NEURO-OPHTHALMOLOGY deals with problems that involve the eye and brain. Neuro-ophthalmologists are either ophthalmologists, like Dr. Ing, or neurologists, that have taken extra training in the subspecialty of neuro-ophthalmology. Neuro-ophthalmic problems are usually quite complex, and it is difficult to discuss them in adequate detail using this limited amount of space, and without the reader having a medical background.
The most common neuro-ophthalmic problems include cranial nerve palsies, visual field defects, pupil problems, optic nerve disorders, Bells palsy, blepharospasm and hemifacial spasm. Neuro-ophthalmic problems are complex, and it is often difficult to restore vision after stroke or trauma. In such instances use resources such as the Canadian National Institute for the Blind (CNIB) while awaiting recovery.
Click to the LEFT of the yellow Neuro-ophthalmology button for extra information, or BELOW to connect with the patient information pages from the North American Neuro-ophthalmology Society
CRANIAL NERVE PALSY
There are 12 paired cranial nerves that emanate from the brainstem to subserve various facial function. For ease of identification, they are numbered. Cranial nerves number 3, 4 and 6 supply the extraocular muscles. Cranial nerve number 7 controls movement of the face, and cranial nerve number 5 controls sensation to the cornea and face.
The cranial nerves can be damaged by chronic high blood pressure, high blood sugar, inflammation, trauma, or infiltration, compression by tumour.
Damage to cranial nerves 3, 4 or 6 may result in double vision or diplopia.
Damage to cranial nerve 7 may result in a “Bells palsy”.
In patients with peripheral vision loss after brain injury (hemianopsia or hemianopia), it may be very difficult to restore the side vision. There are some “vision restitution” programs available (e.g. NovaVision, VisioCoach), but substantial recovery of peripheral vision is usually limited, and the programs can be expensive. “Adaptive” eye movements in to the blind field of vision, or improved motion perception are more likely to occur, than actual return of the lost visual field.
To increase peripheral awareness after hemianopsia, Dr. Ing has a free, but unvalidated EBI (Emend Brain Injury) slide program for patients to use at home.
Some patients with hemianopsia benefit from prisms. (e.g. Gottlieb or Peli.) A free website to help hemianopics to read is at http://www.readright.ucl.ac.uk/
OPTIC NERVE PROBLEMS
are neuro-ophthalmic problems that are listed separately on the yellow bar to the right.
VISUAL CORTICAL PROSTHESES
1) Dr. Daniel Yoshor: Neurosurgeon at the University of Pennsylvania
NIH-funded cortical prosthesis research program
2) Dr. Phil Troyk: Scientist at Illinois Institute of Technology will enter Phase I trials with his visual cortical device
3) Dr. Patrick Degenaar’s talk on Neuroprosthesis (Newcastle University UK)