Möbius syndrome. Electron microscopic study of the extraocular muscles

The medial rectus, external rectus and inferior oblique muscles were examined by electron microscopy in Möbius syndrome. The electron microscopic findings of the medial rectus and inferior oblique were of degenerative and inflammatory nature, whereas the lateral rectus showed complete fibrosis. The fibrotic lateral rectus could explain the absence of abduction in Möbius syndrome.