It is often claimed that the human retina is poorly designed because light must travel through the nerves and blood vessels to reach the photoreceptor cells, which are located behind the eye’s wiring. Many specific reasons exist for this so-called backward placement of the photoreceptors. A major one is that it allows close association between the rods and cones and the pigment epithelium required to maintain the photoreceptors. It is also essential in both the development and the normal function of the retina. Both the rods and cones must physically interact with retinal pigment epithelial cells, which provide nutrients to the retina, recycle photopigments, and provide an opaque layer to absorb excess light.