Prospective Evaluation of the 2022 Optic Neuritis Criteria When Optic Neuritis Is Suspected (GX-ICON)

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

Optic neuritis is an important cause of acute or subacute visual loss. In clinical practice, optic neuritis must often be distinguished from other optic neuropathies, retinal diseases, anterior-segment or ocular media disorders, non-organic visual loss, and other mimics. The 2022 International Criteria for Optic Neuritis were developed to standardize the diagnosis of optic neuritis, but their performance in Chinese clinical settings, where aquaporin-4 immunoglobulin G-positive and myelin oligodendrocyte glycoprotein immunoglobulin G-positive optic neuritis are relatively common, remains uncertain.

This multicenter prospective observational study is enrolling patients with acute or subacute visual loss in whom optic neuritis is included in the differential diagnosis. The study is designed to evaluate the diagnostic performance of the 2022 International Criteria for Optic Neuritis alone and with an antibody-stratified adjunct. The index classifications will be compared with an expert-adjudicated reference-standard diagnosis. No experimental treatment is assigned by the study. All diagnostic tests and treatments are determined by the treating clinicians according to routine clinical care. Study data are collected using a structured protocol-defined case report form.

Study Overview

• Status: Recruiting
• Conditions: Optic Neuritis; Optic Neuropathy; Visual Loss

Detailed Description

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.

Participants are followed for up to 6 months after enrollment whenever feasible. Follow-up information includes available information on subsequent clinical course, repeat ophthalmic assessments, additional imaging or laboratory results, treatment response, and alternative diagnoses made during routine clinical care. This follow-up information will be used to support the expert-adjudicated reference-standard diagnosis. Participants for whom the reference-standard adjudication committee cannot assign a diagnosis of optic neuritis or non-optic neuritis because of insufficient clinical, imaging, laboratory, or follow-up information will be classified as indeterminate according to prespecified adjudication rules. Indeterminate reference-standard cases will be summarized separately and excluded from the primary binary diagnostic accuracy analysis.

Follow-up information beyond the prespecified index-test diagnostic window will be used for reference-standard adjudication only.

The reference-standard diagnosis will be determined by an expert adjudication panel. Two expert adjudicators will independently review the structured baseline clinical form and all available ophthalmic, imaging, laboratory, treatment, and follow-up information according to a prespecified adjudication process. The adjudicators will be masked to the 2022 International Criteria for Optic Neuritis classification and the antibody-stratified adjunct classification. They will not be masked to the source clinical, ophthalmic, imaging, laboratory, treatment, or follow-up information required for reference-standard adjudication. Disagreements will be resolved by a third expert adjudicator. Participants will be classified as optic neuritis, non-optic neuritis, or indeterminate. Cases with an indeterminate reference-standard diagnosis will be reported separately and will not be included in the primary diagnostic accuracy analysis. The initial agreement between the two expert adjudicators will be summarized using the percentage agreement and Cohen's kappa for the three-category reference-standard classification of optic neuritis, non-optic neuritis, or indeterminate.

The primary diagnostic accuracy analysis will compare the index-test classification with the expert-adjudicated reference-standard diagnosis. In the main analysis, definite optic neuritis will be classified as index-test positive and not optic neuritis will be classified as index-test negative. Possible optic neuritis will be treated as an indeterminate index-test category, excluded from the main binary diagnostic accuracy analysis, and reported separately. Key secondary analyses will evaluate the diagnostic yield of definite optic neuritis, the distribution of possible optic neuritis, the performance of a low-threshold definition that classifies definite or possible optic neuritis as index-test positive, and the performance of the 2022 International Criteria for Optic Neuritis with the antibody-stratified adjunct. Diagnostic measures will include sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratios, and 95 percent confidence intervals, as appropriate.

The study is observational. The investigators do not assign experimental treatment or alter routine clinical management. Treatment decisions, including corticosteroids, plasma exchange, immunosuppressive therapy, biologic therapy, or treatment for non-inflammatory alternative diagnoses, are made by the treating clinical team as part of routine clinical care and are not dictated by the study protocol.

At the time this record was initially submitted for public registration, recruitment was ongoing, and database lock, formal reference-standard adjudication, final index-test classification, and the primary diagnostic accuracy analysis had not occurred.

