A Guide To Neuro Ophthalmology

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Neuro-ophthalmology is a subspecialty and merges the fields of neurology and ophthalmology. It includes diseases of the nervous system that affect vision, eye movements, and pupillary reflexes. 60% of our brain is linked to vision. Neuro-ophthalmology requires training in problems of eye, brain, nerves, and muscles.
Some conditions seen by Neuro-ophthalmologist are not worrisome, but other problems can worsen and become life threatening. Sometimes the condition is confined to nervous system and sometimes it is related to medical condition.

Some common pathology evaluated by Neuro-ophthalmologist includes:
Afferent visual system disorders: optic neuritis, optic neuropathy, papilledema, brain tumors, and strokes.

Efferent visual system disorders: anisocoria, diplopia, ophthalmoplegia, ptosis, blepharospasm, hemifacial spasms, nystagmus, and seizures of eye muscles.

Neuro-ophthalmological Testing:
Neuro-ophthalmological testing is done to check the spectrum of Neuro-ophthalmic diseases in earliest stage. This testing involves sensory testing, visual acuity, color-vision testing, amsler grid etc.
Glaucoma is one of the major neuro-ophthalmic diseases that affect visual pathways of brain.

Preparing For The Neuro-ophthalmology Evaluation:
Make sure that your physician send all the information to the neuro-ophthalmologist including results of laboratory tests and reports of CT scan and MRI.
Bring the actual films of the CT scan and MRI to the neuro-ophthalmologist or send them in advance if you have the facility to mail.
Bring list of medications with you, including prescription.

What Happens During The Evaluation:
The neuro-ophthalmologic evaluation is the most comprehensive examination. You will be asked to tell about your current condition and your medical history including operations, medication allergies, previous hospitalization, medical problems in your family members, and serious illnesses.
A complete eye examination. This will include visual field test.
A partial or complete neurologic examination to test your sensation and coordination.
A neuro-ophthalmologist will review the results of previous scans and laboratory tests.
At the end, the neuro-ophthalmologist will tell the possible diagnosis, the need for any additional testing and treatment.

The neuro-ophthalmological examination includes both full general examination and full neurological examination.

Head And Neck Examination:
Examination of cranial nerves helps to localize the neurological lesions.
Physical signs:-
in oculomotor disturbance head tilt is seen:
-Fourth nerve palsy
-Sixth nerve palsy
-congenital nystagmus
A bruit:
-over the temple or orbit
-over the carotid
Examination of mouth:
-necrotic lesions of hard palate such as in mucormycosis
-palatal myoclonus
Examination of thyroid gland:
-enlarged thyroid gland
-a bruit may be present

Examination Of Orbits, Eyelids, And Pupils:
Presence of Proptosis can be observed by estimating the amount of sclera visible above and below the limbus. Lid retraction checked by the amount visible above the limbus. Eye lid movement is observed by measuring palpebral aperture with the eyes looking straight, up, and down. The “swinging torch test” is used to detect any afferent pupillary defect.

Examination Of Vision:
For the assessment of visual function measurement of visual acuity and visual fields is important. Ishihara pseudo-isochromatic test plate is used to assess color vision. Hardy-Rand-Ritter charts and Farnsworth-Munsell 100 hue test, both are also used for the assessment of color vision.

Examination Of Optic Fundus:
-see the shape of disc
-overall color of disc
-size of optic cup
-vascular architecture
-any evidence of disc swelling
-changes in the surrounding retina

Neuro-ophthalmological Investigations:
Computed tomography (CT)
Magnetic resonance Imaging (MRI)
CT and MRI angiography techniques
Catheter DSA
PET and SPECT
Blood tests
Lumbar puncture

Main Indications For Imaging In Neuro-ophthalmology:
The most frequent indications for a neuro-ophthalmologist to request a imaging are:
(1)Visual loss, unilateral or bilateral
(2)Anisocoria or ptosis
(3)Proptosis
(4)Ophthalmoplegia
(5)Nystagmus
(6)Papilloedema
(7)Pupillary defect.

Treatment:
Neuro-ophthalmology is non-procedural.
But they are trained to do eye muscle surgery to treat optic nerve fenestration and botulinum injectections are gives in case of blepharospasm or hemifacial spasm.

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