Optic disc evaluation

1. Sujay Chauhan
OPTIC DISC
EVALUATION

2. TERMINOLOGIES
Optic disc - Intraocular portion of optic nerve. Termination of all retinal layers
except nerve fibres, which pass through lamina cribrosa into the optic nerve.
Optic nerve head - Optic disc along with underlying pre-laminar layer of optic
nerve and region of lamina cribrosa
Optic papilla - Slightly elevated periphery of optic disc.
Physiological cup - Depression seen in optic disc

3. GENERAL FEATURES
Shape
Circular or ovoid
Location
Centre of disc lies 4 mm nasally and 1 mm superiorly to fovea
Colour
• Optic cup is white - due to lamina cribrosa and medullated nerve fibres behind it
and absence of vascular choroid
• Neural rim is yellow-pink - rich capillary network
• Fair-skinned, blond, myopic people with large optic discs have a light coloured
discs, and vice versa

4. Zones of the optic nerve head and peripapillary pigmentation
CUP
NRR
SCLERAL LIP
ZONE β
ZONE α

5. Margin
• Nasal margin - not well defined
• Margins at superior and inferior poles and in small optic discs - obscured due to
crowding of nerve fiber bundles
• Choroidal crescent - gap in RPE revealing underlying choroid because of oblique
insertion of optic nerve and tilting of disc
• Scleral crescent - when both RPE and choroid are deficient
• Both crescents mostly arise on temporal aspect of disc

6. Dimensions
Vertical diameter = 1.8 mm
Horizontal diameter = 1.5 mm
Depth = 1 mm
Cup : Disc ratio - Ratio of vertical diameter of optic cup
to that of optic disc
May vary from 0.1 - 0.9
Correction factors for estimating optic disc diameter:
Volk +78 D = 1.1 x
Volk +90 D = 1.3 x
ISNT rule - Inferior NRR is broadest followed by superior, nasal and temporal
Small and moderate sized optic discs follow the rule, large discs may not

7. • Physiologic cupping - horizontally oval and deeper in nasal quadrant
• Only 2 % of normal population have C:D ratio > 0.7
• Number of optic nerve fibres, and area of neural rim they comprise, is constant.
Thus, small optic discs have small cup because of concentration of nerve fibres
at their point of confluence
• Small discs - 0.35
Large discs - 0.55
• Early glaucomatous changes can be missed in small discs
Cupping over diagnosed in large discs

8. Retinal vessels on and near optic disc
• CRA enters globe through physiological cup - divides dichotomously within cup
and on surface of disc - 4 branches (ST, SN, IT, IN)
• May divide within optic nerve head - 2 or 4 branches emerging separately from
within the physiological cup
• Veins lie temporal to arteries
• Cilioretinal artery - in 40% people and emerge from temporal aspect of optic
disc

9. Spontaneous vascular pulsations
• Venous pulsation - seen at sharp bend in the vein as it turns into lamina cribrosa
• Absent in 20% healthy people
• Can be elicited by elevating IOP by pressing gently on globe
• Indication of normal ICP, if IOP is normal
• Can be seen in presence of elevated ICP if IOP is high
• Arterial pulsation - raised IOP or elevated pulse pressure

10. Other important observations
• Copper-wire appearance - reflection of light at vessel centre
• Relative sizes of arteries and veins (normally - 2:3)
• Thickening of arterioles - ageing, arteriosclerosis, hypertension
• Very narrow, thready arterioles - tapetoretinal degenerations
• Changes at AV crossings

11. OPTIC DISC ANOMALIES
SMALL OPTIC DISC
• Hypermetropia
• Aphakia
• Tilted optic disc
• Optic disc hypoplasia
LARGE OPTIC DISC
• High myopia
• Congenital optic disc pit
• Optic disc coloboma
• Morning glory anomaly
• Megalopapilla

12. NON-PROGRESSIVE CONGENITAL OPTIC DISC ANOMALIES
COLOBOMA
• Enlarged optic disc, partially or almost totally excavated
• Deepest part of coloboma is usually situated inferiorly
• Glistening white, tinged with grey on its surface
• Increased number of blood vessels cross border of coloboma - represent
branches of central retinal vessels which have divided on optic disc surface
before reaching retina
• Peripapillary pigmentary changes (hyper or hypo)

