1. Pupillary pathways & reactions
Dr. C.R.Thirumalachar

2. Pupillary constrictor/ spincter-innervated by parasympathetic
Pupillary dilator – innervated by sympathetic
Evaluation of pupil- Diagnostic clue to ocular, neurological, medical, surgical and paediatric diseases

3. Light reflex: Direct & Consensual – Afferent pathway
Initiated by retinal photoreceptors
Transmitted along optic nerve
Undergo a hemidecussation at the optic chiasma (nasal fibres cross over)
Proceeds along optic tract
Short of lateral geniculate body- enters midbrain via sup. Brachium of sup. Colliculus
Synapses at pre- tectal nucleus
Ends in both Edinger westpal nucleui

4. A second decussation occurs around aqueduct of sylvius
Decussation at chiasma & midbrain level between pretectal nucleus & Edinger Westpal nucleus accounts for consensual light reflex
E.W. nucleus (pupillo motor constrictor centre)
Efferent fibres tract along 3rd nerve-nerve to inf. Obl.
Enter the ciliary ganglion through its short motor root
Synapse & relay at ciliary ganglion
Post ganglionic fibres reach ciliary muscle and iris spincter through short ciliary nerves

5. Light Reflex

6. Near relex Accomodation reflex:
Stimulus : Blurring of retinal images when object is near
Retina- Optic nerve – Optic chiasma- Optic tract- Optic radiations- Lat geniculate body- visual cortex – cortical association areas- occipito mesencephalic tract- mid brain- E.W. nucleus- 3rd nerve- accessory ciliary ganglion along short ciliary nerves- ciliary muscle and pupil constrictor

7. Near reflex- convergence relex
Co contraction of both medial recti
Proprioceptive impulses originate and travel along 5th nerve
Reach mesencephalic root of 5th nerve
Transmitted to EWP nucleus in midbrain via convergence centre (Perlias N)
From EWP efferent pathway same as accomodation reflex

8. Accomodation Reflex

9. Dilator pathway
Hypothalamic dilator centre - part of sympathetic system
Descends through brainstem to the spinal cord
C8- T2 segments of spinal cord cilio spinal centre of Budge

10. Emerge out of spinal cord – enter paravertebral symp chain & synapses sup cervical ganglion
Symp plexus around carotid artery
Enter cranial cavity along internal carotid artery
Trigeminal ganglion – ophthalmic division – nasociliary nerve- long ciliary nerves- ciliary muscle and dilator pupillae

11. Sympathetic Pupillary system

12. Abnormal pupillary reactions
RAPD
RAPD seen in optic nerve & retinal diseases with extensive retinal damage , gross macular lesions.
Accurate quantification of RAPD (using neutral density filters)– is accomplished by determination of the log unit difference needed to balance the pupil reaction between the 2 eyes

13. Marcus Gunn Pupil
-When the contralateral/normal eye is covered, pupil on the affected side dilates
-When the affected eye is covered pupil of the normal eye remains unaffected.
Light is thrown on ipsilateral side(affected side);Ipsilateral direct reflex & contralateral consensual reflex- sluggish and ill sustained.
Light thrown on contralateral side (normal side) direct & consensual (affected side) is normal & well sustained

14. -If light is kept persistently on affected side, pupil may show initial sluggish contraction but contraction is ill sustained & gradually shows paradoxical dilatation
-Indicates conduction defect along efferent pathway (Optic nerve, Optic chiasma, part of optic tract, dorsal mid brain )

15. Argyll Robertson pupil(ARP)
Occurs in neurosyphilis, Tabesdorsalis,G.P.I.
Pupil is usually constricted ( involvement of descending sympathetic dilator fibres)
Light reflex is absent
Accomodation reflex , near reflex retained
Site of lesion –Pretectal nucleus. (dorsal mid brain)

16. Horner’s syndrome : Involvement of cervical sympathetic
Miosis, partial ptosis, enophthalmos & anhydrosis
Iris heterochromia

17. Pourfour de Petit Syndrome
This syndrome is the clinical opposite of Horner syndrome. It represents oculosympathetic overactivity
unilateral mydriasis, lid retraction, apparent exophthalmos, and conjunctival blanching
Seen after trauma, brachial plexus anesthetic block or other injury, and parotidectomy

18. Hemianopic pupil ( wernicke’s pupil )
Seen in optic tract lesions with hemianopia
Stimulating the blind half of retina pupil shows no reaction
Stimulating seeing half of retina pupil shows reaction
Difficult to elicit – due to scattering & diffusion of light
Use a narrow streak of light

19. Hutchinson’s pupil Useful in assessment of head injuries
Stage1 : Ipsilateral pupil (on the side of head injury shows contraction due to irritation, Contralateral (normal) pupil –normal
Stage2 : Ipsilateral pupil shows dilatation due to paralysis , contralateral pupil constricts (irritation spreads to normal side)

20. Stage3 : Both pupils dilate. Stage of bilateral paralysis
Stage3 : Both pupils dilate. Stage of bilateral paralysis. To assess pupil repeatedly is important, therefore mydriatics should be avoided in case of head injuries

21. Adie’s tonic pupil: Characterised by
large unilaterally dilated pupil
Absent / poor light response
In near response , there is slow / tonic contraction of the iris
May be associated with loss of deep tendon reflexes (Adie’s syndrome)
Seen in young women

22. Pupil in 3rd nerve palsy Dilated Non reactive Absolute motor paralysis
Associated with ptosis, deviation of eyeball

23. Pupil in diabetes Constricted Sluggishly reactive due to
Glycogen infiltration of spincter
Autonomic denervation
Arteriosclerosis of radial iris vessels

24. Thank You