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PUPIL AND PUPILLARY PATHWAY.pptx
- 1. THE PUPIL AND PUPILLARYPATHWAY PRESENTER- DR SREYA CHAKRABORTY GUIDE – DR S.PANDA
- 2. PUPIL AN APERTURELOCATED IN THE CENTRE OF IRIS THAT ALLOWS LIGHT TO ENTER THE RETINA . NUMBER- NORMALLY ONE PUPIL IN EACH EYE LOCATION- NORMAL PUPIL IS PLACED ALMOST IN THE CENTRE (SLIGHTLY NASAL) OF THE IRIS. SHAPE – CIRCULAR COLOUR- GREYISH BLACK SIZE- NORMAL PUPILS RANGE FROM 3 TO 5 mm IN AMBIENT LIGHT CONDITIONS.
- 3. FUNCTIONS OF PUPIL LIMITS THE AMOUNT OF LIGHT ENTERING THE EYE. HELPS IN LIGHT AND DARK ADAPTATIONS CONTROLS AMOUNT OF CHROMATIC AND SPHERICAL ABERRATIONS A PHARMACOLOGICAL INDICATOR
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- 5. PUPILLARY REFLEXES LIGHT REFLEX NEARREFLEX DARKNESS REFLEX PSYCHOSENSORY REFLEX
- 6. LIGHT REFLEX WHENLIGHT IS SHONE IN ONE EYE BOTH THE PUPILS CONSTRICT DIRECT LIGHT REFLEX- CONSTRICTION OF THE PUPIL TO WHICH LIGHT IS SHONE INDIRECT( CONSENSUAL) LIGHT REFLEX- CONSTRICTION OF THE OTHER PUPIL IN NORMAL SUBJECTS, DIRECT LIGHT REFLEX EQUALS CONSENSUAL WITH RESPECT TO TIME, COURSE AND MAGNITUDE. RESPONSE SUMMATES IF BOTH PUPILS ARE ILLUMINATED SIMULTANEOUSLY.
- 7. PATHWAY OF LIGHTREFLEX THE AFFERENT FIBRES EXTEND FROM RETINA TO THE PRETECTAL NUCLEUS IN THE MIDBRAIN INTERNUNCIAL FIBRES CONNECT EACH PRETECTAL NUCLEUS WITH EDINGER WESTPHAL NUCLEUS OF BOTH SIDES THE EFFERENT PATHWAY CONSISTS OF PARASYMPATHETIC FIBRES FROM EDINGER WESTPHAL NUCLEUS VIA THIRD NERVE TO CILIARY GANGLION AND SPHINCTER PUPILLAE
- 8. AFFERENT PATHWAY RODS ANDCONES GANGLION CELLS OPTIC NERVE OPTIC CHIASMA OPTIC TRACT
- 9. AFFERENT PATHWAY(CONTD..) NASALFIBRES OF THE OPTIC NERVE DECUSSATE IN THE OPTIC CHAISMA TRAVEL TO CONTRALATERAL OPTIC TRACT TO CONTRALATERAL PRE TECTAL NUCLEUS FIBRES FROM TEMPORAL RETINA REMAINS UNCROSSED AND TRAVELS ALONG IPSILATERAL OPTIC TRACT TO END IN IPSILATERAL PRETECTAL NUCLEUS HALF OF THE POSTSYNAPTIC FIBRES CURVE AROUND PERIAQUEDUCTAL GREY MATTER TO TERMINATE IN I/L EW NUCLEUS ,OTHER HALF CROSS VIA POST COMMISSURE TO TERMINATE IN CONTRALATERAL EW NUCLEUS
- 10. EFFERENT PATHWAY THEPREGANGLIONIC FIBRES ENTER THE INFERIOR DIVISION OF THIRD NERVE VIA NERVE TO INFERIOR OBLIQUE AND REACH CILIARY GANGLION TO RELAY POST GANGLIONIC FIBRES LEAVES THE CILIARY GANGLION AND TRAVEL ALONG SHORT CILIARY NERVES TO INNERVATE THE SPHINCTER PUPILLAE.
- 11. PREREQUISITES FOR ELICITINGDIRECT AND INDIRECT LIGHT REFLEX SEMIDARKENED ROOM A GOOD UNIFORM LIGHT SOURCE – A PEN TORCH ASK THE PATIENT TO LOOK AT A DISTANT OBJECT THE DIRECTION OF ILLUMINATION SHOULD BE FROM BELOW AND SLIGHTLY TEMPORAL. SWING BRIGHT LIGHT SOURCE IN A QUICK MOTION ON TO THE EYE.
