Supplementary Material for: Transsphenoidal Optic Canal Decompression to Manage a Venous Malformation of the Optic Canal: Case Report

Introduction
Intracanalicular vascular malformations are rare. This report describes a case of compressive optic neuropathy secondary to an intracanalicular venous malformation managed with endoscopic transsphenoidal optic canal decompression.

Case presentation
A 43-year-old female presented with an 18-month history of painless vision loss secondary to an intracanalicular venous malformation causing compressive optic neuropathy. Ophthalmic examination showed reduced visual acuity and color vision, relative afferent pupillary defect, and optic disc pallor. Imaging findings were consistent with a slow flow vascular malformation. An endoscopic transsphenoidal optic canal decompression was performed. The lesion was found to be wrapping around the optic nerve. At follow up after one-year, visual acuity had improved along with restoration of full color vision and visual fields.

Conclusion
This case highlights the successful use of endoscopic transsphenoidal optic canal decompression to treat compressive optic neuropathy caused by an intracanalicular venous malformation.