• Study Type: Observational
• Enrollment (Estimated): 500

Contacts and Locations

• Study Contact: Name: Yi Du, MD, PhD; Phone Number: +86 771 5356507; Email: duyinapoleon@gmail.com

Study Locations

• China
  • Guangxi
    • Nanning, Guangxi, China, 530021
      • Recruiting
      • The First Affiliated Hospital of Guangxi Medical University
      • Contact: Yi Du, MD, PhD; Phone Number: +86 771 5356507; Email: duyinapoleon@gmail.com
    • Nanning, Guangxi, China, 530005
      • Recruiting
      • The Second Affiliated Hospital of Guangxi Medical University
      • Contact: Wenqiao Huang; Phone Number: +86 771 3277068; Email: wqhuang8674@163.com
    • Nanning, Guangxi, China, 530001
      • Recruiting
      • Guangxi Minzu Hospital
      • Contact: Meifeng Luo; Phone Number: +86 771 3131152; Email: luomf9853@qq.com
    • Nanning, Guangxi, China, 530022
      • Recruiting
      • Guangxi Jingliang Eye Hospital
      • Contact: Mukun Zhao; Phone Number: +86 771 7980630
    • Nanning, Guangxi, China, 530199
      • Recruiting
      • Wuming Hospital of Guangxi Medical University
      • Contact: Xiaoyuan Ma; Phone Number: +86 771 6226473
      • Contact: Yihua Huang
    • Qinzhou, Guangxi, China, 535000
      • Recruiting
      • The Second People's Hospital of Qinzhou
      • Contact: Fangfang Zhang; Phone Number: +86 777 3682222
    • Wuzhou, Guangxi, China, 543099
      • Recruiting
      • Wuzhou Gongren Hospital
      • Contact: Jun Yang; Phone Number: +86 774 2036883
    • Yulin, Guangxi, China, 537099
      • Recruiting
      • The First People's Hospital of Yulin
      • Contact: Na Li; Phone Number: +86 775 2683288
      • Contact: Qingjuan Zhao
  • Jiangsu
    • Suzhou, Jiangsu, China, 215000
      • Recruiting
      • Lixiang Eye Hospital of Soochow University
      • Contact: Yinbin Tang; Phone Number: +86 512 69359692

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

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.

Description

Inclusion Criteria:

1. Individuals presenting 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 considered a reasonable differential diagnosis by the treating clinical team at the initial clinical assessment and before final diagnostic adjudication.
2. Symptom onset of the current episode within 90 days before enrollment.

Exclusion Criteria:

1. The participant has previously been enrolled in this study. Each participant may be enrolled only once.

A history of optic neuritis or recurrent optic neuropathy before the current episode is not an exclusion criterion.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Suspected Optic Neuritis Differential-Diagnosis Cohort; Individuals with acute or subacute visual loss or optic nerve-related visual dysfunction in whom optic neuritis is included in the differential diagnosis at initial clinical assessment. Participants undergo routine clinical evaluation, and study data are collected using a structured protocol-defined case report form. No treatment is assigned by the study. The 2022 International Criteria for Optic Neuritis will be evaluated alone and with the antibody-stratified adjunct as diagnostic index-test approaches.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Diagnostic Performance of the 2022 International Criteria for Optic Neuritis	Sensitivity, specificity, predictive values, likelihood ratios, and 95 percent confidence intervals will be assessed against the expert-adjudicated reference standard. Definite optic neuritis will be index-test positive and not optic neuritis will be index-test negative. Possible optic neuritis will be treated as an indeterminate index-test category and reported separately. Indeterminate reference-standard diagnoses will be excluded. Index-test classification will use eligible baseline and paraclinical data obtained within 3 months after symptom onset; later follow-up data will not revise the index-test classification.	Index-test data within 3 months after symptom onset; reference-standard diagnosis up to 6 months after enrollment

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Diagnostic Yield of Definite Optic Neuritis Classification	Proportion of participants with expert-adjudicated optic neuritis who are classified as definite optic neuritis by the 2022 International Criteria for Optic Neuritis.	Index-test data within 3 months after symptom onset; reference-standard diagnosis up to 6 months after enrollment
Diagnostic Performance of the Low-Threshold 2022 Criteria Definition	Sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratios, and 95 percent confidence intervals when definite optic neuritis or possible optic neuritis is classified as index-test positive and not optic neuritis is classified as index-test negative.	Index-test data within 3 months after symptom onset; reference-standard diagnosis up to 6 months after enrollment
Diagnostic Performance of the 2022 International Criteria for Optic Neuritis With the Antibody-Stratified Adjunct	The antibody-stratified adjunct will be applied in combination with the 2022 International Criteria for Optic Neuritis, rather than as a standalone diagnostic test. Diagnostic performance of the combined criteria-plus-adjunct classification will be assessed against the expert-adjudicated reference standard. Participants with an indeterminate reference-standard diagnosis will be excluded from this binary diagnostic accuracy analysis.	Index-test data within 3 months after symptom onset; reference-standard diagnosis up to 6 months after enrollment
Proportion of Indeterminate Reference-Standard Diagnoses	Proportion of participants for whom the expert adjudication panel classifies the reference-standard diagnosis as indeterminate.	Up to 6 Months After Enrollment
Distribution of 2022 International Criteria for Optic Neuritis Classifications	Proportion of participants classified as definite optic neuritis, possible optic neuritis, or not optic neuritis by the 2022 International Criteria for Optic Neuritis.	Baseline and diagnostic-window data for the current episode, within 3 months after symptom onset

