Toyota 2012 Prius C Owner's Manual page 114

1-4. Adjustable components (seats, mirrors, steering wheel)
Anti-glare inside rear view mirror
The rear view mirror's position can be adjusted to enable sufficient
confirmation of the rear view in accordance with the driver's seating
posture.
Adjusting the height of rear view mirror
Anti-glare function
Reflected light from the headlights of vehicles behind can be reduced
by operating the lever.
94
Adjust the height of the rear view
mirror by moving it up and down.
Normal position
Anti-glare position