It is a small depression in the retina, at the center of the so-called luteal macula. It occupies one total area of slightly greater than 1 mm square.In all mammals, the fovea is the area of the retina where the light rays are focused and is especially trained for the acute and detailed vision.The area, also known as fovea centralis, does not have poles but only cones, responsible for the perception of colors. The conos-M for the green area and the conos-L for the red area of visible light are arranged in the fovea centralis in a regular mosaic. Depending on the species, they are or not here present a few conos-K, responsible for the perception of the blue area of the visible light. More internal region, the foveola ( measured in humans of approx. 0.33 mm. diameter ) It is possible to find only particularly slender cones of the M-type and L.Un object the eye focuses on is always fixed in such a way that its reflection is exactly located right in the fovea centralis. The absence of stick ( cell ) and the consequent inability to perceive fine under bad lighting conditions structures, is particularly difficult, for example, reading a text in the penumbra.The fovea centralis is a convergence of 1: 1, i.e. after every receiver there is a ganglion cell. Namely, the receivers are connected 1: 1, so the fovea is the best resolution, i.e. the greater visual sharpness.