Dec. 22, 2011 Humans see color thanks to cone cells, specialized
light-sensing neurons located in the retina along the inner
surface of the eyeball. The actual light-sensing section of
these cells is called the outer segment, which is made up of a
series of stacked discs, each about 30 nanometers (billionths of
a meter) thick. This appendage goes through daily changes in
length. Scientists believe that a better understanding of how
and why the outer segment grows and shrinks will help medical
researchers identify potential retinal problems. But the methods
usually used to image the living human eye are not sensitive
enough to measure these miniscule changes. Now, vision
scientists at Indiana University in Bloomington have come up
with a novel way to make the measurements in a living human
retina by using information hidden within a commonly used
technique called optical coherence tomography (OCT). They
discuss their results in the Optical Society's (OSA) open-access
journal Biomedical Optics Express. To make