INTRODUCTION Optic nerve ischemia most frequently occurs at the optic nerve head, where structural crowding of nerve fibers and reduction of the vascular supply may combine to impair perfusion to a critical degree and produce optic disc edema. The most common such syndrome is termed anterior ischemic optic neuropathy(AION). Generally, AION is categorized as either arteritic (associated with temporal arteritis) or nonarteritic .

1. ISCHEMIC OPTIC
NEUROPATHIES
DR HASIKA RAVULA
FINALYEAR PG
MS OPHTHALMOLOGY
1

2. Definition:
▪ Acute, painless optic neuropathy occurring
predominantly in patients over 50 years of
age
2

3. ISCHEMIC OPTIC NEUROPATHIES
INTRODUCTION
▪ Optic nerve ischemia most frequently occurs at the optic
nerve head, where structural crowding of nerve fibers
and reduction of the vascular supply may combine to
impair perfusion to a critical degree and produce optic
disc edema.The most common such syndrome is termed
anterior ischemic optic neuropathy(AION).
▪ Generally, AION is categorized as either arteritic
(associated with temporal arteritis) or nonarteritic .
3

4. ▪ Optic nerve ischemia affects the intraorbital
portion of the nerve less frequently, with no visible
disc edema, and this has been termed posterior
ischemic optic neuropathy.
▪ A number of syndromes that share similar
characteristics also may be ischemic in origin, such
as diabetic papillopathy.
4

5. RELEVANTANATOMY AND
ETIOPATHOGENESIS
▪ To understand the pathogenesis completely, it is useful to review
the vascular supply of optic nerve.
▪ Optic nerve receives its blood supply primarily from the posterior
ciliary vessels with scant contribution from the central retinal
vessels.
▪ The source and pattern of blood supply of the anterior part of the
optic nerve (also called the optic nerve head, ONH) is very
different from that of the posterior part.

6. ▪ The ONH is almost entirely supplied by the posterior
ciliary artery (PCA) circulation and the rest of optic nerve
posterior to the ONH is supplied from several other
sources.
▪ Hayreh in his pioneering work described in great detail the
blood supply of the visual pathways.
▪ The blood supply of the optic nerve can be subdivided into
the following parts, according to the different regions of
the optic nerve:

7. ARTERIAL BLOOD SUPPLY OFTHE ANTERIOR
PART OFTHE OPTIC NERVE (ONH)
▪ The ONH consists of, from front to back,
(i) surface nerve fiber layer,
(ii) prelaminar region,
(iii) lamina cribrosa region, and
(iv) retro-laminar region

8. 8

9. The Surface Nerve Fiber Layer
▪ This layer is mostly supplied by the retinal arterioles.
▪ In the temporal region, however, in some eyes, it may
instead be supplied by the posterior ciliary artery (PCA)
circulation from the deeper prelaminar region.
▪ The cilioretinal artery (an elongated posterior ciliary artery),
when present, usually supplies the corresponding sector of
the surface layer.

10. The Prelaminar Region
▪ This is situated in front of the lamina cribrosa.
▪ It is supplied by centripetal branches from the
peripapillary choroid.

11. Lamina Cribrosa
▪ This is supplied by centripetal branches from the short
PCAs, either directly or by the anastomotic arterial circle of
Zinn and Haller, when that is present.
▪ Contrary to the prevalent impression, the circle of Zinn and
Haller is not seen in every eye and, when seen, may be an
incomplete circle.
▪ The central retinal artery gives off no branches in this
region.

12. 12

13. Retrolaminar Region
▪ This is the part of the ONH that lies
immediately behind the lamina cribrosa.
▪ This part of the optic nerve is supplied by two
vascular systems, the peripheral centripetal and
the axial centrifugal systems.

14. Peripheral centripetal vascular system:
▪ This is seen in all nerves and forms the major source of supply to this
part.
▪ It is formed by recurrent pial branches arising from the peripapillary
choroid and the circle of Zinn and Haller (when present, or the short
PCAs instead).
▪ In addition, pial branches from the central retinal artery and other
orbital arteries also supply this part.
▪ The pial vessels give off centripetal branches, running in the septa of
the nerve.

15. Axial centrifugal vascular system :
▪ It is formed by inconstant branches arising from
the intra-neural part of the central retinal artery.
▪ However, it is not consistently present in all the
nerves.

