muller cells
neurophilosophy | August 27, 2009THE retina has an inverted structure which seems ill-suited to its function: the rod and cone cells, which are sensitive to light, and which convert light energy into electrical impulses, point backwards and are located at the back of the retina, so that light entering the eye has to pass through several layers of irregularly organized cells before it reaches them. The retina also contains nerve fibres which are positioned perpendicular to the path of light entering the eye, and many of the structures in the upper cell layers have a diameter similar to that of the wavelength of visible light…
edyong | February 8, 2009This is the first of eight posts on evolutionary research to celebrate Darwin's bicentennial.
If you were a designer tasked with creating a machine for collecting and processing light, the last thing you would come up with is the human eye. Darwin marvelled at the eye as an "organ of extreme perfection", but in this, he was wrong. Aside from the many illusions that can fool them, our eyes have a major structural flaw. In humans and other back-boned animals, the light-sensing cells of the eye - the "photoreceptors" lie at the back of the retina.
In front of these sensors lie several layers…