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