Do Optic Canal Dimensions Measured on CT Influence the Degree of Papilloedema and Visual Dysfunction in Idiopathic Intracranial Hypertension?

A recent study found that increased optic canal area on magnetic resonance imaging was associated with worse papilloedema in idiopathic intracranial hypertension (IIH). We repeated this study using more accurate computerized tomography derived measurements. Optic canal dimensions were measured from 42 IIH patients and 24 controls.  These were compared with papilloedema grade.  There was no correlation between any of the optic canal measurements and papilloedema grade and no significant difference in optic canal measurements between patients and controls. Our results cast doubt on the existing literature regarding the association between optic canal size and the degree of papilloedema in IIH. CT delineates bony anatomy more accurately than MRI and our CT-derived optic canal measurements cast doubt on the existing literature regarding the association between optic canal size and the degree of Papilloedema in IIH.