- 12. CONSENSUAL LIGHT REFLEX KEEP ROOM AS DIM AS POSSIBLE ASK THE PATIENT TO LOOK AT DISTANT TARGET EXAMINER’S HAND OR CARDBOARD IS PLACED IN BETWEEN TWO EYES LIGHT IS SHONE IN ONE EYE AND RESPONSE IS NOTED IN OTHER EYE NORMALLY THE OTHER PUPIL CONSTRICTS
- 13. FUNCTIONS OF LIGHTREFLEX PUPILLARY CONSTRICTION ASSOCIATED WITH LIGHT REFLEX PROTECTS AGAINST EXCESSIVE BLEACHING OF VISUAL PIGMENTS BY REDUCING AMOUNT OF LIGHT ENTERING THE EYE. HELPS IN LIGHT AND DARK ADAPTATION.
- 14. ABSENT LIGHT REFLEX USE OF MYDRIATICS AND CYCLOPLEGIC INTERNAL OPHTHALMOPLEGIA BRAINSTEM LESIONS AT THE LEVEL OF SUPERIOR COLLICULUS AND RED NUCLEUS LESIONS OF CILIARY GANGLION OR SHORT CILIARY NERVES IRIS DAMAGE SECONDARY TO PREVIOUS SURGERY FASCICULAR THIRD NERVE LESIONS SEVERE OPTIC NEURITIS , TOTAL OPTIC ATROPHY,CRAO, TRANSECTION OF OPTIC NERVE.
- 15. NEAR REFLEX THENEAR REFLEX IS ACTIVATED WHEN GAZE IS CHANGED FROM A DISTANT TO A NEAR TARGET. TWO COMPONENTS 1.CONVERGENCE REFLEX – CONTRACTION OF PUPIL ON CONVERGENCE 2.ACCOMODATION REFLEX- CONTRACTION OF PUPIL ASSOCIATED WITH ACCOMODATION. VISION IS NOT A PREREQUISITE . THERE IS NO CLINICAL CONDITION IN WHICH THE LIGHT REFLEX IS PRESENT BUT THE NEAR RESPONSE ABSENT.
- 16. PATHWAY OF CONVERGENCEREFLEX AFFERENT PATHWAY FROM MEDIAL RECTI VIA 3RD NERVE TO MESENCEPHALIC NUCLEUS OF 5TH NERVE TO A PRESUMPTIVE CONVERGENCE CENTRE IN PRETECTAL OR TECTAL REGION INTERNUNCIAL FIBRES FROM CONVERGENCE CENTRE TO EDINGER WESTPHAL NUCLEUS EFFERENT PATHWAY FROM EW NUCLEUS ALONG THIRD NERVE TO SPHINCTER PUPILLAE
- 17. PATHWAY OF ACCOMODATIONREFLEX AFFERENT PATHWAY FROM RETINA TO PARASTRIATE CORTEX INTERNUNCIAL PATHWAY FROM PARASTRIATE CORTEX TO EW NUCLEUS VIA OCCIPITOMESENCEPHALIC TRACT AND PONTINE CENTRE EFFERENT PATHWAY FROM EW NUCLEUS VIA 3RD NERVE REACH SPHINCTER PIPILLAE AND CILIARY MUSCLE
- 18. METHOD INSTRUCT THEPATIENT TO LOOK AT THE DISTANT TARGET. THE EXAMINER HOLDS UP A TARGET APPROXIMATELY 25 cm FROM THE PATIENT ASK THE PATIENT TO FIXATE THE NEAR TARGET AND LOOK FOR PUPIL CONTRACTION NOTE THE SPEED OF THE CONSTRICTION AND ROUNDNESS OF EACH PUPIL
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- 20. CAUSES FOR DILATATION 1. SIMPLY ABOLITION OF LIGHT REFLEX WITH CONSEQUENT RELAXATION OF SPHINCTER PUPILLAE 2. CONTRACTION OF DILATOR PUPILLAE SUPPLIED BY SYMPATHETIC NERVOUS SYSTEM
