Now that's an eye-popping picture.
For the first time, a breakthrough technology reveals in action in the living eye those amazingly tiny light-sensing rods that, along with cones, are responsible for vision.
"It's a quantum leap -- literally," Alfredo Dubra of the University of Rochester told FoxNews.com.
For decades, scientists have been able to examine these tiny structures by taking biopsies of the eye. But examining them in living eyes opens up a whole new world for reducing eye disease, potentially letting researchers diagnose the diminutive structures and study the specific effect of drugs on them.
"It really could have a massive impact in the care of eye disease," Dubra said. "But it's really the beginning of an important period. What we need to learn now is how to interpret the picture."
Cones, the larger round structures seen at the right side of the picture, show red, green and blue and create the perception of color. Rods, their far smaller cousin structures, don't distinguish colors. There are approximately 120 million of them in the eye, each measuring just 2 microns in diameter (a micron is 1/1,000 of a millimeter).
What's even more amazing: Dubra's breakthrough was "embarrassingly simple, and relied on well-known equations and concepts," he said.
It uses the same photography process astronomers use to peer into the most distant parts of the heavens.
In astronomy, adaptive optics (AO) correct for the blurring effect of Earth's atmosphere, removing the "twinkling" from starlight and rendering cosmic objects as very sharp points of light. To do so, it relies on a deformable mirror to create the exact but opposite distortion.
Just as light passing through the atmosphere becomes bent, so too does light passing through the front part of the eye. This distortion is inconsequential on the scale of human vision, but poses a significant barrier in the microscopic realm of medical imaging.
By folding the spherical mirrors that act as lenses in the instrument into a 3D structure, the image quality of the retina was improved sufficiently to capture the historic photo.
"While therapies are only emerging, the ability to see the cells you are trying to rescue represents a critical first step in the process of restoring sight," said Dubra, who led the team of researchers from Rochester, Marquette University, and the Medical College of Wisconsin (MCW), Milwaukee.
"It's impossible to overemphasize how important early detection is to eye disease," he added.
"This is a really exciting breakthrough," agreed Steve Burns, a professor in the School of Optometry at Indiana University, who is not involved in the Biomedical Optics Express research. "Since many of the eye diseases most amenable to intervention affect the rods, this should become a major tool for determining what treatments work best for those disorders."
The study was published in the latest issue of Biomedical Optics Express.