A: Peritomy is performed, B: Isolation of the medial rectus muscle, C: The muscle is detached from the globe, D: Lateral retraction of the globe, E: The orbital fat is retracted away from the optic nerve, F: Incision of the optic nerve sheath, G: Extension of the incision to a total length of 3 to 5 mm, H: The medial rectus is reattached and the peritomy is closed. Image adapted adapted from [1].