- 21. PSYCHOSENSORY REFLEXES ITREFERS TO DILATATION OF PUPIL IN RESPONSE TO SENSORY AND PSYCHIC STIMULI. THE PSYCHOSENSORY REFLEXES ARE NOT SEEN IN NEWBORN > APPEAR IN FIRST FEW DAYS OF LIFE > DEVELOPING FULLY BY THE AGE OF 6 MONTHS MECHANISM OF PSYCHOSENSORY REFLEXES IS A CORTICAL ONE AND PUPIL DILATATION OCCURS DUE TO TWO FACTORS 1. SYMPATHETIC DISCHARGE TO THE DILATOR PUPILLAE 2.INHIBITION OF PARASYMPATHETIC DISCHARGE TO THE SPHINCTER PUPILLAE
- 22. LID CLOSURE REFLEX CONSTRICTION OF PUPIL ASSOCIATED WITH BLINKING HOMOLATERAL PUPILLARY CONSTRICTION ASSOCIATED WITH CLOSURE OF EYELID PUPILLARY CONSTRICTION ASSOCIATED WITH LID CLOSURE ON TOUCHING THE CORNEA( OCULOPUPILLARY REFLEX)
- 23. ABNORMALITIES OF PUPILLARYREFLEXES AFFERENT PUPILLARY DEFECTS 1.TAPD 2.RAPD OR MARCUS GUNN PUPIL 3.WERNICKE’S HEMIANOPIC PUPIL
- 24. TOTAL AFFERENT PATHWAY DEFECT(TAPD) CAUSED BY COMPLETE OPTIC NERVE LESION OR RETINAL LESION LEADING TO TOTAL BLINDNESS ON THE AFFECTED SIDE. CHARACTERIZED BY ABSENCE OF DIRECT LIGHT REFLEX ON THE AFFECTED SIDE AND ABSENCE OF CONSENSUAL LIGHT REFLEX ON NORMAL SIDE WHEN THE NORMAL EYE IS STIMULATED BOTH PUPILS REACT NORMALLY NEAR REFLEX IS NORMAL IN BOTH EYES. IN DIFFUSE ILLUMINATION, BOTH PUPILS ARE EQUAL IN SIZE
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- 26. RELATIVE AFFERENT PATHWAYDEFECT IT IS PARADOXICAL RESPONSE OF PUPIL TO LIGHT. IT IS TESTED BY “SWINGING FLASHLIGHT TEST” . IT IS CAUSED BY INCOMPLETE OPTIC NERVE LESION OR A SEVERE RETINAL DISEASE.
- 27. CAUSES OF RAPD OPTIC NEURITIS ANTERIOR ISCHAEMIC OPTIC NEUROPATHY COMPRESSIVE OPTIC NEUROPATHY OPTIC NERVE TUMOURS ISCHAEMIC RETINAL DISEASES : CRAO,CRVO,BRAO,BRVO RETINAL DETACHMENT CHIASMAL COMPRESSION OPTIC TRACT LESION
- 28. SWINGING FLASHLIGHT TEST KEEP ROOM AS DIM AS POSSIBLE THE TEST REQUIRES NORMAL EFFERENT PATHWAY AND PUPILLARY SPHINCTER ON ATLEAST ONE SIDE ASK THE PT TO LOOK AT DISTANT TARGET . BOTH PUPILS ARE EQUALLY DILATED IN DIM LIGHT SWING BRIGHT LIGHT SOURCE IN QUICK MOTION ON TO THE EYE AND OBSERVE REACTION OF THE PUPIL. AFTER ABOUT 3 SECS,RAPIDLY SWING THE LIGHT SOURCE TO THE OPPOSITE PUPIL AND OBSERVE ITS REACTION NORMALLY BOTH PUPILS CONSTRICT EQUALLY IN THE PRESENCE OF RAPD IN ONE EYE, THE AFFECTED PUPIL WILL DILATE WHEN FLASHLIGHT IS MOVED FROM THE NORMAL EYE TO THE ABNORMAL EYE THIS RESPONSE IS CALLED MARCUS GUNN PUPIL. IT IS THE EARLIEST INDICATOR OF OPTIC NERVE DISEASE EVEN IN THE PRESENCE OF NORMAL VISUAL ACUITY.