Collaborators and Investigators

• Sponsor: First Affiliated Hospital of Guangxi Medical University
• Investigators: Principal Investigator: Yi Du, MD, PhD, First Affiliated Hospital of Guangxi Medical University

Publications and helpful links

General Publications

• Liang Y, Yang J, Luo W, Wei S, Wang K, Song R, Fu R, Zhao Y, Bai Y, Du Y. Diagnostic yield of the 2022 optic neuritis criteria and an antibody-stratified adjunct in an antibody-predominant Chinese clinical sample. Mult Scler Relat Disord. 2026 Apr 25;111:107212. doi: 10.1016/j.msard.2026.107212. Online ahead of print.
• Petzold A, Fraser CL, Abegg M, Alroughani R, Alshowaeir D, Alvarenga R, Andris C, Asgari N, Barnett Y, Battistella R, Behbehani R, Berger T, Bikbov MM, Biotti D, Biousse V, Boschi A, Brazdil M, Brezhnev A, Calabresi PA, Cordonnier M, Costello F, Cruz FM, Cunha LP, Daoudi S, Deschamps R, de Seze J, Diem R, Etemadifar M, Flores-Rivera J, Fonseca P, Frederiksen J, Frohman E, Frohman T, Tilikete CF, Fujihara K, Galvez A, Gouider R, Gracia F, Grigoriadis N, Guajardo JM, Habek M, Hawlina M, Martinez-Lapiscina EH, Hooker J, Hor JY, Howlett W, Huang-Link Y, Idrissova Z, Illes Z, Jancic J, Jindahra P, Karussis D, Kerty E, Kim HJ, Lagreze W, Leocani L, Levin N, Liskova P, Liu Y, Maiga Y, Marignier R, McGuigan C, Meira D, Merle H, Monteiro MLR, Moodley A, Moura F, Munoz S, Mustafa S, Nakashima I, Noval S, Oehninger C, Ogun O, Omoti A, Pandit L, Paul F, Rebolleda G, Reddel S, Rejdak K, Rejdak R, Rodriguez-Morales AJ, Rougier MB, Sa MJ, Sanchez-Dalmau B, Saylor D, Shatriah I, Siva A, Stiebel-Kalish H, Szatmary G, Ta L, Tenembaum S, Tran H, Trufanov Y, van Pesch V, Wang AG, Wattjes MP, Willoughby E, Zakaria M, Zvornicanin J, Balcer L, Plant GT. Diagnosis and classification of optic neuritis. Lancet Neurol. 2022 Dec;21(12):1120-1134. doi: 10.1016/S1474-4422(22)00200-9. Epub 2022 Sep 27.

Study record dates

Study Major Dates

• Study Start (Actual): January 6, 2025
• Primary Completion (Estimated): December 1, 2027
• Study Completion (Estimated): January 1, 2028

Study Registration Dates

• First Submitted: May 11, 2026
• First Submitted That Met QC Criteria: May 29, 2026
• First Posted (Actual): June 3, 2026

Study Record Updates

• Last Update Posted (Actual): June 3, 2026
• Last Update Submitted That Met QC Criteria: May 29, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Diagnostic accuracy; 2022 International Criteria for Optic Neuritis; Antibody-stratified adjunct; Aquaporin-4 immunoglobulin G; Myelin oligodendrocyte glycoprotein immunoglobulin G
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Eye Diseases; Sensation Disorders; Cranial Nerve Diseases; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Optic Nerve Diseases; Vision Disorders; Optic Neuritis
• Other Study ID Numbers: GX-ICON

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: De-identified participant-level data and a data dictionary will be made available to qualified researchers upon reasonable request after publication of the main diagnostic accuracy results, subject to ethics approval, institutional approval, and execution of a data use agreement.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No