The pupil is an aperture in the iris that controls the amount of light entering the eye. It is controlled by two opposing muscles - the sphincter pupillae and dilator pupillae. The sphincter pupillae causes constriction under parasympathetic influence while the dilator pupillae causes dilation under sympathetic influence. The normal pupil size is maintained by a balance between these two muscles. Pupils undergo several reflexes including the light reflex, near reflex, and psychosensory reflex. Lesions in the pupillary pathway at different locations can cause specific pupillary reflex abnormalities such as Argyll Robertson pupils or Horner's syndrome.

1. PUPIL
Shruthi.s.jayaraj ,53rd

2. PUPIL
• aperture of the diaphragm of eye (iris) that
allows light to enter the retina
FUNCTION
• Controls amount of light entering the eye –
influence of ANS

3. Not all animals have circular pupil !!

4. • Pupils are controlled by 2 muscles of
ectodermal origin –
1. Sphincter pupillae
2. Dilator pupillae

6. • Circular fibres – parasympathetic supply –
miosis
• Radial fibres – cervical sympathetic nerves –
mydriasis
BALANCE OF TONE BETWEEN THE 2
ANTAGONIST MUSCLES MAINTAIN THE
NORMAL PUPIL SIZE

7. • TONE OF SPHINCTER MUSCLE > TONE OF
RADIAL MUSCLE (keeps the pupil slightly
contracted )
• Pupils are equal normally on both sides
unequal
anisocoria

8. note
1. normally there is one pupil. More than 1 pupil
is called polycoria
2.Pupil location almost central,slightly
nasal..eccentric pupil is called correctopia

9. • Pupil size varies depending on the background
illumination (2-3 mm normally)
• Diameter affects the type of image formed
Note the size,shape & contour
of the pupil.then test for reflexes

10. PUPILLARY REFLEXES
PUPILS PARTICIPATE IN SEVERAL REFLEXES
• LIGHT REFLEXES –
DIRECT,INDIRECT
• NEAR REFLEX
• PSYCHOSENSORY REFLEX

11. Keep in mind!!
• Illumination of examination room should be
low
• Patient should look into the distance
• Light used should be focussed & bright

12. • DIRECT & INDIRECT
When light is shone in one eye,both the pupils
constrict..
Constriction of pupil to which light is shone is
direct light reflex and that of other is
consentual ( indirect ) light reflex.

13. • Using a bright focussed light
• In a dark room
• Finer examination – slit lamp

14. Swinging flashlight test

16. • If both optic nerves are intact, both pupils will
be tightly constricted
(direct’ magnitude = concensual)
If one optic nerve damaged,both pupils dilate
on showing the light to the diseased eye.
on swinging back to normal side,both pupils
constrict

17. • The dilatation or escape that occurs is called
MARCUS GUNN PUPIL or AFFERENT
PUPILLARY DEFECT.

18. NEAR REFLEX
OCCURS ON LOOKING AT A NEAR OBJECT.
IT HAS 2 COMPONENTS :
CONVERGENCE REFLEX
(contraction of pupil on convergence)
ACCOMODATION REFLEX
(constriction of pupil on viewing a near target)

19. Convergence reflex

20. Accomodation
reflex

21. PSYCHOSENSORY REFLEX
Refers to the dilatation of pupil in response to
sensory and psychic stimuli
Complex, mechanism still not elucidated

22. • Light reflexes
• Near reflex
• Psychosensory reflexes
OF PUPIL

23. PUPILLARY PATHWAY
SHORT
CILIARY
NERVES
N.TO INFERIOR
OBLIQUE

24. Pupillary pathway

25. LESIONS IN THE PUPILLARY PATHWAY

26. OPTIC
NERVE

27. 1.OPTIC NERVE
• Abolition of direct reflex on affected side &
consentual on opposite side
amaurotic pupil

28. MEDIAL CHIASMA

29. •
Medial chiasma
bitemporal hemianopic paralysis

30. LATERAL CHIASMA

31. lateral chiasma
binasal hemianopic paralysis

32. OPTIC TRACT

33. •
OPTIC TRACT
CONTRALATERAL HEMIANOPIC PARALYSIS
(WERNICKE PARALYSIS)
NO LIGHT REFLEX WHEN LIGHT IS THROWN ON
TEMPORAL HALF OF RETINA OF AFFECTED SIDE &
NASAL HALF OF OPPOSITE SIDE

34. PROXIMAL PART OF OPTIC TRACT

35. • LESION OF PROXIMAL PART OF OPTIC TRACT –
NORMAL PUPILLARY REACTIONS

36. IN THE REGION OF
BRACHIUM &
TECTUM
CONTRALATERAL
HEMIANOPIC PARALYSIS

37. CENTRAL
DECUSSATION

38. • BILATERAL REFLEX PARALYSIS
• INACTIVITY TO LIGHT REFLEX WITH
RETENTION OF NEAR REFLEX !!
ARGYLL ROBERTSON PUPIL

41. ARGYLL ROBERTSON PUPIL
• Pupil slightly smaller in size
• Near reflex present but Light reflex absent i.e
there is light near dissociation
• Both pupils are involved ,dilate poorly with
mydraiatics
• Hallmark of tertiary syphilis (neurosyphilis)

43. B/W DECUSSATION &
CONSTRICTOR
CENTRE –
UNILATERAL ARP

44. PARTIAL LESION

45. • Ipsilateral abolition of direct reflex,with
retention of indirect
• Retention of both contralaterally

46. NUCLEAR
/EXTENSIVE
SUPRANUCLEAR
LESION
Ipsilateral absolute pupillary
paralysis

47. 3RD NERVE
Ipsilateral absolute pupillary
paralysis

48. CILIARY
GANGLION

49. Lesion at ciliary ganglion
• Light reflex absent,retention of near reflex
(very slow) and tonic
ADIE’S TONIC PUPIL

50. Adie’s pupil
Affected pupil is larger
Usually unilateral
a/w absent knee jerk ( HOLMES ADIE SYN)
young women

51. • adies’s pupil constricts with weak
pilocarpine (.125 %) while normal pupil does
not
denervated iris sphincter is supersensitive to
topical parasympathomimetics

52. OTHER CONDITIONS AFFECTING PUPILS….

53. Ophthalmoplegia interna
• d/t lesion in 3rd nerve nucleus
• paralysis of both sphincter pupillae & ciliary
ms
• Dilated,immobile pupils
• Meningitis,encephalitis,cerebral syphilis,
trauma affecting 3rd nerve and ciliary ganglion
etc

54. Unilateral dilatation may result
from irritation of cervical
symapthetic nerves(swollen lymph
nodes,cervical rib,apical
pneumonia,meningitis affecting lower
cervical &upper thoracic ventral roots..)
IRRITATIVE DILATATION
EVENTUALLY LEAD TO
CONSTRICTION FROM
SYMPATHETIC
PARALYSIS

55. •
•
•
•
When all sympathetic function on one side is
lost,it result in
miosis,
slight enophthalmos
horner syndrome
ptosis
anhydrosis on affected side

56. HORNER’S

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