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. female Reduced VA Pain with eye movement Colour desaturation RAPD

65 y.o. male Reduced VA Painless loss of vision Essential hypertension Smoker

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 Media Tolosa-Hunt Sy.

CVA Tumour

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 Palsies Looking 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