16. ▪ From this description of the blood supply of the ONH
it becomes obvious that the main source of blood
supply to the ONH is the PCA circulation via the
peripapillary choroid and the short PCAs (or the circle
of Zinn and Haller).
▪ Fluorescein angiographic studies by Hayreh SS, et al
have shown a sectoral blood supply in the ONH,
which goes along with the overall segmental
distribution of the PCA circulation and also helps
explain the segmental visual loss in AION.

17. ARTERIAL BLOOD SUPPLY OFTHE
POSTERIOR PART OFTHE OPTIC NERVE
▪ This part of the optic nerve has a peripheral and an axial
vascular system.
Peripheral CentripetalVascular System:
▪ This is always present.
▪ It is formed by the pial vessels, which come from the collateral
arteries arising directly from the ophthalmic artery and some
of its intraorbital branches.

18. Axial CentrifugalVascular System:
▪ It is formed by branches of the central retinal artery, seen in 75
percent of cases, and the supply by the central retinal artery
may extend 1 to 4 mm behind the site of penetration of the
central retinal artery into the optic nerve and give rise to
centrifugal branches.

19. Inter-individualVariation in the Blood Supply of
the Optic Nerve Head
▪ There is a general impression that the pattern of blood supply
of the ONH is almost identical in all eyes, and that all ischemic
lesions can be explained by one standard vascular pattern.
▪ This fundamental error is responsible for a good deal of
confusion.
▪ Studies by Hayreh et al have clearly shown that ONH blood
supply shows a marked inter-individual variation, which is
produced by the following factors:

20. 1. Variation in the Anatomical Pattern of the Arterial
Supply
▪ The usual anatomical pattern is described above.
▪ However, there are tremendous variations in the anatomical
pattern and some of the differences in the vascular anatomy
reported in the literature can be explained on this basis.

21. 2.Variations in the Pattern of PCA Circulation
▪ From the account of the arterial supply of the ONH given
above, it is evident that the PCAs are the main source of
blood supply to the ONH.
▪ The PCAs show marked interindividual variation, which
must profoundly influence the blood supply pattern of the
ONH.
▪ A brief review of the work by Hayreh et al is detailed below:

22. (a) Variations in number of PCAs supplying an eye:
▪ There may be 1 to 5 between but usually 2 or 3 PCAs are
present.
▪ The PCAs enter the eyeball usually medial and lateral to the
optic nerve and hence are called medial and lateral PCAs

23. (b) In vivo supply by the PCAs:
▪ Hayreh et al have shown that PCAs and their branches have
a segmental distribution in vivo, in the choroid as well as in
the ONH.
▪ The lateral and medial PCAs supply the corresponding parts
of the choroid.
▪ However, there is marked inter-individual variation in the
area supplied by the PCAs in humans, both in the choroid
and in the ONH.

24. ▪ The medial PCA may supply the entire ONH, or it may take no
part in the blood supply of the ONH or there may be any number
of variations between these two extremes.
▪ The lateral PCA supplies the area of the ONH not supplied by the
medial PCA or vice versa.
▪ When there is more than one medial or lateral PCA, the area
supplied by each may be only a sector.

25. ▪ When the superior PCA is present, it accordingly supplies
a superior sector.
▪ Therefore, the inter-individual variation in number and
distribution by the various PCAs produces an extremely
variable pattern of distribution by the PCAs in the ONH.
▪ This is very important to keep in mind while dealing with
ischemic disorders of the ONH.
25

26. (c) Watershed zones in the PCA distribution and their location:
▪ When a tissue is supplied by two or more end-arteries, the border
between the territories of distribution of any two end-arteries is called
a “watershed zone”.
▪ The significance of the watershed zones is that in the event of a fall in
the perfusion pressure in the vascular bed of one or more of the end-
arteries, the watershed zone, being an area of comparatively poor
vascularistion is most vulnerable to ischemia.
▪ Since PCAs and their subdivisions are end-arteries in vivo, they have
watershed zones between them.

27. ▪ As discussed above, when there are two (medial and lateral)
PCAs, the area of the choroid and ONH supplied by the two
shows a marked inter-individual variation which results in
wide variation in the location of the watershed zone between
the two.
▪ When there are three or more PCAs supplying an eye, the
locations of the watershed zones vary according to the
number of the PCAs and their locations.

