A rearview assembly is disclosed for use in a vehicle for providing a rearward view from the vehicle. In one example, the rearview assembly includes at least one substrate having a partially transmissive coating and a light sensor proximate the at least one substrate. The rearview assembly further includes a secondary optic. The secondary optic has a first surface facing outward toward the at least one substrate and a second surface facing inward toward the light sensor. Vertical flutes extend uniformly along the first surface and horizontal flutes extend uniformly along the second surface. The secondary optic is configured to control a field of view of the light sensor.