A glial cell is a cell that supports and protects neurons. They serve to surround neurons and hold them in place, to supply nutrients and oxygen to neurons, to insulate one neuron from another, and to destroy pathogens and remove dead neurons.
One kind of retinal glial cell, the Müller cell, is of importance in transporting light from the surface of the retina to the photoreceptors. Vertebrate retinas have their photoreceptors at the back of the retina, with masses of neurons, blood vessels, and other cells between the photoreceptors and incoming photons. Müller cells act as fiberoptic light guides, allowing photons to pass through the retinal tissue relatively unimpeded.
In EyeWire, glial cells have a characteristic large, swoopy, irregular structure distinct from neural cells.
- Franze et al. (2007), Müller cells are living optical fibers in the vertebrate retina. Proc Natl Acad Sci U S A. 104(20):8287-8292.