Optic Disc: Anatomy, Variants, Unusual discs. Kathleen B. Digre, MD Professor Neurology, Ophthalmology

Transcription

1 Optic Disc: Anatomy, Variants, Unusual discs Kathleen B. Digre, MD Professor Neurology, Ophthalmology

2 THE OPHTHALMOSCOPE

3 DIRECT OPHTHALMOSCOPY Jan Purkinje 1823 Hermann von Helmholtz 1851 Hand held ophthalmoscope Direct up-right image

4 Dials of the Ophthalmoscope

5 RED-FREE FILTER (GREEN LIGHT) 450 nm monochromatic light nerve fiber layer optic nerve drusen

6 OTHER DIALS Used for measuring lesion size Looking for the center of fixation

7 OTHER DIALS: SLIT BEAM

8 The wheel has lenses of power

9 Steps to Direct Ophthalmoscopy Dimly lit room Dilating drops Patient fixates distant target Align yourself Red reflex Dial in

10 The layers you will go through to see the optic disc

11 THE OPTIC NERVE

12 THE NORMAL DISC The disc is 1.62 mm or 1 million fibers Central retinal artery and vein Lamina Cribrosa The optic cup

13 WHAT YOU SHOULD OBSERVE IN EVERYONE

14 The Normal Disc Appearance

15

16 NO CUP 0.1 CUP 0.3 CUP 0.7 CUP 0.9 CUP

17 NERVE FIBER LAYER

18 NORMAL NERVE FIBER LAYER

19 NERVE FIBER LAYER: TOTAL LOSS

20 NERVE FIBER LAYER: WEDGE LOSS

21 NERVE FIBER: RAKE DEFECTS

22 VASCULAR SUPPLY TO THE GLOBE AND DISC TWO MAJOR SOURCES by way of the ophthalmic artery+ Posterior Ciliary arteries Central retinal artery

23 BLOOD SUPPLY TO THE DISC is from the posterior ciliary arteries The posterior ciliary arteries supply the disc, the choroid and the retinal pigment epithelium

24 BLOOD SUPPLY TO THE DISC The central retinal artery supplies the retina

25 CILIORETINAL ARTERY Present in about 32% of patients Enters separate from the CRA Occlusion with swollen nerve = Temporal arteritis Spared in CRAO

26 straight Hook edge disc margin Hook from disc Hook from juxtapapillary region Tasman and Brown, Congenital Anomalies of The optic disc. 1983; 82

27 DISCS THAT ARE ONLY CILIORETINAL ARTERIES? WHAT SYSTEMIC ANOMALY SHOULD YOU LOOK FOR? A: Renal dysplasia: Papillo-renal syndrome Barroso LH, Hoyt WF, Narahara M. Can the arterial supply of the retina in man be exclusively cilioretinal? J Neuroophthalmol Jun;14(2):87-90.

28 VASCULAR VARIATIONS TRIFURCATIONS CONGENITAL TORTUOSITY

29 VENOUS DRAINAGE OF THE GLOBE

30 VENOUS ANOMALIES Edge Veins of Kraupa- All venous drainage one vein Barroso L, Hoyt WF, Narahara M. Disc edge veins of Kraupa: rare exit anomalies of the retinal vein. BJO 1992;76:442-3

31 Congenital Acquired after CRVO Other conditions? Optic meningioma CRVO Glaucoma Glioma Sarcoid Chronic papilledema Congenital Retino-choroidal collaterals

32 PAPILLEDEMA FEATURES OF TRUE SWELLING Hyperemia Swelling of nerve fibers Elevation disc margin Maintenance of cup if present Loss of venous pulse INCIDENTAL FINDINGS Hemorrhages Retinal folds Nerve Fiber Layer infarcts

33 FEATURES DISTINGUISH TRUE PAPILLEDEMA FROM PSEUDOPAPILLEDMA PAPILLEDEMA Physiologic cup present Vessels are normal Hyperemia Diffuse elevation Retinal veins dilated Exudates No SVP PSEUDOPAPILLEDEMA Absent cup Vessels arise from center Disc color normal Elevation irregular Veins not dilated No exudates SVP

