Patients diagnosed with NAION within 14 days of onset were included. Patients were randomized into 3 groups. Group 1 or control consisted of 30 patients who received gelatinous capsules filled with sugar as placebo. Group 2 or steroid consisted of 30 patients received methylprednisolone (Solu-Medrol, Pharmacia Pharmaceutical Company, Belgium) 500 mg twice a day for 3 days followed by 2 weeks of oral prednisolone 1mg/kg/day. Thirty patients in group 3 or oxygen received 100% normobaric oxygen with face mask in sitting position, at a flow rate of 5 liters per minute for 1 hour twice a day for two weeks Functional and structural outcomes were assessed at 1 and 6 months following treatment. Best corrected visual acuity was the main outcome measure, and mean deviation index of visual field test and peripapillary retinal nerve fiber layer thickness were secondary outcome measures.

Inclusion Criteria:

• Patients with recent onset ( within 2 weeks) of non-arteritic ischemic optic neuropathy

Exclusion Criteria:

• the presence of glaucoma, or any other ocular, neurologic, or systemic disease that may influence visual acuity and visual field; abnormal results in laboratory assessments, including an abnormally elevated erythrocyte sedimentation rate and positive serum C-reactive protein;
• a history of previous ocular surgery;
• a history of prior treatment of any type for NAION;
• systemic condition such as diabetes mellitus and poorly controlled hypertension