Students:
Rahaf Hasanein
Mohammad Jomaa
Heba Abu Khalaf
Nebras abu abed
Reviewed and Modified: Dr Mohammad Abusamak FRCS
Collected by: Rahaf Jereisat
Visual pathway consists of :
Retina / optic nerve / optic chiasm / optic tracts / lateral geniculate
bodies/optic radiations / visual cortex
Control of retinal Illumination.
Reduces optical aberrations.
Depth of focus by miosis (pinhole effect(
In dim light, pupil dilates maximizes the number of photons to
enhance dark adaptation.
A small pupil reduces spherical and chromatic aberration.
After Refractive surgery, patient with large pupil have more
bothersome symptoms (glare at night)
In light adaptation, pupil constricts and enhances light adaptation.
When the eye focus on near object, they converge and the pupils
constrict (the near response)
are controlled by parasympathetic and sympathetic nervous system.
Sympathetic -> mydriasis
Parasympathetic -> miosis
Constriction of pupil
more Light on >> optic nerve crossing >> optic tract>> activate
both pretectal nucleus >>Edinger-Westphal
nucleus>>occulomotor (parasympathatic)>>ciliary ganglion>>
short ciliary nerves
dilation of pupil
Originate in post. hypothalmus >>ciliospinal center (c8-
T2)>>superior cervical ganglion>>trigeminal nerve>> ophthalmic
nerve >>nasociliary N<<LONG ciliary nerve
Anisocoria….. Inequality of pupils sizes.
Drugs.
Trauma.
Sympathetic lesions (Horner’s).
Parasympathetis lesions (Adie’s, Third nerve Palsy).
20% of people may have anisocoria
Measure afferent input. (RAPD)
Indicates awakefulness.
Excited individuals - larger pupil.
Slept , on narcotics - smaller pupil.
Central inhibition (parasympathomimetic) at level of
midbrain.
Autonomic functions.
Pupil diameter and optical aberrations.
Pharmacological response.
1.ocular disease
2.disorders of the controlling neural pathway;
3.pharmacological action
1.Ocular diseases
anterior uveitis due to Ocular synechiae.
intraocular surgery
blunt trauma to the eye, which may rupture the sphincter muscle,
causing irregularity or fixed dilation (traumatic mydriasis)
an acute and severe rise in ocular pressure – as in acute
glaucoma.
2. Neurological Causes
Best detected by swinging light torch:
light is repeatedly shone into the affected eye alternating with the
good side. When the light is shining on the unaffected eye, both
pupils constrict. When it’s transferred to the diseased side, there
is bilateral pupillary dilation. While the near reflex is intact.
A lesion of the optic nerve on one side blocks the afferent limb of
the pupillary light reflex.
Testing for an RAPD is critical in a patient suspected of having an
optic nerve lesion, such as optic neuritis .
An RAPD may be seen in very severe disease of the retina but not
with opacities of the cornea or lens.
**Interruption of the sympathetic pathway manifestations:
Miosis on the affected side.
Dilation Lag (pupil dilates slowly in dark room, anisocria greatest
first 4-5 seconds after light it turned off)
A slight ptosis on the affected side. “up-side down ptosis”
Enophthalmos, The reduced palpebral aperture size gives an
impression of recession.
Anhydrosis on the affected side, if the sympathetic pathway is
affected proximal to the base of the skull.
conjunctival injection
**Due to its extended pathway, The sympathetic pathway may be
affected by a multitude of pathologies Examples include:
Syringomyelia , an expanding cavity within the spinal cord,
sometimes extending into the medulla (syringobulbia), which
compresses the pathway. Typically, it also causes wasting of the
hand muscles and loss of sensation.
Small - cell carcinoma at the lung apex which catches the cervical
sympathetic chain. Involvement of the brachial plexus gives rise to
pain and to T1 wasting of the small muscles of the hand in
Pancoast’s syndrome.
Neck injury, disease or surgery .
Cavernous sinus disease – catching the sympathetic carotid plexus
in the sinus.
Right Horner’s Syndrome before and after Cocaine
test
Diagnosis of Horner’s
Cocaine (prevents reuptake of Norepinephrine) , 4% or 10%.
After application by 40-60 minutes , check pupils.
Presence of >=1 mm aniosorocia after cocoaine is positive test.
Hydro
xyamphetamine (differentiates pre- from post-ganglionic lesions).
Apraclonidine (reversal of anisocoria , alpha-1 supersensitivity)
1. Adie’s tonic pupil
2. The Argyll Robertson pupil
3. peri- aqueductal brainstem lesions such as Parinaud’s syndrome .
4. Other causes include diabetes, multiple sclerosis, severe optic
nerve disease and midbrain lesions.
1.Adie's Tonic Pupil
neurological disorder that causes one or both pupils to be abnormally
dilated (mydriasis) with delayed constriction in response to exposure to
light but better response to accomodation(chronic stage(
Heterochromia
Horner ’s syndrome may also be congenital, in which case the iris colour may be altered when compared to the fellow eye (heterochromia).
Due to ciliary ganglionitis which denervates the parasympathetic
supply to the iris and ciliary body (immune mediated)
Women, youngs and it’s benign.
Segmental denervation (sectoral palsy(
50% bilateral in 10 years.
The consequences are
Unilateral enlarged pupil that can become bilateral overtime.
Poor reaction to light with characteristic slow , worm-
like(vermiform) contraction of iris .(sectoral paresis)
Slow sustained miosis on accommodation (hence the name tonic),
results from muscarinic supersenitivity.
