Eyes as Gateways for Environmental Light to the Substantia Nigra: Relevance in Parkinson’s Disease
Figure 4
CT and MRI analysis of a human head to trace a possible pathway for light from the outside to the substantia nigra. (a) Human head 3D CT scan showing the large superior orbital fissure that gives access to the internal cavity of the skull. (b) Sagittal CT scan of a human head. It is evident from this prospective that the mesencephalon (indicated by the white ellipse) is behind the orbit, not hidden by the posterior clinoid process. (c) Axial MRI scan of a human head. This image shows that CSF occupies a large volume between the superior orbital fissure and the mesencephalon. Furthermore, CSF is present around the optical nerve in the intraconal space. The white line indicates the estimated distance (79.78 mm) between the cornea and the mesencephalon.
