A Multicenter Prospective Diagnostic Accuracy Study of the 2022 International Criteria for Optic Neuritis and an Antibody-Stratified Adjunct in Acute or Subacute Visual Loss When Optic Neuritis Is Suspected in China

This is a multicenter prospective observational diagnostic accuracy study conducted in China. Structured prospective electronic case report form-based data collection for the primary diagnostic accuracy cohort began on January 6, 2025. The study population includes individuals with a new acute or subacute episode of visual loss or optic nerve-related visual dysfunction in one or both eyes, for whom optic neuritis is included in the initial differential diagnosis at participating clinical centers. Each participant contributes only one clinical episode to the primary diagnostic accuracy cohort.

The main objective is to evaluate the diagnostic performance of the 2022 International Criteria for Optic Neuritis in a real-world Chinese clinical setting. The study is also designed to evaluate the 2022 International Criteria for Optic Neuritis with a prespecified antibody-stratified adjunct strategy designed for settings where aquaporin-4 immunoglobulin G-positive optic neuritis and myelin oligodendrocyte glycoprotein immunoglobulin G-positive optic neuritis are relatively common and antibody testing is clinically available.

Baseline clinical data are collected prospectively using a structured electronic case report form. The form captures demographic information, symptom onset, laterality, pain with eye movement, visual acuity, protocol-defined color vision assessment, relative afferent pupillary defect assessment, and other predefined clinical variables.

Paraclinical data are collected when obtained as part of routine clinical care. These data may include visual field testing, optical coherence tomography, orbital or optic nerve MRI, serum aquaporin-4 immunoglobulin G, serum myelin oligodendrocyte glycoprotein immunoglobulin G, and other laboratory or imaging results. Optical coherence tomography is encouraged for objective structural characterization when clinically feasible, but it is not mandated by study participation. Follow-up optical coherence tomography at 3 to 6 months is encouraged when clinically feasible. Available follow-up optical coherence tomography data will be summarized descriptively. Exploratory optical coherence tomography-available analyses may be performed if data are sufficient; these analyses are not required for the primary diagnostic accuracy analysis. MRI and antibody testing are performed when considered clinically appropriate by the treating clinical team.

The 2022 International Criteria for Optic Neuritis serve as the index test. Index-test classifications will be assigned using baseline clinical data and paraclinical data eligible for application of the 2022 International Criteria for Optic Neuritis that were obtained within 3 months after symptom onset for the current clinical episode, based on the timing of the examination or sample collection. Follow-up information obtained after this diagnostic window will not be used to revise the index-test classification. Participants will be classified as definite optic neuritis, possible optic neuritis, or not optic neuritis according to prespecified rules. A prespecified antibody-stratified adjunct strategy, based on our published adjunct framework, will then be applied in combination with the 2022 International Criteria for Optic Neuritis, rather than as a standalone diagnostic test. This adjunct strategy incorporates aquaporin-4 immunoglobulin G seropositivity and clear-positive myelin oligodendrocyte glycoprotein immunoglobulin G results together with objective optic nerve evidence. The detailed operational rules are specified in the study protocol and are based on the cited published framework.