In the eye, the inner layer known as the retina plays a crucial role in the process of phototransduction, which is the conversion of light energy into an electrochemical response, ultimately sending visual information to the brain. The retina consists of two primary layers: the pigmented layer and the neural layer. The pigmented layer, a single cell layer at the back of the retina, supports and protects photoreceptors while absorbing excess light. It is essential for the functioning of the eye, as it provides nutrients from the underlying choroid, which supplies blood to the retina.

The neural layer is where the actual phototransduction occurs, containing photoreceptors and neurons. There are two types of photoreceptors: rods and cones. Rods are sensitive to low light levels and are responsible for night vision, while cones are responsible for color vision and function best in bright light. When light enters the eye, it first passes through the neural layer before reaching the photoreceptors at the back. This arrangement may seem counterintuitive, as the wiring of the retina is positioned in front of the photoreceptors, but it is a result of evolutionary processes.

Once light is absorbed by the photoreceptors, it generates graded potentials, which are then transmitted to bipolar cells. These bipolar cells act as intermediaries, relaying the signal to ganglion cells, which generate action potentials. The axons of ganglion cells form the optic nerve, carrying visual information to the brain. Additionally, amacrine and horizontal cells are present in the retina, facilitating lateral communication and initial visual processing, although their specific functions are less critical for basic understanding.

Overall, the retina's structure and function exemplify a complex biological system that efficiently processes visual information, despite its seemingly unconventional design. Understanding the roles of the various cell types within the retina is essential for grasping how we perceive light and images.