This type of polarized vision improves visual contrast and can help an animal catch its prey more easily, said Nicholas Roberts of Manchester University’s Photon Science Institute and its School of Physics and Astronomy. His research is the first direct experimental evidence of a polarization detection mechanism in any normal vertebrate eye. The research team believes that discovering how single cells work as polarization detectors may lead to new developments in man-made microscopic detection or information display technologies.

“Vision is the primary sense of many animals, and the way they see their world is of fundamental importance to understanding aspects of their behavior,” Roberts said. “Numerous animals have amazing visual abilities, which allow them to see the world in very different ways.”

One such ability is polarization vision. “Just as fishermen wear Polaroid sunglasses to help improve contrast, many different animals – including fish – have evolved to do the very same thing without the need of sunglasses. It is a surprisingly common ability throughout the animal kingdom,” he said.

For the study, Roberts used “laser tweezers” to manipulate the cells in three dimensions. This meant that for the first time, the absorption of single photoreceptors could be studied in the same orientation in which they are in the retina. He stressed that the team has so far only investigated one of the three-color channels known to play a role in polarization vision.

“This is just the first step in understanding the full mechanism that allows vertebrates to see polarized light, but we see these initial results as extremely encouraging,” he said. “We are now examining in much greater detail the underlying biochemical properties that make only some photoreceptor cells polarization detectors.”

The real challenge, he said, is building an integrated picture of vertebrate vision. “We are aiming to discover how both the biochemical and biophysical aspects of visual cell function link to the way polarization information is first analyzed, processed and then relayed to the brain.”

The paper, “A Mechanism of Polarized Light Sensitivity in Cone Photoreceptors of the Goldfish Carassius auratus,” is in the November 2007 Biophysics Journal (volume 93).
For more information, visit: www.eps.manchester.ac.uk

Source: Fish Don’t Need Sunglasses

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Clueless is not something I’ve ever been in regard to the wearing of sun glasses. A contact lens wearer since the age of 14, my ophthalmologist was ahead of her time when educating me on the benefits of protecting eyes from the sun’s ultraviolet A and B rays. UVA and UVB are not just threats to skin but also pose a danger to eyes and thus healthy vision. Savvy sunglass sense is common sense applied to optimal eye health. Awareness is key to purchasing optimal eye protection.

Always remembering to protect your eyes whenever outside. This includes riding in a car; working in the garden; even in the winter time when shoveling snow. Anytime you are exposed to ultraviolet light your eyes need protection.

Seek out polycarbonate lenses. These are shatter resistant. All lens material should be tagged UVA/UVB protective; if they’re not, don’t buy ‘em (this includes children’s character sunglasses).

Polarized lenses reduce glare. Wraparounds are practical for day-long light exposure. Try on several pairs to get a feel for fit and visual field sight; sunglasses should never compromise or hinder vision.

Lens colors fluctuate with current fashion trends. Darker does not mean “better” and some color-changing lenses (photochromic) often don’t correct to meet light swings. If possible, try glasses in diverse light(s).

Over the counter shades routinely tend to be optically impaired. Expect some distortion and/or magnification effect even from pricey designer glasses as they’re not ophthalmologically correct.

Just wear ‘em! Ultraviolet rays can contribute to cataract formation; hasten macular degeneration. You’re never too young or old to “skip” eye protection.

Source: Associated Content

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Many people also love sunglasses for their allure. Sunglasses create an aura of mystery, flirtatiousness, toughness or coolness. Individuals may pay quite a bit of money for a pair that they love. Designer sunglasses can range anywhere from $60 up to over $1000 depending on the designer and all of the bells and whistles that make a pair special. Some pairs themselves have been touted as “eye jewelry”- because of the added little extras within them.

But some just don’t have the budget for high-end sunglasses. An item like that may just not be a necessity. But everyone needs a pair of sunglasses. What are they to do? That’s where discount sunglasses come in handy.

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