28. ▪ The location of the watershed zone in relation to the ONH is an
extremely important subject in any discussion of ischemic
disorders of the ONH.
▪ This is because in the event of fall of perfusion pressure in the
PCAs or their branches, the part of the ONH located in the
watershed zone becomes vulnerable to ischemia.

29. Fluorescein fundus angiograms of four eye with AION showing different locations of the watershed zone (vertical dark bands) in
relation to the optic disk. (A) Right eye with the watershed zone lying temporal to the optic disk. (B) Right eye with the
watershed zone passing through the temporal part of the disk and adjacent temporal peripapillary choroid. (C) Left eye with the
optic disk lying in the center of the watershed zone. (D) Left eye with the watershed zone passing through the nasal part of the
disk and adjacent nasal peripapillary choroid

30. (d) Difference in blood flow in various PCAs as well as short
PCAs:
▪ Clinical and experimental studies by Hayreh et al have
indicated that the mean blood pressure (BP) in the various
PCAs may be different in health and in disease.
▪ In the event of a fall of perfusion pressure, the vascular bed
supplied by one artery may be affected earlier and more than
the others.

31. ▪ Optic nerve ischemia most frequently occurs at the optic
nerve head, where structural crowding of nerve fibers and
reduction of vascular supply may combine to impair
perfusion to a critical degree.
▪ The blood flow in the optic nerve head depends upon
several factors, the most important of which is the blood
pressure in its vessels.

32. ▪ The blood flow in the ONH is calculated by using the following
formula (Hayreh et al):
Perfusion pressure = Mean BP – intraocular pressure (IOP).
Mean BP = Diastolic BP + 1/3 (systolic minus diastolic BP).
▪ From this formula, it is evident that the blood flow depends
upon (a) resistance to blood flow, (b) BP and (c) IOP.

33. ▪ Therefore, a reduction in blood flow may develop consequent to
alterations in one of these three factors.
▪ Transient poor circulation or loss of circulation in the optic nerve
head can occur due to a transient fall of blood pressure below a
critical level in its vessels, which in turn, in susceptible persons,
would produceAION.
▪ It is extremely important to remember that in this mode of
development ofAION there is no actual blockage of the posterior
ciliary arteries.

34. ▪ A fall of the blood pressure below the critical level in the
capillaries of the optic nerve head may be caused either by a
marked fall in blood pressure or by a rise in the eye pressure,
or a combination of these factors.
▪ Normally an autoregulation mechanism operates in the optic
nerve and helps compensate for any decrease in the blood
flow but autoregulation operates only over a critical range of
perfusion pressure so that with a rise or fall of perfusion
pressure beyond the critical range, the autoregulation
becomes ineffective and breaks down

35. Autoregulation in relation to the optic nerve blood flow

36. ▪ Factors that lead to the derangement of the autoregulation
in the ONH include some well known and some partly
known, systemic and local causes, including aging arterial
Hypertension, diabetes mellitus, marked arterial
hypotension due to any cause, arteriosclerosis,
atherosclerosis, hypercholesterolemia, and
hyperhomocysteinemia.

37. ▪ Thus, from the above discussion, it is evident that many
ocular and systemic risk factors may predispose to the
development of NAAION.
a. Ocular : Elevated IOP, small disk, presence of disk edema
b. Local vascular : Occlusion or stenosis of posterior ciliary
artery or ophthalmic artery (atherosclerosis, giant cell
arteritis).
c. Systemic : Hypotension, diabetes, hypertension, leukemia,
intake of contraceptive pills, hematological disorders like
polycythemia, sickle cell disease.