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- 30. GRADING SCALE OFRAPD GRADE1 – WEAK INITIAL CONSTRICTION FOLLOWED BY GREATER REDILATATION GRADE 2 – AN INITIAL STALL FOLLOWED BY GREATER REDILATATION GRADE 3 – IMMEDIATE PUPIL DILATATION GRADE 4 - – IMMEDIATE PUPIL DILATATION FOLLOWING PROLONGED ILLUMINATION OF THE GOOD EYE FOR 6 SECS GRADE 5 – IMMEDIATE PUPIL DILATATION WITH NO SECONDARY CONSTRICTION
- 31. WERNICKE’S HEMIANOPIC PUPIL CAUSED BY LESION IN THE OPTIC TRACT LIGHT REFLEX ( BOTH I/L AND CONSENSUAL) IS ABSENT WHEN LIGHT IS SHONE TO THE TEMPORAL HALF OF RETINA OF THE AFFECTED SIDE AND NASAL HALF OF RETINA OF OPPOSITE SIDE
- 32. EFFERENT PATHWAY DEFECTS CHARACTERIZED BY ABSENCE OF BOTH DIRECT AND CONSENSUAL LIGHT REFLEX ON THE AFFECTED SIDE AND PRESENCE OF BOTH DIRECT AND CONSENSUAL LIGHT REFLEX ON THE NORMAL SIDE. ON THE AFFECTED SIDE NEAR REFLEX IS ALSO ABSENT PUPIL REMAIN DILATED AND FIXED ON AFFECTED SIDE
- 33. CAUSES BRAINSTEM LESIONS IRIS SPHINCTER DAMAGE TONIC PUPIL THIRD NERVE PALSY TRAUMATIC IRITIS,UVEITIS,ANGLE CLOSURE GLAUCOMA,PSEUDOEXFOLIATION SYNDROME PHARMACOLOGIC AGENTS - MYDRIATICS
- 34. TONIC PUPIL DAMAGETO CILIARY GANGLION OR SHORT CILIARY NERVES FEATURES 1. LIGHT REFLEX IS ABSENT 2.NEAR REFLEX IS SLOW AND TONIC ON AFFECTED SIDE AFFECTED PUPIL IS TONICALLY DILATED AND FIXED ACCOMODATIVE PARESIS CHOLINERGIC HYPERSENSITIVITY OF DENERVATED MUSCLE( CONSTRICTS TO 0.125% PILOCARPINE)
- 35. CAUSES VIRAL CILIARYGANGLIONITIS ORBITAL OR CHOROIDAL TRAUMA OR TUMOURS BLUNT TRAUMA TO GLOBE IDIOPATHIC TONIC PUPIL PERIPHERAL NEUROPATHIES : DIABETES MELLITUS, ALCOHOLISM
- 36. ADIE’S TONIC PUPIL CAUSED BY DENERVATION OF THE POSTGANGLIONIC SUPPLY OF SPHINCTER PUPILLAE AND CILIARY MUSCLE OF UNKNOWN ETIOLOGY USUALLY UNILATERAL TYPICALLY AFFECTS HEALTHY YOUNG WOMEN MORE OFTEN THAN MEN MAYBE ASSOCIATED WITH ABSENT KNEE JERK AFFECTED PUPIL IS LARGE AND IRREGULAR LIGHT REFLEX IS ABSENT OR SLOW NEAR REFLEX IS SLOW AND TONIC ACCOMODATIVE PARESIS
- 37. OCCULOMOTOR NERVE PALSY PUPIL MID DILATED LIGHT,CONSENSUAL ,NEAR REFLEX AFFECTED. PILOCARPINE TEST – NO CONSTRICTION WITH 0.125% PILOCARPINE CONSTRICTION WITH 1%
- 38. PHARMACOLOGIC MYDRIASIS PUPIL WIDELYDILATED (10-12 mm) DILATATION WITH ADRENERGICS BLANCHED CONJUNCTIVAL VESSELS RESIDUAL LIGHT REACTION NO CONSTRICTION WITH 0.125% OR 1% PILOCARPINE
- 39. PUPILLARY LIGHT NEARDISSOCIATION REFERS TO A CONDITION WHERE THE LIGHT REACTION IS ABSENT AND PUPILLARY NEAR REACTION IS PRESENT CAUSES 1. BILATERAL COMPLETE AFFERENT PATHWAY DEFECT 2. ARGYLL ROBERTSON PUPILS 3. DIABETES MELLITUS,ALCOHOLISM, AMYLOIDOSIS 4. PITUITARY TUMOURS 5. PINEALOMAS 6.MYOTONIC DYSTROPHY
- 40. ARGYLL ROBERTSON PUPILS LOCALIZATION- LESION IN TECTUM INTERFERES WITH LIGHT REFLEX FIBRES AND SUPRANUCLEAR INHIBITORY FIBRES BUT DOES NOT AFFECT NEAR REFLEX FIBRES. IT IS USUALLY BILATERAL AND ASYMMETRIC. RETINA SENSITIVE TO LIGHT(GOOD VISION IS PRESENT) PUPIL SMALL AND IRREGULAR. THE LIGHT REFLEX IS ABSENT, BUT THE NEAR REFLEX IS PRESENT SEEN IN TERTIARY SYPHILIS
- 41. HORNER’S SYNDROME PTOSIS-PARALYSIS OF MULLER MUSCLE OF UPPER EYELID MIOSIS – UNOPPOSED ACTION OF SPHINCTER PUPILLAE FOLLOWING PARALYSIS OF DILATOR PUPILLAE PUPILLARY REACTIONS ARE NORMAL TO LIGHT AND NEAR DILATATION LAG – ANISOCORIA INCREASED IN DIM LIGHT FACIAL ANHYDROSIS- REDUCED SWEATING ON THE IPSILATERAL FACE AND NECK. CHARACTERISTIC OF PREGANGLIONIC HORNER’S. HETEROCHROMIA IRIDES – WHEN THE SYMPATHETIC OCULAR INNERVATION IS INTERRUPTED EARLY IN LIFE,THE PIGMENT OF IRIS STROMA FAILS TO DEVELOP OTHER SIGNS INCLUDE OCULAR HYPOTONY IN THE ACUTE PHASE.
