Apply the new diagnosis and classification criteria for optic neuritis in a predominantly non-caucasian population in a resource-limited setting of an emergent country.

Optic neuritis presents a manifestation of different neurological and systemic disorders with distinct disease course. Objective diagnostic criteria are important for early recognition and should be applicable for distinct etiologies in different ethnic populations and geographical regions. New diagnostic criteria has been published by Petzold et al in 2022, based on clinical assessment and paraclinical tests establishing two different categories:  definite and possible optic neuritis; they also proposed an etiological classification for this condition. However, this new criteria have not yet been applied in a real-world population with great ethnic variability.

We analyzed 69 patients with confirmed optic neuritis. According to the new diagnostic criteria, 50 (72%) patients were classified as definite and 19 (28%) as possible optic neuritis. Based on the new etiological criteria, 30% patients had multiple sclerosis, 20% NMOSD (of this, 64% AQP4+), 4% MOGAD, 18% CRION, 20% SION and 5% infectious or systemic secondary neuritis.