38. ANTERIOR ISCHEMIC OPTIC
NEUROPATHY (AION)
▪ Epidemiology
▪ Nonarteritic anterior ischemic optic neuropathy (NAION) is the
most common acute optic neuropathy in patients over 50 years
of age, with an estimated annual incidence in the United States
of 2.3–10.2 per 100 000 population.
▪ No gender predisposition exists, but the disease occurs with
significantly higher frequency inWhite than in Black or Hispanic
populations.
▪ The incidence of arteritic anterior ischemic optic neuropathy
(AAION) is significantly lower (0.36 per 100 000 population
annually in patients over 50 years of age).
38

39. Ocular Manifestations
▪ AION presents with rapid onset of painless, unilateral visual loss
manifested by decreased visual acuity, visual field, or both.
▪ The level of visual acuity impairment varies widely, from minimal
loss to no light perception, and the visual field loss may
conform to any pattern of deficit related to the optic disc.
▪ An altitudinal field defect is most common, but generalized
depression, broad arcuate scotomas, and cecocentral defects
also are seen.
▪ A relative afferent pupillary defect invariably is present with
monocular optic neuropathy.
▪ The optic disc is edematous at onset, and edema occasionally
precedes visual loss by weeks to months.
39

40. 40

41. ▪ Although pallid edema has been described as the hallmark
of AION, it is common to see hyperemic swelling,
particularly in the nonarteritic form.
▪ The disc most often is swollen diffusely, but a segment of
more prominent involvement frequently is present, and
either focal or diffuse surface telangiectasia is not unusual
and may be quite pronounced.
▪ Commonly, flame hemorrhages are located adjacent to the
disc, and the peripapillary retinal arterioles frequently are
narrowed.
41

42. 42

43. 43

44. 44

45. Arteritic anterior ischemic optic
neuropathy
▪ In 5–10% of cases, AION may occur as a manifestation of the
vasculitis associated with temporal arteritis.
▪ Patients with the arteritic form usually note other symptoms of
the disease – headache (most common), jaw claudication, and
temporal artery or scalp tenderness are those aligned most
frequently with a final diagnosis of temporal arteritis.
▪ Malaise, anorexia, weight loss, fever, proximal joint arthralgia,
and myalgia also are noted commonly; however, the disease
occasionally manifests with visual loss in the absence of overt
systemic symptoms, so-called occult temporal arteritis.
45

46. ▪ Typically, AAION develops in elderly patients, with a mean age of 70
years, with severe visual loss (visual acuity < 20/200 (6/60) in the
majority).
▪ It may be preceded by transient visual loss similar to that of carotid
artery disease; this finding is extremely unusual in the nonarteritic form
and, when present, is highly suggestive of arteritis.
▪ Pallor, which may be severe, chalky-white, is associated with the
edema of the optic disc more frequently in AAION than in the
nonarteritic form.
▪ Choroidal ischemia may be associated with the optic neuropathy and
produces peripapillary pallor and edema deep to the retina.
▪ The disc of the fellow eye is of normal diameter most frequently, with a
normal physiological cup.
46

47. Nonarteritic anterior ischemic optic
neuropathy
▪ In 90–95% of cases, AION is unrelated to temporal arteritis.
▪ The nonarteritic form of the disease occurs in a relatively
younger age group (mean age of 60 years) and usually is
associated with less severe visual loss.
▪ Frequently, visual impairment is reported upon awakening,
possibly related to nocturnal systemic hypotension.
▪ The initial course of visual loss may be static (with little or no
fluctuation of visual level after the initial loss) or progressive
(with either episodic or visual loss that declines steadily over
weeks to months prior to eventual stabilization).
47

48. ▪ The progressive form has been reported in 22% to 37% of
NAION cases. Usually, no associated systemic symptoms
occur, although periorbital pain is described occasionally.
▪ Fellow eye involvement is estimated to occur in 12–19% by 5
years after onset.
▪ Recurrent episodes of visual loss that result from NAION in the
same eye are unusual and occur most often in younger
patients.
48

49. ▪ The optic disc edema in NAION may be diffuse or segmental,
hyperemic or pale, but pallor occurs less frequently than it does
in AAION.
▪ A focal region of more severe swelling often is seen and typically
displays an altitudinal distribution, but it does not correlate
consistently with the sector of visual field loss.
▪ Diffuse or focal telangiectasia of the edematous disc may be
present.
▪ This finding may represent microvascular shunting from
ischemic to nonischemic regions of the optic nerve head, so-
called luxury perfusion.
49

50. ▪ The optic disc in the contralateral eye typically is small in
diameter and demonstrates a small or absent physiological
cup.
▪ The disc appearance in such fellow eyes has been described as
the disc at risk, with postulated structural crowding of the
axons at the level of the cribriform plate, associated mild disc
elevation, and disc margin blurring without overt edema.
50

