Retinal mosaic is the name given to the distribution of any particular type of

neuron A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural net ...

across any particular layer in the

retina The retina (; or retinas) is the innermost, photosensitivity, light-sensitive layer of tissue (biology), tissue of the eye of most vertebrates and some Mollusca, molluscs. The optics of the eye create a focus (optics), focused two-dimensional ...

. Typically such distributions are somewhat regular; it is thought that this is so that each part of the retina is served by each type of neuron in processing visual information. The regularity of retinal mosaics can be quantitatively studied by modelling the mosaic as a spatial point pattern. This is done by treating each cell as a single point and using spatial statistics such as the Effective Radius, Packing Factor and Regularity Index. Using

adaptive optics Adaptive optics (AO) is a technique of precisely deforming a mirror in order to compensate for light distortion. It is used in Astronomy, astronomical telescopes and laser communication systems to remove the effects of Astronomical seeing, atmo ...

, it is nowadays possible to image the photoreceptor mosaic (i.e. the distribution of rods and cones) in living humans, enabling the detailed study of photoreceptor density and arrangement across the retina.PLoS One. 2018 Jan 16;13(1):e0191141. doi: 10.1371/journal.pone.0191141. eCollection 2018. In the fovea (where photoreceptor density is highest) the spacing between adjacent receptors is about 6-8 micrometer. This corresponds to an

angular resolution Angular resolution describes the ability of any image-forming device such as an Optical telescope, optical or radio telescope, a microscope, a camera, or an Human eye, eye, to distinguish small details of an object, thereby making it a major det ...

of approximately 0.5

arc minute A minute of arc, arcminute (abbreviated as arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of a degree. Since one degree is of a turn, or complete rotation, one arcminute is of a tu ...

, effectively the upper limit of human

visual acuity Visual acuity (VA) commonly refers to the clarity of visual perception, vision, but technically rates an animal's ability to recognize small details with precision. Visual acuity depends on optical and neural factors. Optical factors of the eye ...

References

Visual system Color vision {{neuroscience-stub