Background: To evaluate the effect of high-dose intravenous steroids, as well as normobaric oxygen therapy, in the management of recent onset non-arteritic anterior ischemic optic neuropathy (NAION).
Method: Ninety eyes of 90 patients diagnosed with NAION within 14 days of onset were included in this single masked randomized clinical trial. Thirty patients were randomized into each set as group 1 (control), group 2 (steroids), and group 3 (oxygen). Controls received placebo; group 2 received methylprednisolone 500 mg twice a day for 3 days followed by 2 weeks of oral prednisolone 1 mg/kg/day; group 3 received 100 % normobaric oxygen with mask, at a flow rate of 5 liters per minute for 1 hour twice a day for two weeks. Functional and structural outcomes were analyzed at 1 and 6 months following treatment. Best corrected visual acuity (BCVA) was the main outcome measure, and mean deviation (MD) of visual field (VF) test and peripaillary retinal nerve fiber layer thickness (PRNFLT) were secondary outcome measures.
Results: The mean BCVA at the time of presentation was 1.02 ± 0.63, 1.05 ± 0.7, and 0.76 ± 0.5 LogMAR in groups 1, 2, and 3, respectively (p = 0.293); corresponding values were 0.8 ± 0.45, 0.84 ± 0.45, and 0.58 ± 0.4 at month 1 (p = 0.127, 0.19, and 0.168, respectively). BCVA improved to 0.71 ± 0.46, 0.73 ± 0.36, and 0.59 ± 0.41 LogMAR at the 6-month follow-up point (p = 0.039, 0.048, and 0.195, respectively). The mean deviation (MD) at the time of presentation was 19.26 ± 7.02, 20.51 ± 4.68, and 19.3 ± 7.17 in the control, steroid, and oxygen groups, respectively (p = 0.65). Corresponding values at month 1 were 20.26 ± 8.52, 19.52 ± 7.08, and 18.3 ± 7.45, (p = 0.656); and at month 6 were 18.42 ± 8.17, 17.66 ± 6.44 and 16.53 ± 6.32, respectively (p = 0.635). PRNFLT at presentation was 166 ± 57, 184 ± 57, and 193 ± 65 micrometer in the control, steroid, and oxygen groups, respectively (p = 0.265); which decreased to 73 ± 11, 87 ± 26, and 79 ± 19 at the final foll-w up (all p < 0.001). There were no statistically significant differences between the three groups in terms of final visual function and structure.
Conclusion: The lack of demonstrable improvement in the structural and functional outcomes of NAION with high-dose IV steroids, or normobaric oxygen, in this randomized controlled trial calls into question the administering of systemic steroid or normobaric oxygen in this condition.
Keywords: Erythropoietin; NAION; Neuroprotection; Normobaric oxygen therapy.