13. TILTED OPTIC DISC / NASAL FUNDUS ECTASIA SYNDROME /
FUCH'S COLOBOMA / DYSVERSION OF THE OPTIC DISC
• Usually inferiorly or inferonasally
• Choroidal or scleral crescent
• Situs inversus - in 80% of eyes with tilted disc. Temporal retinal vessels first turn
nasally before curving temporally towards macula

14. OPTIC DISC PIT
• Round or oval
• Pigmented (usually)
• 1 pit per optic disc, occasionally 2 or 3
• Size = 1/4 - 1/2 DD
• Larger optic disc with distinct physiological cup
• Base of pit may pulsate - underlying blood vessels, or transmission from
subarachnoid space
• Peripapillary chorioretinal atrophy
• Retinal vessels cross the pit - running superficially or dipping below its surface
• 60% cases - cilioretinal artery arises from periphery of pit
• Serous RD develops in 30% cases - resolves spontaneously

16. APLASIA AND HYPOPLASIA
• Abnormally small optic disc with pathologically low number of nerve fibers
• Grey or pale
• Double ring sign - peripapillary halo bordered by ring of increased or
decreased pigmentation
• Deficit visual function

17. ALTITUDINAL HEMIHYPOPLASIA
• Hypoplasia restricted to upper half of disc
• In children of severe diabetic mothers with poor control during pregnancy
• Little or no visual field below horizontal meridian
MICROPAPILLA
• Smaller optic disc
• Blurred margins
• Small or absent cup
• Normal visual function

18. MEGALOPAPILLA / MACROPAPILLA
• Extraordinarily large optic disc
• Very large central cup and narrow but healthy neuroretinal rim
• Bilateral
• Peripapillary pigmentary changes may be present
• Normal optic nerve function

19. MORNING GLORY OPTIC DISC
• Enlarged, nearly circular optic disc containing a deep conical depression with
white to pink glial tissue at its base
• Grey or black halo
• Retinal vessels loop over the edge of optic disc in a radial fashion (origin and
early branching obscured by glial tissue)
• Serous RD - may fluctuate and resolve spontaneously

20. MYELINATED NERVE FIBRES
• 1% of normal population
• Not present at birth; develop post-natally
• White, highly reflective lesion with feathery margins. Dark slits within the
lesion represent normal, unmyelinated fibres

21. CONGENITAL VASCULAR ANOMALIES
PERSISTENT HYALOID ARTERY
• Bloodless, transparent, thread-like remnant extending forwards from optic disc
• Portion near the disc may contain blood
Anteriorly the artery may retain its attachment to posterior lens capsule - Mittendorf's dot

22. BERGMEISTER'S PAPILLA (PERSISTENT HYPERPLASTIC PRIMARY
VITREOUS)
• Faint grey or yellow-white protuberance over the optic disc
• Nasally in 90% cases
• Physiological optic cup is reduced or absent

23. PREPAPILLARY VASCULAR LOOPS
• Short and simple, or may be long with several spiral twists
• Never reach the posterior surface of lens
• Loop usually originates from, and returns to the vessels on the optic disc;
occasionally may arise from an artery on disc and return to a retinal branch
• Arterial loops generally affect inferior central retinal vessels (may pulsate)
• Venous loops usually affect superior retinal veins

24. ACQUIRED VASCULAR ANOMALIES
NEOVASCULARISATION AT DISC
• Fine network of vessels lying flat on disc or protruding into vitreous
• Do not branch dichotomously
Causes -
• Proliferative diabetic retinopathy
• Retinal vein occlusion
• Old retinal artery occlusion
• Ocular ischemic syndrome
• Radiation retinopathy
• Carotid-cavernous fistula

25. DISC HAEMORRHAGES
• Acute papilloedema
• Arteritic AION
• Papillitis
• Diabetic papillopathy
• Chronic glaucoma
• Optic disc drusen

26. OPTIC NEURITIS
RETROBULBAR NEURITIS
Early phase - disc appears normal; later - primary optic atrophy

27. PAPILLITIS
• Early phase - disc is moderately swollen and hyperemic
• Indistinct margins
• Splinter haemorrhages on the disc surface
• Later - secondary optic atrophy
NEURORETINITIS
• Early phase - disc may appear swollen; later - consecutive optic atrophy