51. (A) Fundus photograph of the right eye shows prominent
swelling of the disc with a disc rim hemorrhage. (B) Fundus
photograph of the left eye shows a healthy appearing but
crowded disc with a cup-to-disc ratio of 0.2.
51

52. Feature Arteritic AION Nonarteritic AION
Age (mean years) 70 60
Sex ratio Female > male Male = female
Associated symptoms Headache, scalp
tenderness, jaw
claudication
Pain occasionally noted
Visual acuity Up to 76% < 20/200
(6/60)
Up to 61% > 20/200
(6/60)
Disc Pale > hyperemic edema
Cup normal
Hyperemic > pale edema
Cup small
Mean erythrocyte
sedimentation rate
(mm/hour)
70 20–40
Fluorescein angiogram Disc and choroid
filling delay
Disc filling delay
Natural history Improvement rare
Fellow eye in up to 95%
Improvement in
up to 43%
Fellow eye in < 30%
Treatment Corticosteroids None proved52

53. 53

54. FUNDUS FLUORESCEIN
ANGIOGRAPHY
▪ In non-arteritic AION, during the very early stages of the
disease, angiography may show filling defects in the optic
disk.
▪ In contrast, peripapillary choroidal filling is not delayed.
▪ In arteritic AION this test is extremely helpful in making the
diagnosis because it shows that both the choroid and the
optic disk in the area supplied by the involved posterior
ciliary artery do not fill.

55. ▪ Since, arteritic and non-arteritic forms of the
ischemic optic neuropathy differ in the underlying
risk factors, it is extremely important to distinguish
between the two forms of the disease.

56. Diagnosis and AncillaryTesting
▪ The most important early step in the management of AION is
the differentiation of the arteritic from the nonarteritic form
of the disease.
▪ Measurement of the erythrocyte sedimentation rate (ESR) is
standard.
▪ Active temporal arteritis usually is associated with an elevation
of ESR to 70–120 mm/hour, and in acute AION that is associated
with other typical features, this finding suggests the arteritic
form; in most cases, it should prompt immediate corticosteroid
therapy and confirmatory temporal artery biopsy.
▪ The test has significant limitations, however, with normal
measurements found in an estimated 16% of biopsy-proved
cases.
56

57. ▪ Conversely, abnormally high readings occur normally with
increasing age and with other diseases, most commonly occult
malignancy, other inflammatory disease, and diabetes.
▪ Measurement of serum C-reactive protein (CRP), another
acute-phase plasma protein, may aid in diagnosis.
▪ Hayreh et al.reported 97% specificity for temporal arteritis in
cases of AION in which both ESR > 47 mm/hour and CRP >
2.45mg/dL were found.
57

58. ▪ Confirmation of the diagnosis of temporal arteritis by
superficial temporal artery biopsy is recommended in any
case of AION in which a clinical suspicion of arteritis exists
based on age, associated systemic symptoms, severity of
visual loss, and elevated ESR and CRP levels.
▪ Positive biopsy findings, such as intimal thickening, internal
limiting lamina fragmentation, and chronic inflammatory
infiltrate with giant cells, provide support for long-term
systemic corticosteroid therapy.
58

59. ▪ A negative biopsy result, however, does not rule out
arteritis; both discontinuous arterial involvement (“skip
lesions”) and solely contralateral temporal artery
inflammation may result in false-negative results.
▪ In the face of negative initial biopsy, consideration is given
to contralateral biopsy in cases with high clinical suspicion
of temporal arteritis.
59

60. 60

61. Differential Diagnosis
▪ The differential diagnosis of AION includes idiopathic optic
neuritis, particularly in patients under 50 years of age; other
forms of optic nerve inflammation, such as those related to
syphilis or sarcoidosis; infiltrative optic neuropathies; anterior
orbital lesions that produce optic nerve compression; and
diabetic papillopathy.
▪ Optic neuritis may resemble AION with regard to rate of onset,
pattern of visual field loss, and optic disc appearance.
▪ In most cases, however, the patient’s age, lack of pain with eye
movement, and pallor or segmental configuration of the disc
edema enables differentiation.
▪ Early disc filling delay on fluorescein angiography may confirm
ischemia.
61

