Fibrous Dysplasia Fibrous dysplasia, craniosynostosis, mucopolysaccharidosis and osteopeterosis can cause optic foraminal narrowing and optic atrophy. Sometimes, these compressions can be unilateral or asymmetrical. In the case of craniosynostosis, intracranial pressure may be elevated and papilledema can of itself cause optic atrophy. Digre, Corbett A young man with a right optic neuropathy -- notice the difference between the two discs -- (OD--A; OS--B) from compression of the right optic canal due to fibrous dysplasia shown here with CT axial (C) and coronal (D). The arrows point to dysplastic bone of the optic canal Top: axial CT, bone windows Bottom: coronal CT