ischemic optic neuropathy
TRANSCRIPT
BY-DR.. DIVYA PATEL
UPGRADED DEPARTMENT OF OPHTHALMOLOGY
MGM MEDICAL COLLEGE AND MYH, INDORE(M.P.)
BLOOD SUPPLY OF OPTIC NERVE HEAD
ISCHEMIC OPTIC NEUROPATHY It is circulatory insufficiency to optic nerve head
ISCHEMIC OPTIC
NEUROPATHY
ANTERIOR ISCHEMIC OPTIC
NEUROPATHY
ARTERITICNoNARTERIT
IC
POSTERIOR ISCHEMIC
OPTIC NEUROPATHY
ARTERITIC NON-ARTERITIC
POST
OPRETIVE
ANTERIOR ISCHEMIC OPTIC NEUROPATHY Most common cause of acute optic neuropathy in over
50 yr of age
It is due to ischemia of anterior part of optic nerve head
Involvement of posterior ciliary artery circulation
Considered in d/d of sudden vision of loss
Visual field loss always present
CLINICAL CLASSIFICATION Depending upon underlying cause,AION is of two
type-
ARTERITIC
• Most serious type
• Mainly due to gaint cell arteritis
NON-ARTERITIC
• Most common
• Consist of all other cause than GCA
CHARACTERISTIC ARTERITIC NONARTERITIC
AGE Over 70 yrs 60-70 yrs
SEX Females no
PRECEDING SYSTEMIC FEATURES
Jaw claudication,headache,scalptenderness
no
PRECEDING OCULAR SYMPTOMS
Highly suggestive Rare
VISUAL LOSS Highly suggestive 20% cases
PAIN Common Rare
SECOND EYE INVOLVEMENT
75% within days or weeks 40% in mths or yrs
DISC APPEARANCE Chalky white swollen disc Sectoral or pallid
FFA Choroidal filling defect Normal
ESR Raised Normal
CRP Raised Normal
TEMPORAL ART BIOPSY
Positive Negative
RESPONSE TO STEROIDS
definite Nil
NON-ARTERITIC AION M.C. cause of acute optic neuropathy
Over the age of 50 yr
PATHOGENESIS-
occlusion of short posterior ciliary artery
decreased blood supply to optic nerve head
infarction of optic nerve head
RISK FACTOR-multifactorial
Noctural arterial hypotension play very imp role
HTN/DM
H’RGIC SHOCK
VASOSPASTIC DISORDER
THYROID DS
COLLEGEN VASCULAR
DS
CARDIAC DS
Absent cup
Raised iop
Prolong pressure
on eyeball
Small cupSYSTEMIC OCULAR
CLINICAL FEATURES-
Sudden painless monocular loss of VA
Visual field defect usually inferior altitudinal but can central,paracentric,arcuate
Dyschromatopsia
Diffuse or sectoral disc swelling(pallid edema)
OD of other eye is typically small or absent cup
Frequently associated with spinter haemorrages
It is very imp to distingushed Non-arteriticAION with optic neuritis due to similar picture
NAION OPTIC NEURITIS
AGE >50 <40
PAIN unsual +nt
PUPIL +RAPD +RAPD
VISUAL FIELD DEFECT altitudinal central
OPTIC DISC Edema,may be pale Edema,hyperemic
RETINAL HEMORRHAGE
common unusual
FA Delayed disc filling No delayed
MRI SCAN No ON enhancement ON enhancement
INVESTIGATION-
Routine investigation
Lipid profile
BP &Cardiac evaluation
ESR(rule out arteritic AION)
MRI
Fluorescein fundus angiography In early stage shows filling defect in optic disc,peripapillarychoroid or choroidal watershed area
TREATMENT-
no proven definitive treatment
some proposed t/t –aspirin
levodopa or carbidopa
hyperbaric o2
topical- brimonidine
SURGICAL TREATMENT-
• Transvitreal optic neurotomy-nasal margin of disc widen the scleral canal
• Vitrectomy-to reduse episcleral traction
ISCHEMIC OPTIC NEUROPATHY DECOMPRESSION TRIAL (IONDT)
it shows no effect of surgery on visual outcome.
PROGNOSIS-
Optic disc become atrophic within 4-8wks
Rate of recurrence - same eye6.4%
fellow eye 10%after 2yr
& 15% after 5yr
When second eye involved,optic atrophy in one eye
and edema in other gives PEUDO-FOSTER-KENNEDY SYNDROME.(in contrast true foster
kennedy syndrome ,secondary to intracranial mass)
ARTERITIC AION It mainly caused by giant cell arteritis
Other rare cause-SLE
polyarteritis nodusa
herpes zoster
Mostly in age>55 yr female
b/l AION should suggest temporal arteritis
GCA is systemic vasculitis affecting large and medium sized arteries (intenal elastic lamina)
Mostly affects-
temporal
posterior ciliary
ophthalmic
vertebral arteries
CLINICAL FEATURES-
SYSTEMIC OCULAR
new onset of headache in older
Scalp tenderness,jawclaudication
Fever, anorexia, wt.loss,malaise
Polymyalgiarheumatica(proximal Ms)
Sudden ,profound u/l visual loss
May accompainedwith pain
May preceded by transient visual obscuration and flashing light
diplopia
Signs-
Chalky white oedematous disc (over 1-2 month optic atrophy ensues)
Cotton wool spots(never in NAION)
CRAO,OAO
Ocular ischaemic syndrome
PION can occurs
INVESTIGATION-
CBC
Blood platelet may elevated
ESR(westergren more reliable to wintrobe )
usually >60mm/hr,but in 10%,normal
C-reactive pretein
gold standard Temporal artery biopsy
done under local anesthesia ,2-3cm specimen to avoid skip lesion
FLUORESCEIN FUNDUS ANGIOGRAPHY-
Delay retinal and choroidal filling defect
disc stain in late stage
TREATMENT-Aim to prevent blindness of the fellow eye
Steroids- treatment of choice
oral prednisolone i/v methylprednisolone(80-120mg/d) (1g/d,3days)
‘ both are same effective’response seen by ESR &CRP
Antiplatelet therapy Immunosuppressives
PROGNOSIS-
Only 4% eyes with visual loss improved
Early,adequate steroid therapy prevent visual loss in 96%
POSTERIOR ISCHEMIC OPTIC NEUROPATHY Uncommon
Caused by reterobulbar O.N. ischemia(supplied by pialarteries)
Diagnosed only after exclusion of other reterobulbaroptic neuropathy
SUBTYPES-
• Within hours to days
• Mainly spinal.cardiac bypass sxPERIOPERATIVE
• Associated with GCA
• Poor visual prognosisARTERITIC
• Same risk factor of NAION
• Not associated with crowed optic disc
NONARTERITIC
PATHOGENESIS-
PION
DECREASED OXYGEN
CARRYING CAPACITY
HYPOTENSION
LEADS TO DECREASED PERFUSION PRESSURE
INCREASED RESISTANCE TO BLOOD FLOW
CLINICAL FEATURES-
Sudden,painless u/l or b/l vision loss
RAPD
Absence of optic disc edema
o Optic atrophy ensues in 4-6wk
INVESTIGATION-
Routine investigation
ESR
CT/MRI
VEP-shows decreased amplitude
TREATMENT-
• There is no effective treatment
• Some treatment methods were attempted-
corection of hemodynamic derangements
systemic corticosteroids
antiplatelet therapy
measures to lower IOP