Clinical testing pupils

1. Clinical Testing: Pupils
Dr.Roopchand.PS
Senior Resident Academic
Department of Neurology

2. Introduction:
• The normal pupil size in adults varies from 2
to 4 mm in diameter in bright light to 4 to 8
mm in the dark.
• They constrict to direct illumination (direct
response) and to illumination of the opposite
eye (consensual response).
• The pupil dilates in the dark.
• Both pupils constrict when the eye is focused
on a near object (accommodative response)

3. • The size of the pupil is controlled by
– the circumferential sphincter muscle found in the
margin of the iris
• innervated by the parasympathetic nervous system
– iris dilator muscle, running radially from the iris
root to the peripheral border of the sphincter.
• iris dilator fibers contain α-adrenergic sympathetic
receptors
• Function : control the amount of light entering
eyes for optimal vision.
• Hippus: constant small amplitude fluctuation
of pupil under constant illumination.

4. Retina
Optic tract
Pretectal
nucleus
Edinger–Westphal
nucleus
oculomotor
nerve
ciliary ganglion
Ciliary muscles and
constrictor pupil

6. Observe for:
• SIZE:
– Pupil gauge or millimeter ruler.
– Size < 2mm: miotic
– Size > 6mm : dilated
• SHAPE:
– Round, smooth, regular outline.
• EQUALITY:
– Difference of 0.25mm: noticeable, >2mm
significant.
– 15-20% have physiological anisocoria.
• POSITION:
– Corectopia: eccentric pupils.

8. Pupillary Reflexes:
• Light Reflex
– Constriction of pupils in response to light.
• Accomodation Refelx

9. The Light Reflex:
• Tested in each eye individually
• Patient fixing at a distance
• Light shown to the eye obliquely.
• Cover uncover thechique
– Uses ambient light
• Normal response: brisk constriction -> slight
dilatation back to an intermediate state.

10. • Can be recorded : prompt, sluggish, absent
– Graded 0 to 4+
• THE ACCOMMODATION REFLEX:
– Relax accommodation by gazing a distant object
– Shifting gaze to some near object.
– The primary stimulus for accommodation is
blurring.
– Response: accommodation, convergence, miosis

11. Other reflexes:
• Ciliospinal reflex: dilation of pupil on pain ful
stimulation of ipsilateral neck.
• Occulosensory or occulopupillary reflex:
constriction or dilation followed by
constriction on painful stimuli to eye or its
adnexa.
• Plitz – Westphal reaction.
• Cochleo pupillary reflex & vestibulopupillary
reflex.
• Psychic reflex.

12. Large pupils:
• 3rd nerve palsy.
– With pupil sparing
– With predominant pupil involvement.
– Mid dilated unreactive pupil.
• Adie’s pupil.
– Slow response to light and removal of illumination
– Lesion at ciliary ganglion/ short ciliary nerves
– Denervation supersensitivity.
– Old adie’s pupil: unilateral miosis.

13. • Tectal pupils: large pupils with light near
dissociation.
– seen in lesions affecting the upper midbrain.
• The variably dilated, fixed pupils reflecting
midbrain dysfunction in a comatose patient
carry a bleak prognosis.
• Acute angle closure glaucoma: dilated poorly
reacting pupils
– Cloudy cornea.

14. Small Pupils:
• Pilocarpine eye drops, opiate
• Horner's syndrome.
• Neurosyphilis.

15. Horner's syndrome:
• Ptosis
– Denervation of mullers muscles
• Miosis
– Denervation of dilators
• Anhydrosis
– Sympathetic denervation
• Apparent enophthalmosis
– Narrowing of palpebral fissure
• Absent ciliospinal reflex.

16. • Causes:
– Brain stem lesions
• Lat. Medulla
– Cluster headache
– IC thrombosis/ dissection
– Cavernous sinus disease
– Apical lung tumour
– Neck trauma
– Syringomyelia

17. • Porfour du petit: reverse hornor’s
– Unilateral mydriasis
– Facial flushing
– Hyperhydrosis
– Transient sympathetic over activity
– Early lesions involving sympathetic pathway to
one eye.

18. Localizing lesion:

19. Pharmacologic Testing:
• Cocaine
• Hydroxyam
phetamine
First order
• No
response
• Dilates
Second order
• No
response
• dilates
Third order
• No
response
• No
response

20. Argyll Robertson Pupil:
• Small irregular pupil having light near.
dissociation.
• React poorly to light.
• Normal near response.
• Neurosyphilis.
• Lesion in periaqueductal region, pre tectal,
rostral midbrain

21. Abnormal Reaction:
• Disease of the retina does not affect pupil
reactivity.
• Cataracts and other diseases of the anterior
segment do not impair light transmission.
• Because of the extensive side-to-side crossing
of pupillary control axons through the
posterior commissure, light constricts not only
the pupil stimulated (the direct response) but
also its fellow (the consensual response).

23. Afferent Pupillary Defect:
• The status of the light reflex must be judged
by comparing the two eyes.
• Indicator of optic nerve function
• Swinging flashlight test: light is held about 1 in
from the eye and just below the visual axis;
the light is rapidly alternated.
– The examiner attends only to the stimulated eye.
– Comparing the amplitude and velocity of the
initial constriction in the two eyes

24. • The reaction is relatively weaker when the bad
eye is illuminated.
• The brain detects a relative diminution in light
intensity and the pupil may dilate a bit in
response.
• Bring out the dynamic anisocoria.
• The weaker direct response or the paradoxical
dilation of the light-stimulated pupil is termed
an afferent pupillary defect (APD), or Marcus
Gunn pupil

25. Grading of an Afferent Pupillary
Defect:
• Trace APD: pupil that has an initial
constriction, but then it escapes to a larger
intermediate position than in the other eye.
• 1 to 2+ APD: no change in pupil size initially,
then dilation.
• 3 to 4+ APD: immediate dilation of the
affected pupil.
• Placing neutral density filters over the good
eye

26. • Paradoxical pupils: constrict in darkness
– congenital retinal and optic nerve disorders.
• Springing pupil: intermittent, sometimes alternating,
dilation of one pupil lasting minutes to hours seen in
young, healthy women, often followed by headache.
• Tadpole pupil: pupil intermittently and briefly
becomes comma-shaped because of spasm involving
one sector of the pupillodilator
• Scalloped pupils: occur in familial amyloidosis
• Corectopia iridis: spontaneous, cyclic displacement of
the pupil from the center of the iris.
– seen in severe midbrain disease.