Lecture from RCSI on neuro-ophthalmology

1. NEURO
OPHTHALMOLOGY
Dr Geeta Lal
RCSI

2. NEURO OPHTHALMOLOGY
 Topics covered in this lecture are:
 Pupillary disorders
 Neuro motility disorders
 Optic nerve disease
 Visual field defects

3. PUPILLARY PATHWAYS
Anatomy and physiology
 The iris controls the size of the pupil. It contains
two groups of smooth muscle fibres:
 Sphincter pupillae innervated by the parasympathetic
nervous system
 Dilator pupillae innervated by the sympathetic
nervous system
 Pupil size (normal 2-6 mm) depends on the
balance between sympathetic and
parasympathetic tone

4. PUPILLARY DISORDERS
Anisocoria
 = unequal pupils
 A 1-2mm difference in pupil size can be physiological
 Check in bright and dark room to ascertain which pupil is
abnormal
 If one pupil is abnormally constricted the anisocoria will increase
when lights dimmed
 If one pupil is abnormally dilated the anisocoria will decrease
when lights dimmed
 Physiological anisocoria will remain unchanged

5. ANISOCORIA
Dilated pupil

6. Mydriasis
 = dilated pupil
 Causes
 3rd nerve palsy
 Adies pupil
 Pharmacological
 Trauma
 Acute glaucoma

7. Miosis
 = constricted pupil
 Causes
 Horner’s syndrome
 Pharmacological
 Iris abnormalities (e.g. posterior synechiae)
 Painful inflamed eye e.g. iritis, keratitis
 Argyll Robertson pupil

8. Horner’s syndrome
 Lesion of the sympathetic pathway in head and
neck
 Miosis, ptosis and anhidrosis
 Myriad of causes including Pancoast apical lung
tumour
 Diagnosis
 Cocaine drops dilate normal pupil but not Horner’s
pupil
 Hydroxyamphetamine drops locate the lesion as pre-
ganglionic (dilates pupil) or post-ganglionic (does not
dilate)
 Further investigations directed by history and exam

9. Relative afferent pupillary defect
 Caused by optic nerve lesion or severe
retinal damage, i.e. a lesion anterior to
optic chiasm
 Can be elicited by SWINGING FLASH
LIGHT TEST
 If the light source is “swung” from eye to eye,
dwelling 2-3 secs on each, the affected pupil
will paradoxically dilate

10. Adies pupil
 Unilateral dilated pupil
 Benign condition usually affecting young women
 Onset is acute and may cause blurring
 Absent light response; response to
accomodation slow but present = light near
dissociation
 If associated with reduced or absent limb
reflexes = Holmes Aides syndrome
 No known cause

11. Pharmacological anisocoria
 Miosed pupil
 Pilocarpine
 Opiates
 Dilated pupil
 Atropine (systemic or eye drop)
 Cyclopentolate
 tropicamide

12. Argyll Robertson pupil
 Pupils irregular, small and difficult to dilate with
drops
 Seen in neurosyphilis
 Light near dissociation present
 Near response present, light response absent

13. NEUROMOTILITY DISORDES
Related anatomy and physiology
 Six muscles control eye movements:
1. Superior rectus
2. Medial rectus
3. Inferior rectus
4. Inferior oblique
(All the above muscles innervated by the 3rd nerve)
5. Superior oblique - innervated by 4th nerve
6. Lateral rectus - innervated by the 6th nerve
 The oblique muscles move the eye up (Inferior oblique) or down (superior
oblique) when it is turned in
 The superior and inferior recti move the eye up (SR) and down (IR)
 The lateral and medial recti abduct (move out) and adduct (move in) the eye
respectively
 Eye movements are examined in the six different directions of gaze
representing individual muscle action

14. Third nerve palsy
Clinical features:
 Ptosis
 Eye down and out
 Limited elevation, adduction and depression
 Pupil sparing or pupil involving (pupil fixed and
dilated)
 Pupil involving third nerve palsy = PCA
aneurysm until proven otherwise. Life
threatening neurosurgical emergency

15. Third nerve palsy
Causes
- Idiopathic
- Microvascular disease (diabetes,
hypertension)
- Posterior communicating artery aneurysm
- Head trauma
- Tumours

16. SIXTH NERVE PALSY
Clinical features
 Esotropia (convergent squint) in the primary
position, due to unopposed action of the medial
rectus muscle
 Marked limitation of abduction
 Horizontal diplopia (double vision)

17. SIXTH NERVE PALSY
Causes
 Microvascular disease (diabetes, hypertension)
 Raised intracranial pressure
 Acoustic neuroma (cerebellopontine angle
tumour)
 Nasopharyngeal tumours
 Trauma (basal skull fracture)

18. FOURTH NERVE PALSY
Clinical features:
 Affected eye is hypertropic, i.e. at higher position
than the unaffected eye
 Hypertropia increases on tilting the head to the
ipsilateral shoulder
 Vertical diplopia
 Patient adopts a compensatory head tilt to the
opposite side to prevent diplopia

19. FOURTH NERVE PALSY
Causes:
 Congenital – may not develop until adult life
 Acquired
 Trauma
 Microvascular disease
 Aneurysms and tumours rare

20. Myasthenia gravis
 Autoimmune disorder of the
neuromuscular junction
 Systemic and ocular features
 Ptosis, ophthalmoloplegia and weak
orbicularis muscle
 Fatigable, asymmetrical, variable
 Tensilon test confirms diagnosis

