Fig. 1: Flow diagram of participants, illustrating exclusions and quality control steps.

The figure describes the exclusion and inclusion criteria used in the UK Biobank (UKBB) population. The boxes in the last row show the number of participants within each group: healthy controls (yellow), MS without ON (MS only, blue), MS-associated ON (MS-ON, purple), and ON without MS (ON only, red). An extended version is available in the supplement, which describes sources of diagnoses in more detail (Supplementary Fig. 1). UKBB UK Biobank, QC quality control, ON optic neuritis, MS multiple sclerosis.