pupillary_pathway_and_abnormalities_82slides.pptx

brief about pupillary embryology, anatomy, reflexes, and abonrmalities

1. Pupillary Pathway & Abnormalities Prepared by: Priyank Rao (custom PPT) Topic: Anatomy, reflexes, tests, and clinical abnormalities

2. Learning Objectives Understand afferent and efferent pupillary pathways Recognize common pupillary abnormalities and their localization Learn clinical tests and pharmacologic challenges

3. Pupil: Basic Anatomy Central aperture in the iris controlling light entry Diameter controlled by sphincter (constrictor) and dilator muscles Embedded within the iris stroma

4. Sphincter Pupillae (Constriction) Circular muscle under parasympathetic control Receives input from Edinger–Westphal → ciliary ganglion Responsible for miosis and light response

5. Dilator Pupillae (Dilation) Radial muscle under sympathetic control Innervated via superior cervical ganglion postganglionic fibers Responsible for mydriasis

6. Autonomic Balance Parasympathetic (CN III) → constriction Sympathetic (hypothalamus → ciliospinal center → SCG) → dilation Pupil size reflects balance between both systems

7. Afferent Limb Overview Light detected by retinal photoreceptors → retinal ganglion cells Signal travels via optic nerve → chiasm → optic tract Fibers to pretectal nuclei mediate pupillary response

8. Retina to Pretectal Nuclei Pretectal nuclei located in dorsal midbrain Each retina sends bilateral input to both pretectal nuclei This enables bilateral pupillary constriction (consensual reflex)

9. Pretectal to Edinger–Westphal Pretectal nuclei project to both Edinger–Westphal nuclei EW nuclei are parasympathetic motor nuclei for CN III EW activation leads to pupillary constriction

10. Parasympathetic Efferent Pathway EW nucleus → oculomotor nerve (III) → inferior branch → ciliary ganglion Postganglionic short ciliary nerves → sphincter pupillae Mediates light and near constriction

11. Near (Accommodation) Response Triggered by convergence and accommodation demand Involves cortical input → EW nucleus (light‑near dissociation possible) Produces miosis + accommodation + convergence

12. Sympathetic Efferent Pathway Hypothalamus → descends to ciliospinal center (C8–T1) Preganglionic fibers ascend in sympathetic chain → SCG Postganglionic fibers travel with carotid plexus to eye

13. Sympathetic Pathway: Key Landmarks First‑order: central (hypothalamus to brainstem/cord) Second‑order: preganglionic (spinal cord to SCG) Third‑order: postganglionic (SCG to iris dilator)

14. Pupillary Light Reflex: Stepwise Light → retina → optic nerve → pretectal nucleus Bilateral EDW activation → CN III → constriction of both pupils Direct and consensual responses explained

15. Why Consensual Response Occurs Pretectal nuclei project bilaterally to both EW nuclei Light in one eye activates both sides → both pupils constrict This is the basis for testing direct & consensual reflexes

16. Exam: Inspection Note size, shape, symmetry, and reactivity Assess in both bright and dim lighting Look for irregularities: peaking, ovalization, coloboma

17. Exam: Direct & Consensual Light Reflex Shine light in one eye → observe both pupils Direct: same eye constricts; Consensual: opposite eye constricts Document degree and latency

18. Swinging Flashlight Test (RAPD) Move light rapidly between eyes while observing pupils A relative afferent pupillary defect = Marcus Gunn pupil Affected eye shows less constriction when light swung toward it

19. Measuring Anisocoria Compare pupil sizes in bright and dim light Small anisocoria (<1 mm) can be physiologic Larger differences suggest pathology—localize by lighting condition

20. Light vs Dark Localizing Rule If anisocoria greater in light → larger pupil cannot constrict (parasympathetic problem) If anisocoria greater in dark → smaller pupil cannot dilate (sympathetic problem)

21. Relative Afferent Pupillary Defect (RAPD) Indicates asymmetric afferent input (retina or optic nerve) Not a pupil size asymmetry—it's about input strength Best detected with swinging flashlight test

22. Causes of RAPD Optic neuritis, severe retinal disease, optic nerve compression Large retinal detachments or extensive ischemia Lesions anterior to optic chiasm are typical

