Neuro-ophthalmology
Dr. Abdullah Al-AmriOphthalmology Consultant
Content
• Optic nerve and visual pathway.• Visual field testing.• Ocular autonomic pathways.• Pupillary reactions• Ocular motor cranial nerves.• Ocular motility testing.
Optic nerve and visual pathway
• The optic nerve begins anatomically at the optic disc but physiologically and functionally within the ganglion cell layer that covers the entire retina.
• The optic nerve is surrounded by a sheath formed by the dura, arachnoid and pia mater continuous with that surrounding the brain.
• Signs of optic nerve dysfunction:1. Reduced visual acuity.2. Visual field defects.3. Dyschromatopsia. 4. Diminished light brightness sensitivity.
Visual field testing
• It is part of the basic ophthalmic examination.• Each eye must be examined separately.1. Confrontation field testing.2. Amsler Grid.3. Perimetry.
Confrontation field testing
Perimetry
Color vision testing
Ocular autonomic pathways
• Movements of the pupil are controlled by the parasympathetic and sympathetic nervous systems.
• The pupils constrict (miosis) when the eye is illuminated (parasympathetic activation, sympathetic relaxation) and dilate (mydriasis) in the dark (sympathetic activation, parasympathetic relaxation).
Sympathetic Pathways
Parasympathetic Pathways
Pupillary reactions
• Pupils should be examined while patient is looking at distance.
• Both pupils should be round and equal in size at first inspection.
• Swinging-flashlight test is the most valuable test for optic nerve dysfunction.
• Abnormal test called Relative Afferent Pupillary Defect (RAPD). (Marcus Gunn Pupil)
Causes of anisocoria
Ocular causes:• Posterior synechiae.• Intraocular surgery.• Blunt trauma (traumatic
mydriasis).• Drugs:i. Topicalii. Systemic
Neurological causes: • Horner’s syndrome.• A light–near dissociation.• Relative afferent pupillary
defect.• Adie’s pupil.• Argyll Robertson pupil.• Coma.
Horner’s syndrome
Signs: • Interruption of the
sympathetic pathway.• A small pupil on the affected
side.• A slight ptosis on the affected
side.• Lack of sweating on the
affected side.• Heterochromia (congenital
Horner’s).
Causes: • Because of its extended
course the sympathetic pathway may be affected by a multitude of pathologies:
I. Syringomyelia.II. Disease of the lung apex.III. Neck injury, disease or
surgery.IV. Cavernous sinus disease.
The swollen optic disc
Papilledema due to raised intracranial pressure
History:• Young female.• Obscurations of vision.• Headache.• Nausea.• Diplopia. • neurological symptoms.• history of head trauma
suggesting a subdural hemorrhage.
Signs: • The optic disc is swollen.• No spontaneous venous
pulsation of the central retinal vein.
• A large blind spot will be found on visual field testing.
• Abnormal neurological signs may indicate the site of a space-occupying lesion.
Optic neuritis
• Inflammation or demyelination of the optic nerve results in optic neuritis.
• An acute loss of vision.• Pain on eye movement.• Other neurological
symptoms to suggest a diagnosis of demyelination (multiple sclerosis).
• Signs: • Reduced visual acuity.• Reduced color vision.• Relative afferent pupillary
defect (RAPD).• Central scotoma on field
testing.• A normal disc in
retrobulbar neuritis. • A swollen disc in papillitis.
Ocular motor cranial nerves
Ocular motility testing
• Eye movement should always be examined, especially if the patient has a complaint of double vision or if any neurologic disease is suspected.
• All nine ocular positions should be examined carefully.
Third cranial nerve palsy
Fourth cranial nerve palsy
Sixth cranial nerve palsy
Questions
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