epvydjpu

Fiber optic light pipes in the retina do much more than simple

first_img Explore further (Phys.org) —Having the photoreceptors at the back of the retina is not a design constraint, it is a design feature. The idea that the vertebrate eye, like a traditional front-illuminated camera, might have been improved somehow if it had only been able to orient its wiring behind the photoreceptor layer, like a cephalopod, is folly. Indeed in simply engineered systems, like CMOS or CCD image sensors, a back-illuminated design manufactured by flipping the silicon wafer and thinning it so that light hits the photocathode without having to navigate the wiring layer can improve photon capture across a wide wavelength band. But real eyes are much more crafty than that. Journal information: Nature Communications This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. More information: Müller cells separate between wavelengths to improve day vision with minimal effect upon night vision, Nature Communications 5, Article number: 4319 DOI: 10.1038/ncomms5319AbstractVision starts with the absorption of light by the retinal photoreceptors—cones and rods. However, due to the ‘inverted’ structure of the retina, the incident light must propagate through reflecting and scattering cellular layers before reaching the photoreceptors. It has been recently suggested that Müller cells function as optical fibres in the retina, transferring light illuminating the retinal surface onto the cone photoreceptors. Here we show that Müller cells are wavelength-dependent wave-guides, concentrating the green-red part of the visible spectrum onto cones and allowing the blue-purple part to leak onto nearby rods. This phenomenon is observed in the isolated retina and explained by a computational model, for the guinea pig and the human parafoveal retina. Therefore, light propagation by Müller cells through the retina can be considered as an integral part of the first step in the visual process, increasing photon absorption by cones while minimally affecting rod-mediated vision. Researchers use human stem cells to create light-sensitive retina in a dishlast_img

Leave a Reply

Your email address will not be published. Required fields are marked *