Optic nerve sheath fenestration through a lateral canthotomy incision.

Optic nerve sheath fenestration is an increasingly useful surgical technique for relief of visual loss due to a number of optic disc pathologic conditions. To date, surgeons have employed either a medial approach with disinsertion of the medial rectus muscle or a lateral approach with removal of the lateral orbital rim to gain access to the retrobulbar optic nerve. We report herein a technique for approaching the optic nerve through a lateral canthotomy incision that does not require removal of bone or disinsertion of an extraocular muscle. It has been used to provide ready surgical exposure of the optic nerve in 17 eyes of 14 patients. This technique combines the advantages of lateral exposure of the optic nerve with an ease of operation similar to that of the medial approach.