NAION produces an ischemic insult in the optic nerve head presumably due to the hypoperfusion of the short ciliary arteries that supply it.

Intravenous injection of glucocorticoid have proven to be effective in treatment of Nonarteritic Anterior Ischemic Optic Neuropathy,but have some side effects. the investigators believe that offering them Retrobulbar Triamcinolone Acetonide Injection that might halt the progression of the visual acuity and visual field loss if our hypothesis is correct, would greatly improve their chances of avoiding blindness.

Inclusion Criteria:

Sudden mono ocular vision loss associated with optic disc edema and positive Marcus Gunn (<30 days)

Exclusion Criteria:

Any eye disease except NAION(Nonarteritic Anterior Ischemic Optic Neuropathy) Neurologic defect Abnormal ESR, CRP, any history of retina or vitreal surgery Severe corneal opacity which makes retina examination impossible