highest in the region where axons of retinal ganglion cells form the optic nerve leaving the eye.

 lowest in the retinal regions where receptive fields of retinal ganglion cells are smallest.

highest in retinal regions where only rods are present.

highest, in both daylight and at night, in the region where cones are maximally concentrated.

 highest in retinal regions where functioning retinal ganglion cells have the smallest receptive fields.