Answer:
Left Eye
Step-by-step explanation:
Pay attention to the "LEFT optic nerve." If it didn't specify which, it'd be denoted as the contralateral visual field, however, it DOES specify a side, so thus, Christy is blind in her left eye.
I'm sure her insurance will cover her montly eyepatch allowances, don't worry about Christy. She's fiiiiiiiiiiiiiiine.