23. Third Nerve (Oculomotor) Palsy Features: ptosis, 'down-and-out' eye, possible dilated pupil Pupil involvement suggests compressive lesion (aneurysm/tumor) Pupil-sparing palsy more typical of microvascular ischemia

24. Pupil-Sparing vs Pupil-Involving III Nerve Microvascular ischemia → somatic fibers affected, parasympathetic spared Compression (PCom aneurysm, uncal herniation) often compresses peripheral parasympathetic fibers → dilated pupil

25. Horner Syndrome: Triad Miosis (small pupil), mild ptosis, ipsilateral facial anhidrosis (variable) Results from interruption of sympathetic pathway Localize lesion by associated signs and pharmacologic testing

26. Horner Localization Central lesions: brainstem or cervical cord (often with other neuro signs) Preganglionic: chest/neck causes (trauma, Pancoast tumor) Postganglionic: carotid dissection or cavernous sinus pathology

27. Pharmacologic Testing Overview Used to confirm and localize Horner's or to test pupil receptors Common agents: cocaine, apraclonidine, dilute pilocarpine, phenylephrine Interpretation depends on expected physiologic response

28. Cocaine Test (Horner's) Cocaine blocks norepinephrine reuptake → normal pupil dilates Horner's eye fails to dilate → confirming sympathetic denervation Has logistical and availability limitations

29. Apraclonidine Test (Horner's) Weak alpha‑agonist; denervated pupil shows supersensitivity → dilation Often used as alternative to cocaine test Interpret with caution in infants and glaucoma patients

30. Dilute Pilocarpine (Adie’s Testing) Very dilute (0.1%) pilocarpine causes constriction in denervated (Adie) pupil Normal pupil does not react to dilute solution Helps distinguish Adie’s tonic pupil from pharmacologic blockade

31. 1% Pilocarpine (Pharmacologic Blockade) Strong pilocarpine will constrict normal and many abnormal pupils Lack of response suggests pharmacologic blockade (e.g., anticholinergic exposure) or iris sphincter damage

32. Phenylephrine Test 1%–10% phenylephrine can dilate a postganglionic Horner pupil (supersensitivity) Also used to test for autonomic denervation or to reverse pharmacologic miosis

33. Adie (Tonic) Pupil Unilateral, dilated pupil with poor light response but better constriction for near Associated with decreased deep tendon reflexes in Holmes‑Adie syndrome Denervation supersensitivity demonstrable with dilute pilocarpine

34. Argyll Robertson Pupil Small, irregular pupils that accommodate but do not react to light ('prostitute pupil') Classically associated with neurosyphilis (but other causes exist) Light‑near dissociation is the hallmark

35. Pharmacologic Mydriasis Topical anticholinergic exposure (atropine, scopolamine) causes fixed dilated pupil History and topical testing help differentiate from neurologic causes 1% pilocarpine typically will not constrict a pharmacologically dilated pupil

36. Traumatic Mydriasis & Sphincter Damage Direct iris sphincter injury from blunt trauma can cause persistent dilation Slit‑lamp exam may reveal sector paralysis or iris tears Surgical repair considered in symptomatic cases

37. Posterior Synechiae and Iridocyclitis Inflammation can cause pupillary irregularity and fixed distorted pupil May be associated with reduced reactivity due to adhesions Manage underlying uveitis to release synechiae

38. Coloboma & Aniridia Congenital defects that alter pupil shape or absence of iris tissue Often part of syndromes—screen for systemic associations Pupil size and light reactions may be abnormal

39. Wernicke's Hemianopic Pupil Relative pupillary findings associated with homonymous hemianopia Careful visual field assessment and neuroimaging required Mechanism relates to asymmetric afferent input

40. Hippus (Pupillary Oscillations) Spontaneous rhythmic fluctuations in pupil size Usually benign and physiologic but may be accentuated in certain conditions Document if prominent

41. Light‑Near Dissociation: Causes Parinaud's (dorsal midbrain) syndrome, Argyll Robertson, Adie's tonic pupil Characterized by poor light reflex but preserved near response Localize lesion accordingly