21. OPTIC NERVE DISEASE (OPTIC
NEUROPATHY)
 CONGENITAL
 ACQUIRED
 Inflammatory (optic neuritis)
 Vascular (ischaemic) optic neuropathy
 Arteritic (Giant cell arteritis) or Non arteritic
 Compressive optic neuropathy (tumours)
 Infiltrative/granulomatous optic neuropathy (Sarcoidosis, Leukemia )
 Trauma
 Toxic optic neuropathy, e.g. methyl alcohol
 Nutritional, e.g. vitamin B12 deficiency
 Drug induced, e.g. Ethambutol
 Radiation optic neuropathy
 Hereditary optic neuropathy (Lebers)

22. OPTIC NERVE DISEASE
Clinical signs
 Reduced visual acuity
 Relative afferent pupillary defect
 Abnormal colour vision
 Red desaturation
 Visual field defect

23. OPTIC NEURITIS
 Inflammatory optic neuropathy commonly due to
demyelination (i.e. multiple sclerosis)
 Symptoms
- Sudden loss of vision with recovery over 6-12 weeks
- Painful eye movements
 Signs
- Reduced visual acuity
- Impaired colour vision
- RAPD
- Visual field defect – variable
- Optic disc may be normal or swollen
- Visually evoked responses show increased latency

24. OPTIC NEURITIS
Swollen disc

25. ANTERIOR ISCHAEMIC OPTIC
NEUROPATHY
1. Arteritic
 Giant cell arteritis causes occlusion of
posterior ciliary arteries of optic nerve
 Untreated can cause sudden bilateral
blindness
 Never miss this diagnosis
2. Non-arteritic

26. Giant cell arteritis
 Occlusive vasculitis of ophthalmic artery and its
branches
 Elderly
 Symptoms
 Bilateral irreversible visual loss if untreated
 Temporal tenderness
 Jaw claudication
 Scalp tenderness
 Headache
 Constitutional symptoms, eg weight loss, anorexia
 Signs
 Variable visual acuity but often severe vision loss
 Pale optic disc with diffuse edema and haemorrhages
 later optic atrophy
 Thickened non pulsatile temporal artery

27. Giant cell arteritis
Investigations (urgent)
 ESR raised > 60 mm/hr (normal = half the age for men
and half the age plus 10 for women)
 C reactive protein (CRP) raised
 Temporal artery biopsy - histology confirms diagnosis
Treatment
 Aim is to prevent blindness in the fellow eye
 Initial treatment is with high dose intravenous
methylprednisolone then oral prednisolone 60 mg
daily.Taper oral steroids gradually

28. Non arteritic anterior ischaemic
anterior optic neuropathy
Clinical features
- Age group affected usually is 45-65 yrs
- Altitudinal visual field defect
- Visual loss of variable degree
- Swollen optic disc with edema /splinter haemorrhages
- Normal ESR and CRP
- Hypertension
Treatment
- Treat underlying vascular disorders (Hypertension ,
Diabetes,Hyperlipidemia )
- Aspirin to prevent further vascular events

29. Papilloedema
Bilateral optic disc swelling due to
raised intracranial pressure
Clinical features
- Visual acuity usually normal
- May be associated with transient visual loss
- Enlargement of the blind spot
- Swollen discs
- Optic atrophy if chronic

30. Acute papilloedema
s
Flame shaped haemorrhages
Cotton wool spots
Engorged retinal veins

31. Chronic papilloedema
Pale waxy disc

32. PAPILLOEDEMA
Causes
-Intracranial space occupying lesions, e.g. tumour,
Haemotoma
-Any lesion causing hydrocephalus in adults e.g..
Meningitis and subarachnoid haemorrhage
- Venous obstruction caused by thrombosis in the venous
sinuses
- Benign intra cranial hypertension
Differential diagnosis
- Malignant hypertension (always check blood pressure)

33. OPTIC NERVE DISEASE
Optic atrophy
- Caused by damage to the nerve fibres at
any point between the ganglion cells of
the retina and lateral geniculate body
- Irreversible loss of vision

34. OPTIC ATROPHY
pp
a
Pale disc and thinned retinal vessels

35. OPTIC ATROPHY
Causes
1. Retinal
Central retinal artery occlusion
Retinitis pigmentosa
2. Optic nerve
Anterior Ischaemic optic neuropathy
Optic neuritis
Glaucoma
Chronic papilloedema
Toxic e.g. Methyl alcohol, ethyl alcohol, tobacco and ethambutol.
Tumour e.g. optic nerve glioma or meningioma
Trauma
Leber’s Hereditary optic neuropathy
3. Chiasm
Any cause of chiasmal compression e.g. pituitary adenoma, craniopharyngioma

36. VISUAL FIELD DEFECTS
 Central scotoma
 Characteristic of most optic nerve lesions, e.g. optic neuritis
 Arcuate scotoma
 The scotoma extends from the blind spot above or below fixation
following the course of nerve fibres. Characteristically seen in
glaucoma.
 Bitemporal hemianopia
 Loss of temporal half of the visual field bilaterally. Seen in chiasmal
compression by tumours, e.g. pituitary adenoma
 Homonymous hemianopia
 Any visual pathway lesion posterior to the optic chiasm, e.g. stroke,
tumour

37. VISUAL FIELD DEFECTS
Left homonomous
hemianopia
Bitemporal hemianopia
Monocular blindness
Monocular constricted field
e.g. retinitis pigmentosa
Right nasal field defect,
usually due to retinal
disease or glaucoma