic nerve sheath fenestration (ONSF), also known as optic nerve sheath decompression (ONSD), is a procedure in which the optic nerve sheath is incised directly through the medial orbital conjunctiva (or through the lateral orbital pathway, which is less commonly used) and the optic nerve sheath at the proximal end of the orbital segment or The procedure is performed by removing the 3 mm x 5 mm optic nerve sheath to allow drainage of cerebrospinal fluid through the optic nerve sheath to the retrobulbar tissue. This procedure is now well recognized abroad for the treatment of optic nerve compression due to idiopathic intracranial hypertension and is also used for other causes of intracranial hypertensive optic papilledema: for example, intracranial hypertension secondary to cryptococcal meningitis, conjunctive meningitis, intracranial hypertension secondary to intracranial sinus venous thrombosis, and neurosyphilis. Some doctors also use it for the treatment of optic nerve protection in intracranial hypertension due to intracranial tumors. Domestically, since my return to China in 2011, I have introduced this surgical protocol from the United States, and it has been carried out in Sichuan Provincial People’s Hospital for more than 4 years, with more than 100 surgeries completed, without a single death and without a single case of postoperative blindness due to the surgery, which is safe and effective. The specific surgical protocol is described as follows: General anesthesia. The conjunctiva was cut at 6:00-12:00 on the nasal side of the affected eye; the conjunctiva and Tennon’s capsule were separated, the medial rectus muscle was exposed, sutures were marked and traction was applied to the medial rectus muscle, the medial rectus muscle was broken at the muscle end point, and hemostasis was achieved; a 6-0 absorbable suture was applied to the scleral end of the medial rectus muscle and the traction line was pulled to deflect the eye to the temporal side. The posterior and parabasal orbital fat was pushed to the nasal side with an optic nerve exposer to expose the intraorbital segment of the optic nerve. Under the surgical microscope, the optic nerve sheath (dura mater) was lifted with a short alligator stirrup clamp, and the optic nerve sheath was cut with special optic nerve scissors to slowly release cerebrospinal fluid; a 3 mm × 5 mm size optic nerve sheath was excised to further release cerebrospinal fluid and prevent postoperative sphincter adhesions. The medial rectus muscle and bulbar conjunctiva were sutured and the procedure was completed. The majority of scholars believe that the mechanism of optic nerve sheathotomy is to lower the intracranial pressure and protect the optic nerve by draining the cerebrospinal fluid into the periaqueductal or retrobulbar tissue. Some scholars also believe that the anatomy of the blind end of the retrobulbar optic nerve sheath is altered, releasing the pressure in the optic nerve sheath behind the globe. Remember: the international conclusion: ONSF has improved visual function with few complications; often relieves headaches and other features. In cases of progressive vision loss where drug therapy is ineffective, ONSF should be performed as soon as possible. If chronic optic papilledema with atrophy and severe impairment of visual function has occurred, even after decompression, only residual visual function can be preserved and it is difficult to return to normal. Therefore, while intracranial pressure is under control, note that it is intracranial that is under control, not intracranial that has been controlled to normal, i.e., whether intracranial pressure is under control or not, timely and early implementation of ONSF is of great help to the patient’s intracranial pressure reduction and preservation of visual function!