The Acute Optic Neuritis Network (ACON): Study protocol of a non-interventional prospective multicenter study on diagnosis and treatment of acute optic neuritis

Susanna Asseyer*, Nasrin Asgari, Jeffrey Bennett, Omer Bialer, Yolanda Blanco, Francesca Bosello, Anna Camos-Carreras, Edgar Carnero Contentti, Sara Carta, John Chen, Claudia Chien, Mashina Chomba, Russell C. Dale, Josep Dalmau, Kristina Feldmann, Eoin P. Flanagan, Caroline Froment Tilikete, Carolina Garcia-Alfonso, Joachim Havla, Mark HellmannHo Jin Kim, Philipp Klyscz, Frank Konietschke, Chiara La Morgia, Marco Lana-Peixoto, Maria Isabel Leite, Netta Levin, Michael Levy, Sara Llufriu, Pablo Lopez, Itay Lotan, Alessandra Lugaresi, Romain Marignier, Sara Mariotto, Susan P. Mollan, Cassandra Ocampo, Frederike Cosima Oertel, Maja Olszewska, Jacqueline Palace, Lekha Pandit, José Luis Peralta Uribe, Sean Pittock, Sudarshini Ramanathan, Natthapon Rattanathamsakul, Albert Saiz, Sara Samadzadeh, Bernardo Sanchez-Dalmau, Deanna Saylor, Michael Scheel, Tanja Schmitz-Hübsch, Jemal Shifa, Sasitorn Siritho, Pia S. Sperber, Prem S. Subramanian, Alon Tiosano, Adi Vaknin-Dembinsky, Alvaro Jose Mejia Vergara, Adi Wilf-Yarkoni, Luis Alfonso Zarco, Hanna G. Zimmermann, Friedemann Paul, Hadas Stiebel-Kalish

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Optic neuritis (ON) often occurs at the presentation of multiple sclerosis (MS), neuromyelitis optica spectrum disorders (NMOSD), and myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD). The recommended treatment of high-dose corticosteroids for ON is based on a North American study population, which did not address treatment timing or antibody serostatus. The Acute Optic Neuritis Network (ACON) presents a global, prospective, observational study protocol primarily designed to investigate the effect of time to high-dose corticosteroid treatment on 6-month visual outcomes in ON. Patients presenting within 30 days of the inaugural ON will be enrolled. For the primary analysis, patients will subsequently be assigned into the MS-ON group, the aquapotin-4-IgG positive ON (AQP4-IgG+ON) group or the MOG-IgG positive ON (MOG-IgG+ON) group and then further sub-stratified according to the number of days from the onset of visual loss to high-dose corticosteroids (days-to-Rx). The primary outcome measure will be high-contrast best-corrected visual acuity (HC-BCVA) at 6 months. In addition, multimodal data will be collected in subjects with any ON (CIS-ON, MS-ON, AQP4-IgG+ON or MOG-IgG+ON, and seronegative non-MS-ON), excluding infectious and granulomatous ON. Secondary outcomes include low-contrast best-corrected visual acuity (LC-BCVA), optical coherence tomography (OCT), magnetic resonance imaging (MRI) measurements, serum and cerebrospinal fluid (CSF) biomarkers (AQP4-IgG and MOG-IgG levels, neurofilament, and glial fibrillary protein), and patient reported outcome measures (headache, visual function in daily routine, depression, and quality of life questionnaires) at presentation at 6-month and 12-month follow-up visits. Data will be collected from 28 academic hospitals from Africa, Asia, the Middle East, Europe, North America, South America, and Australia. Planned recruitment consists of 100 MS-ON, 50 AQP4-IgG+ON, and 50 MOG-IgG+ON. This prospective, multimodal data collection will assess the potential value of early high-dose corticosteroid treatment, investigate the interrelations between functional impairments and structural changes, and evaluate the diagnostic yield of laboratory biomarkers. This analysis has the ability to substantially improve treatment strategies and the accuracy of diagnostic stratification in acute demyelinating ON. Trial registration:, identifier: NCT05605951.

Original languageAmerican English
Article number1102353
JournalFrontiers in Neurology
StatePublished - 2023

Bibliographical note

Publisher Copyright:
Copyright © 2023 Asseyer, Asgari, Bennett, Bialer, Blanco, Bosello, Camos-Carreras, Carnero Contentti, Carta, Chen, Chien, Chomba, Dale, Dalmau, Feldmann, Flanagan, Froment Tilikete, Garcia-Alfonso, Havla, Hellmann, Kim, Klyscz, Konietschke, La Morgia, Lana-Peixoto, Leite, Levin, Levy, Llufriu, Lopez, Lotan, Lugaresi, Marignier, Mariotto, Mollan, Ocampo, Cosima Oertel, Olszewska, Palace, Pandit, Peralta Uribe, Pittock, Ramanathan, Rattanathamsakul, Saiz, Samadzadeh, Sanchez-Dalmau, Saylor, Scheel, Schmitz-Hübsch, Shifa, Siritho, Sperber, Subramanian, Tiosano, Vaknin-Dembinsky, Mejia Vergara, Wilf-Yarkoni, Zarco, Zimmermann, Paul and Stiebel-Kalish.


  • Aquaporin-4-IgG (AQP4-IgG)
  • MOG-IgG associated disorders (MOGAD)
  • clinically isolated syndrome (CIS)
  • multiple sclerosis (MS)
  • neuromyelitis optica spectrum disorders (NMOSD)
  • optic neuritis (ON)


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