62. ▪ Syphilitic or sarcoid-associated optic neuritis often is
associated with other intraocular inflammatory signs, which
should prompt further testing.
▪ Orbital lesions typically produce gradually progressive visual
loss.
▪ Associated signs of orbital disease, such as mild
exophthalmos, lid abnormalities, or eye movement
limitation, may suggest the use of neuroimaging to detect
anterior orbital inflammation or tumor.
62

63. Systemic Associations
▪ AAION is known to be a manifestation of temporal arteritis.
▪ NAION has been reported in association with a number of
diseases that could predispose to reduced perfusion pressure or
increased resistance to flow within the optic nerve head.
▪ Systemic hypertension has been documented in up to 47% of
patients who have NAION and diabetes in up to 24%.
63

64. ▪ Diabetics in particular show a predisposition to NAION at
a young age.
▪ Carotid occlusive disease, itself, does not appear to be
associated directly with NAION in most cases.
▪ However, indirect evidence shows increased central
nervous system, small vessel, ischemic disease in
patients who have NAION, based on magnetic resonance
imaging (MRI) data.
64

65. ▪ Early reports did not indicate that the incidence of prior or
subsequent cerebrovascular or cardiovascular events is
increased, but more recent studies indicate that they are both
more common than in the normal population, particularly in
patients who have hypertension or diabetes.
▪ Subsequent mortality, however, is not affected.
65

66. ▪ Also, NAION has been reported in association with multiple
forms of vasculitis, acute systemic hypotension, migraine,
optic disc drusen, and idiopathic vaso-occlusive diseases.
▪ Other risk factors, such as hyperopia, smoking, the presence
of human lymphocyte antigen A, and hyperlipidemia have
been proposed.
▪ Recent reports of the association of hyperhomocystinemia
with AION, particularly in patients under 50, are inconclusive.
▪ Prothrombotic risk factors, such as protein C and S and
antithrombin III deficiencies, factorV Leiden mutation, and
cardiolipin antibodies, do not seem to be associated with
AION.
66

67. Treatment
Arteritic anterior ischemic optic neuropathy
▪ Early treatment ofAAION is essential and must be instituted
immediately in any suspected case of temporal arteritis.
▪ High-dose systemic corticosteroids are standard; the use of
intravenous methylprednisolone at 1 g/day for the first 3 days
has been recommended forAAION when the patient is in the
acute phase of severe involvement, because this mode of
therapy produces higher blood levels of medication more
rapidly.
▪ Oral prednisone in the range of 60–100 mg/day may be used
initially and for follow-up to intravenous pulse therapy;
alternate day regimens do not suppress the disease effectively.
67

68. ▪ Treatment usually reduces systemic symptoms within
several days.
▪ A positive response is so typical that if it does not occur,
an alternate disease process should be considered.
▪ Treatment is usually continued at high dose for several
months before beginning taper.
68

69. Nonarteritic anterior ischemic optic neuropathy
▪ There is no proven effective therapy for NAION.
▪ Oral corticosteroids at standard dosage (1 mg/kg per day) are
not beneficial, and megadose intravenous therapy has not been
evaluated systematically.
▪ Optic nerve sheath decompression (ONSD) surgery has been
attempted, based on the theory that reduction of perineural
subarachnoid cerebrospinal fluid pressure might improve local
vascular flow or axoplasmic transport in the optic nerve head,
and thus reduce tissue injury in reversibly damaged axons.
▪ The Ischemic Optic Neuropathy DecompressionTrial compared
ONSD surgery in 119 patients with no treatment in 125
controls. 69

70. ▪ The study revealed no significant benefit for treatment and a
possible, although not proven, harmful effect; it was
recommended that ONSD not be performed for NAION.
▪ Hyperbaric oxygen, by marked elevation of the dissolved
oxygen content in the blood, provides increased tissue
oxygenation that might reduce damage in reversibly injured
axons.
▪ A controlled clinical pilot study of hyperbaric oxygen in 22
patients who had acute NAION, however, has shown no
beneficial effect.
70

71. ▪ Johnson et al.reported a beneficial effect for oral levodopa
on the visual outcome for NAION, but the study was
controversial, and the effect is considered unproved.
▪ Neuroprotective agents have shown a beneficial effect in
animal models of optic nerve damage, but are not proven
to be effective in NAION.
▪ The effect of aspirin in reducing risk of fellow eye
involvement is unclear.
71

