Efficacy of Plasma Exchange Treatment for Demyelinating Optic Neuritis

Purpose: To evaluate the value of plasma exchange (PE) for patients with three subtypes of demyelinating optic neuritis (ON): aquaporin-4 (AQP4)-antibody positive ON (AQP4-ON), myelin oligodendrocyte glycoprotein (MOG)-antibody positive ON (MOG-ON), and AQP4 and MOG-antibody double-seronegative ON (D-ON). Methods: A prospective study compared the logMAR best-corrected visual acuity (BCVA) at most severe onset, 1 day before IVMP treatment, 1 day before PE treatment, after five-cycles of PE therapy, and at 1-, 3-, and 6-month follow-up visits. The proportions of eyes in each visual outcome category were also compared. Logistic regression and a receiver operating characteristic curve were used to analyze predicted factors for VA improvement. Results: A total of 124 ON attacks of 122 patients were included, but 95 AQP4-ON patients suffering 96 attacks, the mean logMAR BCVA markedly improved and was steadily maintained after five-cycles of PE treatments (adjusted p ＜ 0.001). BCVA also improved in two of 6 MOG-ON patients, but no significant improvement in 22 D-ON attacks (p = 0.659). Combination of the number of previous ON episodes and the time window to PE treatment showed an accuracy of 74.7% for prediction of BCVA to improve ≥ 2 scores. In addition, a combination of logMAR VA before PE and the time window to PE treatment resulted in 83.4% accuracy to predict whether VA would regain 1.0 logMAR. Conclusions: PE therapy effectively improves visual outcomes for AQP4-ON patients but offers limited value for D-ON patients. Early initiation greatly increases the likelihood of achieving VA improvement.