- 42. OPHTHALMOLOGICAL CAUSES OF HORNER’SSYNDROME CENTRAL RETINAL ARTERY OCCLUSION CENTRAL RETINAL VEIN OCCLUSION OPTIC ATROPHY MARKED RETINAL DETACHMENT ANTERIOR ISCHAEMIC OPTIC NEUROPATHY BRANCH RETINAL VEIN OCCLUSION ASYMMETRIC PRIMARY OPEN ANGLE GLAUCOMA
- 43. PHARMACOLOGICAL TESTS RATIONALE-COCAINE BLOCKS NE UPTAKE AT POSTGANGLIONIC SYMPATHETIC NERVE ENDINGS RESULT – NORMAL PUPIL WILL DILATE BUT HORNER’S PUPIL WILL NOT BECAUSE IN HORNER’S SYNDROME THERE IS NO NE BEING SECRETED THEREFORE A POST COCAINE ANISOCORIA OF >0.8 mm IN A DIMLY LIT ROOM IS SIGNIFICANT
- 44. HYDROXYAMPHETAMINE 1% RATIONALE– HYDROXYAMPHETAMINE POTENTIATES THE RELEASE OF NE FROM POST GANGLIONIC NERVE ENDINGS RESULT – IN THE PREGANGLIONIC LESION BOTH PUPILS WILL DILATE IN POSTGANGLIONIC LESION – HORNER’S PUPIL WILL CONTINUE TO CONSTRICT
- 45. ADRENALINE AND APRACLONIDINE 1.ADRENALINE 0.1% RATIONALE : THE PRINCIPLE IS BASED ON DENERVATION HYPERSENSITIVITY TO ADRENERGIC NEUROTRANSMITTERS. RESULT : IN PREGANGLIONIC LESION , NEITHER PUPIL WILL DILATE BECAUSE ADRENALINE IS RAPIDLY DESTROYED BY MAO IN POSTGANGLIONIC LESION, HORNER’S SYNDROME WILL DILATE AND PTOSIS WILL BE RELIEVED BECAUSE ADRENALINE IS NOT BROKEN DOWN DUE TO ABSENCE OF MAO. 2. APRACLONIDINE 0.5% OR 1%: RATIONALE : a1 RECEPTORS ARE UPREGULATED IN THE DENERVATED DILATOR PUPILLAE. RESULT : HORNER PUPIL WILL DILATE BUT THE NORMAL PUPIL IS UNAFFECTED.
- 46. TAKE HOME MESSAGE STATE OF PUPIL AND PUPILLARY REACTIONS SERVE AS AN IMPORTANT DIAGNOSTIC CLUE IN DETECTING UNDERLYING PATHOLOGICAL CONDITIONS HELPS IN IDENTIFYING TYPE OF POISONING CAN ALSO ACT AS A PHARMACOLOGICAL INDICATOR MARCUS GUNN PUPIL ACT AS AN EARLIEST INDICATOR OF OPTIC NERVE LESION EVEN IN THE PRESENCE OF GOOD VISUAL ACUITY SO GOOD HISTORY AND PROPER ASSESSMENT OF PUPILLARY REACTIONS SHOULD BE DONE TO EXCLUDE OCULAR CAUSE OF PUPILLARY CHANGES AND TO DIAGNOSE UNDERLYING MEDICAL CONDITIONS.
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