• Neuro-Ophthalmology/Orbit

    Review of: MOG-Ab prevalence in optic neuritis and clinical predictive factors for diagnosis

    Ducloyer J, Caignard A, Aidaoui R, et al. British Journal of Ophthalmology, May 2020

    This multicenter, prospective study assessed the prevalence of myelin oligodendrocyte glycoprotein antibodies (MOG-Ab) among adults with optic neuritis (ON).

    Study design

    Researchers reviewed 65 patients (age>18 years) diagnosed with acute ON at 7 hospitals in western France over the course of 1 year. They excluded cases of noninflammatory optic neuropathy and any patient who did not undergo or have availability to MOG- or AQP4-antibody serological testing. Patients underwent neuroimaging and received intravenous steroids. Clinical data was collected on initial presentation and at 2 months. A masked junior radiologist and senior neuroradiologist retrospectively evaluated length of the optic nerve lesions and perineuritis of the optic nerve.

    Outcomes

    Approximately 14% of patients had MOG-Ab; this shifted to 13% after excluding patients with prior diagnoses of multiple sclerosis or MOG-Ab positivity. Overall, the prevalence of MOG-Ab was higher in men than women (29% vs. 7%) and in cases with optic nerve swelling (41% and 4%). Compared with a final diagnosis of multiple sclerosis and clinically isolated syndrome, MOG-positive ON occurred more often in men (67% vs. 22%), was often bilateral (44% vs. 3%) and associated with optic disc swelling (78% vs. 14%). These cases tended to be more painful than other types of ON (100% vs. 58%). Notable neuroimaging findings included optic nerve enhancement, optic nerve perineuritis with enhancement of the surrounding periorbital tissues and longitudinal optic nerve lesions.

    Limitations

    The current study only evaluated a single geographic region (France) over 1 year. There is likely variability in the results worldwide based on types of antibody testing available and reporting rates of incidences.

    Clinical significance

    This study confirms that MOG-Ab-positive optic neuritis is more common than NMOSD (14% vs. 2%). Other studies, however, estimate prevalence of this condition to be between 10% and 31%, with higher rates in Asia. These authors recommend testing MOG serology only in patients with optic nerve swelling, bilateral optic neuropathy or recurrent optic neuropathy to limit testing while minimizing missing potential positive cases. Cost-effective medicine is an important priority and having guidelines to support when to perform tests are crucial. International studies are needed to better inform testing in global health settings.