Anterior Ischemic Optic Neuropathy

Question 1

what supplies the optic nerve head

Answer 1

short posterior ciliary arteries from ophthalmic artery (ICA)

Question 2

what is the circle of Zinn-Haller

Answer 2

fed by short posterior ciliary arteries, branches of dial arterial network, and choroidal vessels

Question 3

what supplies the retina

Answer 3

choroidal circulation and branches of the central retinal artery from ophthalmic artery (ICA)

Question 4

what is the epidemiology of NAOIN

Answer 4

middle-aged and adult patients

Question 5

what is the pathogenesis of AION

Answer 5

acute ischemia of the optic nerve head

• histopath documentation of infarction, but not vasculopathy
• strong association with vascular risk factors

Question 6

what are the risk factors of AION?

Answer 6

atherosclerotic risk factors = smoking, HTN, DM
nocturnal hypotension
prothrombotic risk factors
ocular risk factors
sleep apnea syndrome
renal failure
preoperative ischemic optic neuropathy

Question 7

what are the presenting symptoms of AION

Answer 7

monocular painless loss of vision occurring over hours to days

• symptoms present upon awakening
• rarely occurs in both eyes at the same time
• prodromal ocular or systemic symptoms are atypical (suggestive of giant cell arteritis)

Question 8

what are the typical exam findings of AION

Answer 8

reduced visual acuity
dyschromatopsia (diminished color vision)
afferent pupillary defect
optic disc edema
peripapillary splinter hemorrhage
small optic cup with nerve crowding in unaffected eye

Question 9

what is the optic disc appearance in AION

Answer 9

hyperemic and segmental

- disc hyperemia with peripapillary splinter or flame hemorrhages and dilated telangiectatic capillaries

Question 10

what is the vision loss in AION

Answer 10

visual acuity loss with color vision correlating to degree of visual acuity loss

Question 11

what is on the differential diagnosis for AION

Answer 11

Giant Cell Arteritis

• prodrome of systemic symptoms known as polymyalgia rheumatic (jaw claudication, proximal myalgias and arthralgia, scalp tenderness, HA, fatigue)
• pallid disc edema
• requires temporal artery biopsy

Question 12

how is AION diagnosed

Answer 12

clinically - age, vasculopathic risk factors, pattern of visual loss, swollen disc

Question 13

what is the prognosis in AION

Answer 13

visual prognosis

• vision may deteriorate over first few days/weeks, but most stabilize or improve
• continued progression unusual
• disc edema resolves over 2-3mo, followed by optic atrophy; @6mo: disc appears diffusely pale

Question 14

what is the treatment of AION

Answer 14

aspirin for secondary prevention of vascular outcomes
BP management
corticosteroids are INEFFECTIVE