Abstract
Unilateral proptosis can be a sign of a potential threat to vision or life. Here, we report a case of unilateral proptosis with bilateral asymmetrical compressive optic neuropathy. A 36-year-old Malaysian indigenous female presented with painless right-eye proptosis associated with progressive blurring of vision for the past month. She had painless progressive left-eye vision loss for eight years. There was marked right-eye proptosis with partial ophthalmoplegia. The optic nerve functions were significantly reduced in the left eye with a positive relative afferent pupillary defect (RAPD). Humphry perimetry showed a right superior nasal field defect. Brain imaging showed two different masses located at the suprasellar and right greater wing of the sphenoid extraaxial lesion likely representing a meningioma. She was diagnosed with bilateral compressive optic neuropathy secondary to intracranial mass and was referred to the neurosurgical team for further intervention. This case highlights that painless proptosis with early vision loss of the fellow eye may be the early presenting symptom of meningioma, without any symptoms of raised intracranial pressure. Brain imaging is warranted to rule out any intracranial pathology if a visual field defect is present.