Neuro

Neuro - Ophthalmology

Marwan Salah Salman MD
Pupil

Clinical examination

1.Observation
Pupil size
Anisocoria
Pupil shape ,position and number
Ptosis
Horners syndrome parinauds syndrome
2.Light reflex
Direct and consensual light reflex
Relative afferent pupillary defect
3.Near response
4.Ocular movement
5.Slitlamp examination


Afferent pupillary defect
An absolute APCD (amaurotic pupil ) is caused by complete O.N lesion and is characterized by the following :
The involved eye completely blind i.e no light perception
Both pupil are equal in size
When affected eye stimulated by light neither pupil reacts but when normal eye is stimulated both pupils react normally
The near reflex is normal in both eyes
Relative afferent pupillary defect (marcus gunn pupil ) caused by incomplete optic nerve lesion or sever retinal disease the clinical feature are those of amaurotic pupil but more subtle .
The difference between pupillary reaction is highlighted by swinging flashlight test

Light-Near dissociation

Here the light reflex is absent or sluggish but the near response is normal .
causes
unilateral
Afferent conduction defect
Adie pupil
Herpes zoster ophthalmicus
Aberrant regeneration of third nerve
bilateral
Neurosyphilis
Type 1 diabetes
Myotonic dystrophy
Familial amyloidosis
Encephalitis
Chronic alcoholism
Argyll Ropertson pupil
This is caused by neurosyphilis and characterized by following:
Involvement is usually bilateral but asymmetrical
The pupils are small and irregular
Light near dissociation
The pupil very difficult to dilate


Adie pupil
Caused by denervation of post ganglionic supply to sphincter pupillae and ciliary muscle , which may follow viral illness characterized by the following :
Involvement is 80% unilateral
The pupil large and regular
Light near dissociation
Accommodation may manifest similar tonicity
In some cases are diminished deep tendon reflexes (holm –adie syndrom ) and autonomic nerve dysfunction
Pharmacological testing
if 2.5 % mecholyl or 0.125% pilocarpin is instilled into both eyes , the normal pupil will not constrict , but abnormal pupil will because of denervation hypersensitivity.

Oculosympathetic palsy

Horner syndrome
Clinical feature
Mild ptosis (usu 1-2 mm) as a result of weakness of muller muscle .
Slight elevation of the inferior eyelid as aresult of weakness of inferior tarsal muscle .
Miosis resulting from unopposed action of sphincter pupillae , with resultant anisocoria which accentuated in dim light .since horner pupil will not dilate ,like its fellow .
Normal reaction to light and near
Reduced ipsilateral sweating
Hypochromic heterochromia ( iris of different color horner is lighter ) may be seen in if the lesion congenital or long standing
Pupil is slow to dilate
Less imp sign ocular hypotonic and conjunctival hypermia
Pharmacological test
Cocaine confirm the diagnosis
Hydroxyamphetamine (paredine ) may be used to differentiate a preganglionic from post ganglionic lesion .
Adrenaline may also be used to assess denervation super sensitivity .
Investigation
Chest x-ray
CT scan of chest with specific apex view
CT/ MRI of head and neck
Angiography if carotid dissection is suspected


Causes of anisocoria
Simple anisocoria
Trauma / iris damage
Posterior synchiae
Horner syndrome
Adie s pupil
Third cranial nerve palsy
Topical drug induced
unilateral administration of miotic or mydriatic

Done by Omar Abid ALsamrrae