72. Course and Outcome
Arteritic anterior ischemic optic neuropathy
▪ The major goal of therapy in AAION is to prevent visual loss in the
fellow eye.
▪ Untreated, such involvement occurs in 54–95% of cases, typically
within 4 months.
▪ With corticosteroid therapy, the rate of such breakthrough is
reduced to an estimated 13%.
▪ Prognosis for visual recovery in the affected eye that has treatment
generally is poor, but recent reports suggest a 15–34% improvement
rate, which is higher with intravenous than with oral therapy.
▪ Worsening of vision in spite of therapy has been reported in 9–17% of
cases. 72

73. Nonarteritic anterior ischemic optic neuropathy
▪ The course of untreated NAION varies considerably.
▪ Reports indicate that 24–43% of cases demonstrate
spontaneous improvement of visual acuity by three Snellen
lines or more.
▪ Even in the progressive form, improvement has been reported
to occur in roughly 30%.
▪ Whether NAION is static or progressive, visual acuity and field
stabilize after several months.
73

74. ▪ Within 6 weeks, occasionally sooner, the optic disc
becomes visibly atrophic, either in a sectorial or diffuse
pattern.
▪ Further progression or recurrent episodes are extremely
rare after 2 months and, if present, should prompt
evaluation for another cause of optic neuropathy.
74

75. 75

76. POSTERIOR ISCHEMIC OPTIC
NEUROPATHY
▪ Ischemia of the optic nerve that does not involve the optic
nerve head is termed posterior ischemic optic neuropathy
(PION).
▪ It presents with acute visual loss associated with signs of
optic neuropathy (afferent pupillary defect and visual field
loss) in one or both eyes, with initially normal appearance
of the optic disc, which subsequently becomes atrophic.
76

77. The diagnosis of PION is most often made in one of two
settings:
▪ 1.Vasculitis, most importantly giant cell arteritis (GCA);
evaluation for GCA should be the primary consideration with
this presentation in the elderly, or
▪ 2.The combination of systemic hypotension and anemia,
usually related to blood loss either from surgery (coronary
artery bypass and lumbar spine procedures most
commonly),gastrointestinal bleed, or trauma.
77

78. ▪ The differential diagnosis includes compressive,
inflammatory, and infiltrative optic neuropathies,
although the onset in PION is typically more abrupt.
▪ In most cases, neuroimaging is indicated to rule out
these possibilities.
78

79. ▪ Sadda et al.reported a multicenter, retrospective review of 72
patients with PION, adding a third classification paralleling the
nonarteritic form of AION.
▪ The nonarteritic PION group accounted for 38 of the 72
patients, exhibited similar risk factors, and followed a clinical
course precisely like that of NAION.
▪ In contrast to perioperative and arteritic PION, which were
characterized by severe visual loss with little or no recovery,
nonarteritic PION was less severe and showed improvement in
34% of patients.
79

80. ▪ It is important to recognize this nonarteritic form in
patients with acute optic neuropathy but no optic disc
edema, a scenario that may be mistaken for
retrobulbar optic neuritis.
▪ Such patients, particularly those with ischemic white-
matter lesions on MRI, might be incorrectly begun on
immunomodulatory therapy to reduce the risk of MS.
▪ PION differs from optic neuritis by its occurrence in
older age groups, with lack of pain on eye movements.
80

81. DIABETIC PAPILLOPATHY
PATHOGENESIS
▪ The pathogenesis of diabetic papillopathy is unclear.
▪ Early investigators postulated either a toxic effect on the optic nerve
secondary to abnormal glucose metabolism or a vascular disturbance
of the inner disc surface, similar to that which produces retinal edema,
with the resultant microvascular leakage into the disc.
▪ The most commonly proposed theory suggests diabetic
papillopathy to be a mild form of NAION, with reversible ischemia of
both the prelaminar and inner surface layers of the optic nerve head.
▪ Edema of the optic nerve head in the absence of significant visual
dysfunction and not secondary to elevated intracranial pressure occurs
in several presumed vascular disorders as follows:
81

