NEURO-OPHTHALMOLOGY

Clinical Examination

• Visual Acuity• Colour Vision• Visual Fields• Pupils

Normal Eye and Optic Disc

Cupped disc

The swollen optic disc

•Papilloedema

•Papillitis

•Malignant hypertension

•Ischaemic optic neuropathy

•Diabetic optic neuropathy

•CRVO

•Intraocular inflammation

25 y.o. femaleReduced VAPain with eye movementColour desaturationRAPD

65 y.o. maleReduced VAPainless loss of visionEssential hypertensionSmoker

The pale optic disc •Congenital

•Secondary to

•raised ICP

•vascular retinal disease

•optic neuritis

•optic nerve compression

•trauma

•Glaucoma

Papilloedema• Disc swelling secondary to raised ICP• Headache

– Worse in the morning– Valsalva manouver

• Nausea and projectile vomiting• Horizontal diplopia (VI palsy)• Causes

– Space occupying lesion– Intracranial hypertension

• Idiopathic• Drugs • Endocrine

– Severe hypertension

Haemorrhages

CWS

Blurred optic disc margin

Small optic cup

Disc pallor

Vessel attenuation

Pupils

• First Order – Retina to Pretectal Nucleus in B/S (at level of Superior colliculus)• Second Order – Pretectal nucleus to E/W nucleus (bilateral innervation!)• Third Order – E/W nucleus to Ciliary Ganglion• Fourth Order – Ciliary Ganglion to Sphincter pupillae (via short ciliary nerves)

Pupil

• Constricted (mioisis)– Sympathetic

(pupillodilator) denervation

– Drugs• Pilocarpine• Morphine

• Dilated (mydriasis)– Parasympathetic

(pupilloconstrictor) denervation

– Lesion of the third CN– Drugs

• Atropine• Cocaine

Horner’s

• Oculosympathetic paresis

– Ptosis– Miosis– Ipsilateral anhidrosis– Does not dilate with

cocaine 4%

Sympathetic Pathway• First Order – Posterior Hypothalamus to Ciliospinal centre of Budge (C8-T2) (Uncrossed in Brainstem)• Second Order – Ciliospinal centre of Budge to Superior Cervical Ganaglion• Third Order – Superior Cervical Ganglion to dilator pupillae muscle. (Close to ICA and joins V1 intracranially)

Pancoast bronchogenic carcinoma

Otitis MediaTolosa-Hunt Sy.

CVATumour

Internal Carotid Dissection

Herpes Zoster

Causes of Horner’s pupil• Central – B/S lesions (tumours, vascular and MS) Syringomyelia, Lat. Med. Syn., S.C. ca.• Preganglionic – Pancoast tumour, Carotid & Aortic aneurysms, Neck lesions/trauma.• Postganglionic – Cluster headaches, Nasopharyngeal tumours, Otitis media, Cavernous sinus mass and ICA disease.• Miscellaneous – Congenital (brachial plexus injury) Idiopathic.

• Argyll-Robertson pupil– Small, irreg– Does not react to light – Reacts to

accommodation– Causes

• syphilis• diabetes

• Miotonic pupil (Adie’s syndrome)– Dilated– Poor response to light and

convergence.

• Constricts with weak Pilocarpine

• Holmes-Adie syndrome– Reduced tendon reflexes

(Knee, ankle)- Orthostatic hypotension

Afferent & efferent defects

Ocular motility abnormalities

• Third nerve palsy– Double vision– Eye turned down & out– Ptosis– Dilated pupil &

headache• Compressive lesion

• Sixth nerve palsy– Double vision – Eye turned in

Cranial Nerve PalsiesLooking straight ahead

Posterior communicating artery aneurysm

III CN

Posterior cerebral artery

Chiasma

Internuclear Ophthalmoplegia• Defective adduction of the

ipsilateral eye • Nystagmus of the contralateral

(abducting) eye • NORMAL CONVERGENCE• Causes

– Young patients• Bilateral • Demyelination

– Older patients• Unilateral• Vascular, tumours

Myasthenia Gravis

• Fatigability• Double vision• Lid twitch• Ptosis• Normal reflexes & sensation

INVESTIGATIONS MG

• Anti ACh receptor Ab’s• Electromyography• Tensilon test

– Edrophonium blocks acetyl-cholinesterase

– Beware of cholinergic cardiac effects. Use with Atropine 0.6mg

• Thoracic CT and MRI to rule out thymoma

Anti AChR Ab’s

AChR

ACh

Localising the lesion

• Monocular visual field defects indicate lesions anterior to the optic chiasm

• Bitemporal defects are the hallmark of chiasmal lesions

• Binocular homonymous hemianopia result from lesions in the contralateral postchiasmal region

• Binocular quadrantanopias reflect optic tract lesions