retina-analysis-reference. Biologists who study vision are fascinated by the retina, the rear surface of the eye which collects light and transmits an 'image' to the brain. Through evolution, eyes have been exceptionally diverse across the animal kingdom, yielding a wide variety of shapes, sizes, colors, and chemical processes. For this reason, the eye is often used to understand how complex traits evolve with ecology, the interactions of the animal with its environment. A retinal ganglion cell map helps biologists visualize receptive cells across the rear surface of the vertebrate eye. This topographic map shows density in a way which highlights areas of higher visual performance, and this can be used to understand what regions of an animal's visual field are most clear-in-view. For a human, we only have one point on the eye where things are clear- that's why we can really only see a few words at a time while reading, for example. Some fish have multiple centers of high visual performance, more formally referred to as a peak of retinal acuity.