NEFL and optic papillitis: In this group, CSF-NfL ratios were lower when compared to IIH patients with papilledema at the time of examination (papilledema, n = 23, mean CSF-NfL ratio = 1.7; no papilledema, n = 10, mean CSF-NfL ratio = 0.9, p = 0.02, unpaired t-test).