They act, directly or indirectly, to transmit signals from the photoreceptors to the ganglion cells.

Bipolar cells are so-named as they have a central body from which two sets of processes arise.

There are roughly 10 distinct forms of cone bipolar cells, however, only one rod bipolar cell, due to the rod receptor arriving later in the evolutionary history than the cone receptor[attribution needed].

In photoreceptor cells, there is an abundance of cGMP in dark conditions, keeping cGMP-gated Na channels open and so, activating PDE diminishes the supply of cGMP, reducing the number of open Na channels and thus hyperpolarizing the photoreceptor cell, causing less glutamate to be released.

The amacrine cells also introduce lateral inhibition to the axon terminal, serving various visual functions including efficient signal transduction with high signal-to-noise ratio.