42. Parinaud’s (Dorsal Midbrain) Syndrome Vertical gaze palsy, lid retraction, light‑near dissociation Causes include pineal tumors, midbrain lesions, MS Requires neuroimaging

43. Internuclear Pathways & Pupils MLF lesions affect conjugate gaze more than pupils Consider broader brainstem localization with gaze palsies Pupil findings help refine lesion localization

44. Pupils in Optic Neuritis Often associated with RAPD if unilateral optic nerve inflammation Pupil size may be normal or slightly altered Management targets underlying demyelination

45. Raised Intracranial Pressure & Pupils Uncal herniation can compress CN III → dilated pupil(s) Progressive change in reactivity is a red flag in head injury Serial pupil checks are crucial in neurocritical care

46. Pupil Assessment in Emergency Settings Quick direct/consensual check and size measurement Serial checks to monitor deterioration (e.g., intracranial hemorrhage) Document findings clearly with timestamps

47. Pupil Charting & Documentation Record size (mm), reactivity, symmetry, and test used Use terms: brisk, sluggish, nonreactive, reactive to accommodation Photograph or video if useful for serial comparison

48. Diagnostic Algorithm: Anisocoria (Overview) Step 1: Is anisocoria greater in light or dark? Step 2: Look for ptosis, motility deficits, anhidrosis Step 3: Apply pharmacologic testing when needed

49. Algorithm: RAPD Approach Confirm RAPD with swinging flashlight test Localize to retina/optic nerve if RAPD present Proceed with OCT, fundoscopy, neuroimaging as indicated

50. Imaging & Investigations MRI/CT brain and orbits when intracranial or compressive lesion suspected Carotid imaging if postganglionic Horner's suspected (dissection) OCT, visual fields, and fundus exam for retinal/optic nerve disease

51. Management Principles (General) Treat underlying cause (inflammation, infection, tumor) Symptomatic measures for diplopia or photophobia Refer for neuroimaging or specialty care when red flags present

52. Surgical Interventions Iris repair for traumatic defects or large colobomas Synechiolysis for posterior synechiae Consider cosmetic or functional surgery for persistent anisocoria

53. Pharmacologic Management Examples Apraclonidine for symptomatic Horner's in some cases Pilocarpine for pharmacologic reversal rarely used clinically Topical agents can be therapeutic or diagnostic

54. Prognosis & Follow‑Up Prognosis depends on underlying etiology Some neuropathies recover (inflammatory), others may be permanent (sphincter rupture) Plan follow‑up and repeat testing

55. Pediatric Considerations Congenital anomalies (coloboma, aniridia) more common Examine carefully—use child‑friendly techniques Beware of leukocoria causes that can present with pupillary changes

56. Assessing Pupils in Children Use toys and fixation targets for cooperation Infrared pupillometry or photos may assist Consider referral for congenital anomalies workup

57. Pupils in the Elderly Smaller baseline pupils, slower reactivity Medications (e.g., anticholinergics) often contribute to abnormalities Consider systemic comorbidities (diabetes)

58. Special Tests: Pupillometry Infrared pupillometry gives objective measurements Useful for research and precise monitoring May detect subtle RAPD or pharmacologic supersensitivity

59. Teaching Tips: Clinical Exam Always test in both light and dark conditions Perform swinging flashlight test before bright light fatigue occurs Document consistently

60. High‑Yield Exam Points RAPD = afferent lesion (retina/optic nerve) Larger pupil in light suggests parasympathetic lesion Third nerve palsy with pupil involvement = likely compression

61. Common Pitfalls Misinterpreting physiologic anisocoria as pathologic Not checking anisocoria in both lighting conditions Assuming fixed dilated pupil is always neurologic rather than pharmacologic

62. FAQ: Quick Answers Q: When is imaging urgent? A: New pupil dilatation with other neuro signs or severe headache Q: Can topical drops cause persistent change? A: Yes, depending on agent and exposure

63. Case Study 1: Acute Unilateral Dilated Pupil Presentation: sudden dilated pupil + headache Consider: subarachnoid hemorrhage, PCom aneurysm, pharmacologic cause Immediate steps: neuro exam, emergent imaging

