However , if the eyes are asymmetrically affected , i.e. one eye 's optic nerve is more damaged than the other , it will produce an important sign called an afferent pupillary defect .
If both eyes are affected by PION , the pupils may look symmetrical .
If the eyes are asymmetrically affected , i.e. one eye 's optic nerve is more damaged than the other , it will produce an important sign called an afferent pupillary defect .
If both eyes are affected by PION , the pupils may look symmetrical .