82. ▪ Asymptomatic optic disc edema, which evolves to typical
NAION weeks to months after initial symptoms.
▪ Asymptomatic disc edema of the fellow eye in patients
who have NAION, which may either progress to NAION
or resolve spontaneously.
▪ Disc edema in association with systemic hypertension,
which resolves without sequelae as blood pressure is
normalized.
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83. ▪ Diabetic papillopathy fits this category, as well.
▪ The prominent surface telangiectasias may represent
vascular shunting from prelaminar to ischemic vascular
beds.
▪ The frequent occurrence of a crowded optic disc in the
fellow eye,as in NAION, also supports an ischemic
mechanism.
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84. OCULAR MANIFESTATIONS
▪ Early reports of diabetic papillopathy depicted the acute
onset of unilateral or bilateral disc edema in young, type
1 diabetics, without the usual defects in visual field and
pupillary function associated with NAION or optic
neuritis;a recent report included a substantial number of
older patients with type 2 diabetes.
▪ The currently accepted criteria for the diagnosis of
diabetic papillopathy include:
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85.  Presence of diabetes (approximately 70% type 1, 30%
type 2).
Optic disc edema (unilateral in roughly 60%).
Only mild optic nerve dysfunction.
▪ The absence of ocular inflammation or elevated
intracranial pressure also is essential to the diagnosis.
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86. ▪ Although younger patients predominate (approximately
75% of those reported are under the age of 50 years), those
affected may be of any age and typically experience either no
visual complaints or vague, nonspecific visual disturbance,
such as mild blurring or distortion; transient visual
obscuration has been reported rarely.
▪ Visual acuity is usually only mildly impaired; over 75% of
reported cases measured 20/40 (6/12) or better. Macular
edema contributes to visual acuity loss in many cases.
▪ Pain is absent, as are other ocular or neurological symptoms.
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87. ▪ The involved optic discs may demonstrate either nonspecific
hyperemic edema or, in approximately 55% of cases, marked
telangiectasia of the inner surface microvasculature; pale
swelling typically has been a criterion for exclusion and
suggests AION.
▪ The surface telangiectasia is so prominent in many cases that it
may be mistaken for neovascularization.
▪ True disc neovascularization occasionally is superimposed on
the edema of diabetic papillopathy.The fellow eye frequently
demonstrates crowding, with a small cup-to-disc ratio
similar to the configuration seen in patients who have NAION.
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88. OPTIC DISC IN DIABETIC PAPILLOPATHY
(A) Nonspecific hyperemic disc edema. 88

89. (B) Surface vessels show marked telangiectasia, in which dilated vessels
generally follow a radial distribution.
89

90. (C) Contrast with diabetic optic disc neovascularization; note
the irregular, random branching pattern of surface vessels. 90

91. ▪ Diabetic retinopathy usually is present (in more
than 80% of reported cases) at the time of onset of
papillopathy, but it varies in severity.
▪ It is associated with cystoid macular edema in
about 25% of cases and neovascularization in
approximately 9%.
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92. DIFFERENTIAL DIAGNOSIS
▪ Conditions that may simulate diabetic papillopathy include
papilledema (elevated intracranial pressure), hypertensive
papillopathy, optic disc neovascularization, papillitis, and NAION.
▪ Symptoms of elevated intracranial pressure usually differentiate
papilledema, and in bilateral cases with such symptoms, neuroimaging
and lumbar puncture must be considered.
▪ Disc edema related to systemic hypertension typically does not
demonstrate prominent telangiectasia and usually is associated with
hypertensive retinopathy; blood pressure measurement is
important in suspected cases.
▪ Papillitis and NAION both demonstrate significant optic nerve
dysfunction, as evidenced by afferent pupillary defect and visual field
loss.
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93. COURSE AND OUTCOME
▪ Although systemic corticosteroids have been used in isolated cases, no
proven therapy exists for this disorder.
▪ Untreated, the optic disc edema gradually resolves over a period of 2–
10 months, to leave minimal optic atrophy in about 20% of cases and
subtle, if any, visual field loss.
▪ Visual acuity at the time of resolution of edema is 20/40 (6/12) or better
in about 80% of cases; the remainder of patients suffer visual
impairment because of maculopathy.
▪ The long-term visual prognosis for patients who have diabetic
papillopathy, however, is limited by the associated diabetic
retinopathy.
▪ Proliferative changes, with attendant complications, develop in
approximately 25% of cases.
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94. THANKYOU….
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