Atypical presentation of MOGAD-associated optic neuritis with premacular haemorrhage.

A man in his 30s presented with sudden vision loss in the right eye and diminished vision in the left eye accompanied by headache. Clinical findings included bilateral disc oedema, reduced visual acuity in both eyes (right eye>left eye), dense premacular haemorrhage in the right eye and impaired colour vision. Blood tests were positive for serum myelin oligodendrocyte glycoprotein (MOG) antibodies, confirming MOG-associated optic neuritis (ON). Early intravenous methylprednisolone administration led to partial recovery; however, the right eye required pars plana vitrectomy for visual improvement. This case highlights that atypical ON associated with MOG antibodies can present with vascular complications such as premacular haemorrhage, likely due to inflammation-induced venous congestion. Prompt recognition, thorough evaluation and early intervention are key to optimising the visual outcomes in such atypical presentations.