28. OPTIC NEUROPATHY
RETROBULBAR OPTIC NEUROPATHY
Early phase - disc appears normal; later - primary optic atrophy
ISCHEMIC PAPILLOPATHY
Acute phase - swollen and pale optic disc (usually sectorial), superficial splinter
haemorrhages
Chronic phase - secondary optic atrophy
ARTERITIC PAPILLOPATHY
Features same as in ischemic papillopathy

29. DIABETIC PAPILLOPATHY
• Optic disc may be hyperemic and swollen, indistinct margins
• In severe cases – papilledema

30. LEBER'S HEREDITARY OPTIC NEUROPATHY
• Swollen and hyperaemic optic disc
• Dilated telangiectatic capillaries mainly on, and extending from, temporal side
of optic disc
• Chronic stage - secondary optic atrophy, marked reduction in vascularity

31. OPTIC ATROPHY
PRIMARY OPTIC ATROPHY
• Chalky white optic disc with clearly defined margins
• Disc pallor, more on temporal side
• Atrophied neural rim - loss of physiological cup and flattening of optic disc
• No gliotic or vascular changes

32. SECONDARY OPTIC ATROPHY
• Grayish white swollen optic disc
• Poorly defined margin
• Partially or completely filled physiological cup
• Gliotic changes may or may not be present

33. CONSECUTIVE OPTIC ATROPHY
• Pale yellow, waxy looking flat optic disc
• Well defined margins
• Minimal gliotic changes
• e.g. Retinitis pigmentosa
CAVERNOUS OPTIC ATROPHY OF SCHNABEL
• Seen in ischemic lesions of optic nerve head
• Diffusely enlargement and bean pot like cupping

34. PERIPAPILLARY ATROPHY
Alpha Zone:
• Hypo and hyper-pigmented areas
• Present in glaucomatous as well as non-glaucomatous eyes
Beta Zone:
• Large choroidal vessels become visible
• Larger beta zone often has thin NRR in the same area
• More common in glaucomatous eyes and progression of beta zone is
associated with glaucoma progression

35. MYOPIA
• Optic disc is sometimes distorted
• Tilting of optic disc, usually temporally
• Retinal vessels appear dragged
• Nasal vessels curve around the elevated nasal sector of disc, temporal vessels
pursue a straightened course
• Myopic crescent

36. HYPERMETROPIA
• Small, pink optic disc, appears elevated and congested, but capillaries are not
dilated
• Central retinal vessels crowd the centre of small optic disc; spontaneous venous
pulsation not affected
• Severe cases - horizontal choroidal folds in peripheral fundus

37. GLAUCOMA
Focal atrophy
• Polar notching - small, discrete neural atrophy, usually in inferotemporal
quadrant
• Selective loss of neural rim tissue in inferotemporal and superotemporal
sectors - vertical or oblique enlargement of cup
• With progression temporal neural rim is involved followed by nasal quadrant
• Bayoneting sign - Retinal vessel bending sharply at the edge of disc
Concentric atrophy
• Less common
• Begins temporally, progresses circumferentially - temporal unfolding

38. LARGE OPTIC DISC WITH LARGE
PHYSIOLOGIC CUPPING
GLAUCOMATOUS CUPPING
Preserved healthy NRR widest at inferior
pole and narrowest in temporal quadrant
(I>S>N>T)
Cup extends to the disc margin

39. Deepening of cup
• Overpass cupping - vessels initially bridge the deepened cup, later collapse into it
• Laminar dot sign - Exposure of underlying lamina cribrosa. Fenestration with
striate appearance has higher association with glaucomatous damage than dot-
like appearance
Pallor/cup discrepancy
• In early stages of glaucomatous optic atrophy - size of cup > area of pallor
• Other causes of optic atrophy - area of pallor > size of cup
• Area of cupping recognized by observing kinking of vessels at cup margin
• Saucerisation - diffuse, shallow cupping extending to disc margins
• Focal saucerisation - localized shallow, sloping cup, usually in inferotemporal
quadrant
• Tinted hollow - normal NRR colour in area of focal saucerisation
• Shadow sign - grayish hue of NRR

