Can the angle between optic nerves indicate whether optic chiasm is prefixed, normofixed or postfixed? An anatomical study with radiologic and neurosurgical implications.

The INA is wider when OC is prefixed, intermediate when normofixed and narrowed when postfixed. This observation throws light on the possibility of using INA as a marker of RAPL of OC. As INA can be measured in axial MRI sections, it can be used in differentiation of the cases with prefixed OC from others during pre-operative work up for pituitary surgeries and to identify individuals 'at risk' during subfrontal approach for pituitary lesions.