34 VENOUS PULSATIONS

35 Normal variations

36 MYOPIC DISC

37 HYPEROPIC DISCS

38 LITTLE RED DISCS Frequently confused for papilledema Discs at risk Frequently hyperopic May be hypoplastic

39 Megallopapilla Rarely associated with what condition? Optic n glioma

40 MYELINATED NERVE FIBERS Developmental abnormality when the myelin goes beyond the lamina cribrosa Feathered edge Usually no effect on vision

41 What is left behind and how the eye is made affects the appearance of the disc Bergmeister Papilla

42 Pre-papillary arterial convolutions Retinal arterioles NOT a-v; Multiple arteriolar loops No visual loss unless they bleed Pre-papillary arterial loop

43 TILTED DISCS

44

45 Tilted discs: Visual field cuts (refractable)

46 OPTIC DISC DRUSEN An inherited anomaly that is often confused with papilledema

47 VISIBLE DRUSEN

48 BURIED DRUSEN

49 IMAGING DRUSEN AUTOFLUORESCENCE CT APPEARANCE (not MRI)

50 OPTIC DISC HYPOPLASIA confused with optic atrophy Very common optic disc anomaly The double ring sign Vision is affected Usually seen in children of diabetic mothers Look for pituitary dysfunction

51 Hypoplasia OPTIC NERVE HYPOPLASIA

52 Optic Nerve Hypoplasia: (not DeMorsiere s Syndrome) (optic n hypoplasia, (absent septum pellucidum) and dwarfism) Look for DI, GH deficiency Hypothyroidism, hypo-corticoidism, Growth retardation Vision variable Seen in drug use alcohol phenytoin Maternal infections Diabetes Think midline Defects with hypopituitarism Thinning/absence of cc small chiasm Pituitary may be absent Agensis of corpus Collosum; absent septum pellucidum

53 Segmental hypoplasia TOPLESS DISCS What association? Diabetes

54 From Unoki, Ohba, Hoyt, Br J Ophth 2002; 86;

55 COLOBOMA MEANS GAP Failure of closure of the embryonic fissure

56 OPTIC DISC COLOBOMA Usually inferior Disc may appear enlarged Pigmentary changes around defect common Think cardiovascular, CNS defects, nasopharyngeal

57 What associations To consider? Trans-sphenoidal Encephalocele

58 COLOBOMAS Amblyopia Trans-sphenoidal and other encephaloceles WHEN COLOBOMAS ARE BILATERAL THINK: CHARGE = COLOBOMA + Heart Atresia Choanae Retarded Growth and Development Genital Hypoplasia Ear Anomalies

59 Double discs?

60 OPTIC DISC COLOBOMA: CT

61 MORNING GLORY DISC White central tissue Excavated nerve; halo surrounds Vessels radial WHAT ASSOCIATIONS? Basal encephalocele Vascular dysgenesis: Moya Moya

62

63 OPTIC DISC PITS What complications Can occur from Pits? Serous Detachments

64 VIEW THE DISC WITH CONFIDENCE IDENTIFY NORMAL STRUCTURES differentiate variants from disc swelling or atrophy Look for disc anomalies Know anomalies that have systemic associations

65 NOVEL URL

66 1. 50 yo man with headache-- transient obscurations in the right eye 2. What is the disc abnormality?

67 2. 9 yo asymptomatic boy referred for papilledema by optometrist 3. Is this papilledema?

68 3. Headache and visual loss in the right eye 6. What is the disc anomaly?

69 4. Two different patients--what is this? 7. Name this anomaly

70 5. Which disc is abnormal? 6. Name the disc defect? 7. What structure will you look for on an MRI? 8. In a child, what test would you order?

71 9. What is the disc anomaly? 10. What tests will you order?

72 11. WHAT IS THE ANOMALY? 12-14: List 3 causes

73 15. What artery is occluded?

74 16. Name the defect 17. Name a condition associated with the defect

75 18. Name the defect 19 What condition associated with defect?

76 20. NAME A RESOURCE WHERE YOU CAN LOOK AT A LOT OF DISC Anomalies!