SPLIT SPECTRUM: When a rainbow of white light enters the retina, funnel-shape Müller cells guide the beam through layers of cells and cellular processes to the photoreceptors (rods and cones). Müller cells function as optical fibers, directing and concentrating the yellow-green spectrum of light, to which many cone cells are tuned to respond maximally. Blue light seeps out of the Müller cells to activate rods. © KIMBERLY BATTISTA
The paper
A.M. Labin et al., “Müller cells separate between wavelengths to improve day vision with minimal effect upon night vision,” Nat Comm, 5:4319, 2014.
Our eyes, like those of most vertebrates, are layered counterintuitively, with light-receiving rod and cone cells at the back of the retina and neurons and glial cells stacked in front. Theoretically, this inverted structure—five layers deep—should result in blurry vision, given that light must propagate through all the reflecting and scattering cell layers before triggering the photoreceptors. Yet a normal eye forms images clearly.
A 2007 study led by Kristian Franze, now of the University of Cambridge, found that one kind of retinal glia, known as Müller cells, resolved the problem by functioning as optical fibers, channeling light to the ...
