Nanoparticles and Near Infrared Vision

Last month an article was published in Cell describing how researchers had injected the retinas of mice with nanoparticles that attached to retinal photoreceptor cells and changed near-infrared light (IR) to green light the animals could see in the dark. Like a mouse version of night vision goggles without the goggles.

To see if the treated mice could actually see in the IR range (700 nanometers to 1 millimeter), they checked the pupils of the injected mice and noted that the test animals' eyes constricted when shown 900 nm light, while the controls (not treated) mice did not.  

Then, researchers gave the mice a choice of two boxes: one that was completely dark and one illuminated by near-infrared light. Control mice spent time in both boxes, but mice with nanoparticle treated retinas chose the dark box, suggesting that they could see the near-IR light and preferred the dark. 

This research has tons of applications. All of which are fascinating. I plan to keep an eye on developments in mammalian night vision. Who knows? Maybe someday everyone will have excellent night vision and no one will stub a toe in the dark. Go science!

Scallops' Eyes are Amazing

It's known that scallops have dozens, sometimes hundreds, of eyes. In fact, their retinal design provides an elegant example of nature's engineering. However, these structures are difficult to study in a lab due to drying and other physical deterioration. 

So, Lia Addadi at the Weizmann Institute of Science and her team, including Benjamin Palmer and Gavin Taylor  decided to try a cryo-scanning electron microscope and the rapid freezing of samples to keep delicate and important structures intact. 

With this method, they discovered that scallops' eyes each have a segmented mirror that grows individually. They are made of square, flat, guanine crystals (a millionth of a meter wide) that link together into a grid. 

Stacked groups of grids (20-30) have liquid filling the spaces between them. The crystals and separating spaces are 74 and 86 billionths of a meter thick which works well at reflecting blue-green light in the ocean environment.

The group also noticed that the mirror crystal segments are not inactive, but seem to grow inside the cells of the scallop’s eye, filling them up. Then, they join together to form a uniform mosaic layer. 

So now that we know how scallops' eyes develop, the next research question is whether they all provide images individually or combine information into a single complex image? I can't wait to find out. Go science!

Speedy Bee Vision

The early bird gets the worm could be changed to the quick bee gets the pollen. Recent research has discovered that the photoreceptors in bees' eyes can detect black and white images about 4-5x faster than humans. They can see color 3-4x faster than humans. 

What good is visual speed? Scientists believe vision is important in bees' ability to find flowers and pollen. The high-speed vision might help bees keep track of color in flickering light (e.g., when flying quickly through bushes).

"The scene for the bee would be flickering with different amounts of light and shade, and the color view is potentially changing, from a flower reflecting more light to less light," said study author Peter Skorupski, a researcher at Queen Mary, University of London, in England. Fast color vision could help bees accurately perceive color during flight.

So the next time you bend to sniff a flower and encounter a bee, realize he probably saw you first. Relax and let him go about his pollen collecting business. Go science!

Snow Blindness

Looking out upon the white snowy landscape resulting from winter storm Euclid, I got to thinking about snow blindness. Can the average person get snow blindness? What is it? Is it permanent? 


Snow blindness, or sunburn of the eye's surface, happens at high altitudes where incoming ultraviolet rays reflect off snow to burn the corneas of unprotected eyes. Like sunburn, the problem isn't noticed until hours later when eyes are teary or bloodshot. With severe exposures, eyes feel gritty and may swell shut. Fortunately, corneas usually heal in 12 - 48 hours and painful snow blindness rarely causes permanent eye damage. 

Bottom line = wear winter eye protection (especially in high altitudes) and enjoy the snow! It's my favorite time of the year.