1. Human eye has 125 million rod cells and 7 million cone cells. These rods and cones are not evenly distributed.

2. The yellow spot has only cones. As the distance increases from yellow spot towards ciliary body the number of rods increases and number of cones decreases.

3. The blind spot has no rods and no cones because the optic nerve arises from it. Since, there are no photoreceptors thus, there is no perception of the image.