Video of the partial optic nerve transection procedure.

Make an incision and pull the skin back over the eye, stretching the connective tissue. Use blunt-ended scissors to push against the bony orbit, clearing connective tissue and creating an opening.

Extend the opening through facial muscle and connective tissue using a push-pull technique. Identify and carefully cut the ligament attachment to the lacrimal gland while avoiding blood vessels, then push the gland aside.

Identify the extraocular muscles beneath the lacrimal gland and gradually cut them with scissors while avoiding the large blood vessel on the left side. Remove both muscle layers to expose the deeper lacrimal gland lobes.

Gently tease apart the two lobes of the deeper lacrimal gland while preserving blood vessels in the ligament. Carefully remove surrounding connective tissue to expose the optic nerve.

Insert a fine cotton wool sling beneath the optic nerve using forceps with a push-pull movement, avoiding excessive force. Ensure the nerve is correctly positioned without twisting, as verified by straight blood vessels on the surface.

Under increased magnification, use fine forceps and scissors to carefully remove the meningeal membranes surrounding the nerve while avoiding blood vessels. Work methodically along the nerve to expose it fully.

Hold the diamond knife vertically and draw the blade across the exposed nerve with minimal downward pressure while supporting the nerve with forceps or cotton sling. Create a controlled transection of the nerve.

Remove the cotton sling by cutting it close to the nerve and pulling out remaining fibers. Push the lacrimal gland back over the nerve, clean any residual tissue or fibers, and prepare the skin edges for suturing.