64. Case Study 2: Anisocoria Greater in Dark Smaller pupil cannot dilate → suspect Horner syndrome Look for ptosis and anhidrosis, perform apraclonidine/cocaine testing Search for carotid dissection if clinically suspected

65. Case Study 3: Small Pupil with Ptosis Consider Horner's vs miotic drug exposure Check history, systemic symptoms, and test with apraclonidine Plan imaging if red flags present

66. Flowchart: Approach to Anisocoria (Slide 1) Start: measure in bright and dim light Branch based on which lighting widens anisocoria Follow to targeted pharmacologic or imaging tests

67. Flowchart: Approach to RAPD (Slide 2) Confirm RAPD → localize to optic nerve/retina → order OCT/visual fields/fundoscopy If unexplained, consider neuroimaging

68. Investigations: Ophthalmic Tests Fundoscopy, OCT RNFL and macula, visual fields Slit‑lamp exam to look for iris defects or synechiae Tonometry when indicated

69. Investigations: Neurologic Tests MRI brain/orbit with contrast when compressive or inflammatory disease suspected CT angiography for suspected aneurysm or carotid dissection EMG/nerve conduction rarely helpful for pupil alone

70. Management: When to Refer Urgent neuro referral for new dilated pupil with other neuro signs Ophthalmology referral for traumatic iris injury or uveitis Neurology/specialist referral for complex autonomic disorders

71. Rehabilitation & Visual Aids Tints or contact lenses for anisocoria photophobia Occlusion or prisms for diplopia management Counseling for cosmetic concerns

72. Prognosis Examples Optic neuritis: RAPD may improve with treatment Traumatic sphincter rupture: often permanent without repair Horner's from dissection: prognosis depends on underlying cause

73. Pupil‑Related Systemic Associations Neurosyphilis (Argyll Robertson), diabetes (III nerve ischemia) Pancoast tumor (preganglionic Horner), carotid dissection (postganglionic Horner) Consider systemic history and symptoms

74. Drug Table (Appendix) Cocaine: diagnostic for Horner's (dilation absent in affected eye) Apraclonidine: alternative for Horner's (dilates denervated pupil) Pilocarpine (dilute): diagnostic for Adie’s tonic pupil

75. Glossary (Appendix) Anisocoria: unequal pupils RAPD: Relative Afferent Pupillary Defect EW: Edinger–Westphal nucleus

76. Mnemonics & Memory Aids 'Light in → both constrict' reminds bilateral EW projection 'Anisocoria worse in dark → sympathetic problem' (simple rule) Use clinical vignettes to reinforce localization

77. Appendix: Suggested Diagrams (placeholders) Pupillary light reflex schematic — see AAO pupillary pathways (recommended) Sympathetic chain schematic — see Wikimedia Commons examples

78. Appendix: Example Images (placeholders) Insert: retinal afferent pathway diagram (suggested source: Optic nerve images) Insert: ocular motor nerve cross‑section (recommended: Wikimedia)

79. References (Primary sources) EoPhtha - Pupillary Pathway and Abnormalities (original referenced page). AAO — Pupillary Pathways image & notes. Eyewiki & related ophthalmology resources.

80. References (Additional) Slideshare and open PPTs on pupillary pathways (educational) Course materials (university PDFs) and Optometry resources

81. Acknowledgments Content compiled from standard ophthalmology and neuro‑ophthalmology sources Slides created by ChatGPT‑assisted authoring (original wording)

82. Author / Contact Prepared for: Priyank Rao Contact: add your email or institution here

83. Image Placeholders / How to Insert Images If you can provide original images I will embed them into this PPT Alternatively download free images from the suggested links and insert manually I can re-run and add images if you upload them to chat

84. End Slide / Thank You Questions? Use this slide to start discussion or Q&A session

85. Extra: Sample Algorithm Diagram (placeholder) Insert flowchart image here — suggested creation in PowerPoint using shapes Use this slide to paste a diagnostic flowchart image

86. Extra: Sample Clinical Photo Placeholder 1 Insert clinical pupil photo — ensure patient consent before use Suggested free sources: Wikimedia Commons clinical images

87. Extra: Sample Clinical Photo Placeholder 2 Insert retinal or optic nerve imaging showing RAPD correlate Label clearly and include source attribution