Features and associations of optic neuritis in the Middle East: A cross-sectional study

Background

Differences exist in the clinical profile of optic neuritis (ON) among various populations. The present study outlines the features of optic neuritis and its associations in Middle Eastern population.

Methods

In a single tertiary care neuro-ophthalmology clinic, we reviewed charts between 2016 and 2021, to identify patients with optic neuritis. Patients with at least one single episode of ON, and a follow up for at least 6 months were only included. Patients from countries outside the Middle East were not eligible. We performed a sub-analysis using data from the clinic, laboratory, and radiological findings to classify patients with optic neuritis into 4 groups: idiopathic ON, multiple sclerosis associated optic neuritis (MS-ON), neuromyelitis optica spectrum disorder associated optic neuritis (NMOSD-ON), and myelin oligodendrocyte glycoprotein associated disease optic neuritis (MOGAD-ON).

Results

77 patients met the criteria for inclusion in the study. Approximately, two thirds of the patients (64%, 95% CI [0.52–0.74]) had MS-ON, 17 patients had idiopathic ON (22.6%, 95% CI [0.13–0.33]), 6 patients were diagnosed with NMOSD-ON (8%, 95% CI [0.02–0.16]), and 4 patients had MOG-ON (5.3%, 95% CI [0.01–0.13]). More than half of patients with idiopathic ON were found to have clinically isolated syndrome (CIS) and thus to be at high risk of developing MS. Among all patients enrolled in the study, the mean age was 29.8 ± 9.53 years. Patients with MS-ON and MOG-ON were relatively younger compared to patients from other groups (P = 0.0005). There was a female preponderance among all groups except MOG-ON, where 80% were males (P = 0.11). The pre- and post-treatment logMAR visual acuity (VA) tended to be worse in NMOSD-ON than other categories (P = 0.062). Optic disc swelling was more common among patients with MOGAD-ON, and least common in patients with NMOSD (100% vs 0%, P = 0.001). 5 patients presented with simultaneous bilateral involvement, and all but one had NMOSD-ON. 29% of patients had recurrence during the time of the study with significant difference in prevalence across groups. There was no difference in the involvement of the chiasm, or the retro-chiasmal pathways across groups.

Conclusions

Our study demonstrates that multiple sclerosis (MS) is the predominant CNS demyelinating disease associated with optic neuritis (ON) in the Middle Eastern population, mirroring trends observed in Western populations. The clinical and radiological features of each subtype showed no significant divergence compared to findings from studies conducted in other regions globally. These insights contribute to a deeper understanding of ON's clinical spectrum and aid in refining diagnostic and management strategies in the Middle Eastern population.