Aquaporin-4 Serostatus and Visual Outcomes in Clinically Isolated Acute Optic Neuritis

Aquaporin-4 antibodies (AQP4-Ab) are associated with neuromyelitis optica spectrum disorder (NMOSD) and typically this disorder has a poor visual prognosis as a result of optic neuritis (ON). Our aim was to report the clinical features at onset and final visual outcomes at 6 months of patients with ON who were positive for AQP4-Ab vs. those who were negative for AQP4-Ab.

Retrospective cohort study. AQP4-Ab were tested by indirect immunofluorescence in 57 patients with a first episode of ON. All patients initially were referred for consideration of multiple sclerosis ON (MSON), NMOSD, or any other inflammatory central nervous system disorder during follow-up (41.31 ± 24.32 months). Our patients were diagnosed as having NMOSD, MSON, chronic relapsing inflammatory ON, and single isolated ON. Risk factors associated with visual outcomes of ON patients were assessed through an ordinal regression model.

Positive AQP4-Ab were associated with male sex (P = 0.02), earlier age of onset (P = 0.01), and myelitis relapses (P = 0.04). Seronegative group had fewer recurrences of ON than the seropositive group (35% vs 58%, P = 0.14). Patients that were positive for AQP4-Ab did not have worse visual acuity at baseline and after 6 months. However, poor visual acuity during first attack was associated with a worse visual acuity at 6 months (odds ratio = 2.28, 95% CI [1.58-3.28], P = 0.03).

At 6 months, positive AQP4-Ab vs negative AQP4-Ab patients no evidence of poorer visual acuity. Lower visual acuity at baseline was associated with poor visual recovery at 6 months.