40. Advanced glaucomatous cupping
• Total cupping - white disc with loss of all neural rim tissue
• Bending of vessels at disc margin

41. Optic disc haemorrhages
• NTG > COAG
• Most commonly in inferior quadrant
• Resolve spontaneously and reappear at same or different location
• Cross the disc margin - papillary portion often disappears first during
resorption, leaving the appearance of an extrapapillary haemorrhage
• Decline in frequency with advanced damage
• Associated with progressive changes of visual field
Peripapillary pigmentary disturbance
• Scleral lip or peripapillary halo
• Peripapillary atrophy (both zone beta and zone alpha)

42. PAPILLOEDEMA
Early phase
• Swollen optic disc with indistinct margin
• First seen in nasal quadrant and then in superior and inferior sectors (because
of variation in density of nerve fibres in NRR)
• Physiological cup is maintained giving the disc a cylindrical appearance
• Disc is hyperemic due to capillary dilatation
• Retinal veins are congested and non-pulsatile
• Circumpapillary accumulation of fluid - concentric retinal folds (Paton’s lines)
and choroidal folds (best seen with red-free filter)

43. Acute phase
• Optic disc becomes increasingly swollen and elevated
• Physiological cup may still be maintained
• Retinal venous congestion more pronounced.
• Some blood vessels partially obscured at the edge of disc
• Flame-shaped haemorrhages on disc margin
• Macular star - accumulation of fluid and exudates, most prominent on nasal
aspect of macula

44. Long standing phase
• Disc markedly swollen and physiological cup obliterated – Champagne cork
appearance
• Circulatory adjustments lead to resolution of venous congestion and retinal
edema

45. Atrophic stage
• Pale optic disc (Secondary optic atrophy)
• Neuronal degenerative changes - punctate white opacities in superficial nerve
fibre layer
• Attenuated retinal arteries
• Circumpapillary choroidal pallor and RPE atrophy with areas of pigmentary
clumping

46. OPTIC DISC DRUSEN
Children
• Small optic disc
• Drusen hidden within substance of nerve head
• Pseudopapilledema
• Retinal veins not distended, spontaneous retinal pulsation not affected
• Central retinal vessels may show anomalous branching (10% cases)
• Cilioretinal arteries commonly occur

47. Adolescents and adults
• Drusen - single or multiple, glistening, semi-translucent; may coalesce – give
disc a yellow-pink appearance
• Optic disc may become enlarged and its border indistinct or irregular
• Physiological cup is obliterated
• Splinter haemorrhages on disc surface, subretinal haemorrhages in
peripapillary area

48. TUMOURS AND TUMOUR-LIKE CONDITIONS
MELANOCYTOMA
• Grey to jet-black
• Eccentrically placed on optic disc, extending over disc margin
• Optic disc adjacent to the tumour is normal, may be swollen

49. ASTROCYTIC HAMARTOMA
• Early stage - Smooth semi-translucent mass
• Mature stage - Mulberry-like white reflective mass, may become calcified
• Very vascular; blood vessels can be seen coursing through their substance

50. CAPILLARY HAEMANGIOMA
• Localised, round, orange-pink
• Vascular
• Situated eccentrically on disc overlapping the disc margin and extending
forwards into vitreous

51. CAVERNOUS HAEMANGIOMA
• Grape-like saccular aneurysms lying flat on the retina
• Circulation through haemangioma is sluggish and blood tends to stagnate in
each saccule, with red blood cells sedimenting in response to gravity, leaving
a pale layer of plasma above

52. GLIOMA
• Smooth, elevated, white mass partially or completely obscuring the disc
• Compression of disc may cause occlusion of central retinal vessels
• Glioma situated posterior to lamina cribrosa may cause primary optic atrophy

53. MENINGIOMA
Direct involvement of optic nerve
• Elevated, pale mass obscuring the optic disc and displacing the peripapillary
retina
• Splinter haemorrhages may be seen over the surface of the mass
Optic nerve compression
• Pale, swollen optic disc
• Optociliary shunt vessels

54. OPTIC DISC GRANULOMA
Acute stage
• Raised, irregular, hyperaemic lesion affecting the optic disc and extending into
the adjacent retina
• Peripapillary sub-retinal fluid accumulation
Later stage
White mass of scar tissue overlying the disc causing traction retinal folds