Constricts to dilute pilocarpine (0.1%), unlike the normal pupil.
Can be part of bigger syndrome: adie-holmes syndrome, Areflexia
The ciliary body is nine times more innervated than iris so it isn’t
affected as the iris.
Cholinergic Supersensitivity
0.125% Pilocarpine produces more constriction in the abnormal
pupil.
Develops in 5-7 days.
Can occur in CN III palsy as well
2.Argyll Robertson pupil
The pupils are bilaterally small and irregular. They do not react to light
but respond to accommodation
Seen in neurosyphilis, it’s suggested that a periaqueductal lesion on
dorsal aspect of edinger-westphal nucleus involves fibres associated
with response to light but spares those associated with near response .
3.Parinaud's syndrome
1. Pupils not reactive to light
2. Limited in elevation (upgaze palsy)
3. Convergence – retraction nystagmus
coma, both pupils may become miosed with preservation of the
light reflex if a pontine lesion is present.
Coma associated with a unilateral expanding supratentorial mass,
e.g. haematoma, results in pressure on the third nerve and
dilation of the pupil .
Midbrain lesions cause loss of the light reflex with mid-point
pupils
Intrinsic third nerve (Parasympathatic) lesions also cause a dilated
pupil.
Midbrain pupil:
Arises from lesions affecting the pretectal nuclear complex in dorsal
region of midbrain produces mydriasis and light near dissociation .
Causes include demyelination, infarction, enlargement of 3rd ventricle
and space occupying tumors such as pineloma .
3. Pharmacological Agents
1. Pathological miosis is seen in
a. Horner’s syndrome.
b. Third nerve palsy.
c. Argyll Robertson pupil.
d. Coma.
e. Systemic and topical atropine treatment.
2. Horner ’ s syndrome may be seen in
a. Syringomyelia.
b. Lung neoplasia.
c. Cavernous sinus disease.
d. Myasthenia gravis.
e. Carotid artery dissection.
3. Light – near dissociation
a. The reaction of the pupils is greater to light than accommodation.
b. May be seen in diabetes.
c. Is seen in Horner’s syndrome.
d. Is seen in patients with an Argyll Robertson pupil.
e. Is seen following administration of tropicamide drops.
4. Match the drop to its action: dilates (mydriasis) or constricts (miosis.)
a. Cyclopentolate.
b. Atropine.
c. Pilocarpine. (constricts)
d. Tropicamide.
e. Phenylephrine.
Differential diagnosis: pupil
Choose the most appropriate single diagnosis in the following abnormalities affecting the
pupils.
1. A 25 - year - old female comes into the surgery concerned that in a recent group
photograph it was pointed out to her that the right pupil looked bigger than the left.
She had no visual problems and no diplopia. On examination her eye movements
were full, no ptosis was present and the difference in pupil size was confirmed. The
right pupil constricted poorly to light.
=The poorly reacting pupil is the key to the diagnosis; on a slit - lamp examination
vermiform movements would be observed. Absent reflexes would help to confirm
the diagnosis.
2. A 67 - year - old man who had smoked all his life noted that his left pupil was smaller
than his right and his left lid drooped slightly. On examination the findings were
confirmed and both pupils reacted normally to light. The difference in pupil size was
more pronounced in the dark.
=Horner’s syndrome. The history of smoking makes the investigation for associated
chest neoplasia important.
3. An 80 - year - old man with a diagnosis of glaucoma for which he had been on the
same treatment for many years attended his optician. He was noted to have
bilaterally small pupils which did not appear to react to light.
=It is likely that he is taking pilocarpine to treat his glaucoma. This is an unusual drop
to prescribe to treat the condition today but was a mainstay of treatment in the
past.
4. A 45 - year - old man attended his GP with a frontal headache and reduced vision in
his left eye. The GP confirmed that the vision was reduced and noted that although
the pupils were equal, when a light was moved from the right to the left eye both
pupils appeared to dilate. The optic nerve on the left appeared pale, that on the
right was normal .
=This is a relative afferent pupillary defect. The pallor of the optic disc confirms the
likelihood of optic nerve disease.
5. A child suspected of having a squint had been taken to the eye hospital one
afternoon. The following morning his mother phoned the GP saying that his pupils
were dilated.
=Cyclopentolate drops are applied to dilate the pupil and allow an examination of
the fundus. The effect of the drops may last for some hours.
Differential diagnosis: field defect
Choose the most appropriate single field defect in the following situations
1. A 77 - year - old man with hypertension and diabetes notices that he is unable to see
on the left hand side. An MRI scan confirms a right cortical infarct.
=A posteriorly placed visual pathway lesion causes a congruous defect (similar
defect in both eyes); those affecting the optic tract are incongruous.
2. A 50 - year - old man presents to his GP saying that he feels his peripheral vision is
reduced and he often spilled the water when making a cup of tea. The GP notes that
although his acuity was normal he missed the temporal letters on the Snellen chart
with each eye.
=The symptoms suggest the possibility of a bitemporal hemianopia and the patient’s
performance on the Snellen chart helps to confirm the presence of this type of field
defect arising from a chiasmal lesion.
3. A 62 - year - old lady was found by her optometrist to have a raised intraocular
pressure in the right eye. He noted that the optic disc appeared cupped on the right
compared to the left. The eye otherwise appeared normal.
=An arcuate fi eld defect is typical of glaucoma.