Tag Archives: eyesight

Just 3 minutes of red light therapy improves declining eyesight due to old age

Credit: Pixabay.

Researchers at University College London studied the effects of shining deep red light onto the eye, a form of therapy that previous studies hinted could improve declining eyesight. The new research confirms that a 3-minute session of longwave deep red light exposure per week significantly improved color contrast vision and the effects were long-lasting.

Deep red light, which has a wavelength of 670 nanometers, enhances the function of mitochondria, the energy factories found inside every animal and plant cell. When water encounters this wavelength, it absorbs its energy, which raises the frequency of vibration of the water molecules.

Since a type of molecular structure within the mitochondria, known as the ATP synthase pump, is bathed in water, the extra energy allows these pumps to rotate faster and release more energy into the biological cell.

Having more efficient mitochondria may improve a range of biological functions, but researchers at University College London led by Glen Jeffery only studied how deep red light and mitochondria relate to eyesight.

In a pilot study, they recruited 24 volunteers aged 37 to 70, who each were exposed to a weak deep red light pointed at their eyes for only 3 minutes. A few hours later, the participants’ color vision was assessed with a standard test where they had to detect letters on a similar-colored background.

Research suggests that mitochondria make the most ATP — energy-carrying molecules found in the cells of all living things — during the morning. So the scientists carried out the red light exposure both in the morning and the afternoon, with the latter acting as a control group.

Those who received the therapy in the morning (8 am to 9 am) scored 12% to 17% better on the color contrast test compared to their performance before the deep red light stimulation. One week later, their scores were still 10% better, suggesting the therapy provides long-lasting benefits. Those who received the red light therapy in the afternoon saw no significant change in their eyesight performance.

“We demonstrate that one single exposure to long wave deep red light in the morning can significantly improve declining vision, which is a major health and wellbeing issue, affecting millions of people globally,” Jeffery said.

“This simple intervention applied at the population level would significantly impact quality of life as people age and would likely result in reduced social costs that arise from problems associated with reduced vision.”

The human retina ages faster than other organs due to its high density of mitochondria, with a 70% ATP reduction over a person’s lifetime. The degeneration is particularly noticeable from around 40 years of age.

These findings suggest that red light treatment could prove highly useful when treating common conditions responsible for blindness, such as age-related macular degeneration and vision impairments caused by diabetes.

“Using a simple LED device once a week recharges the energy system that has declined in the retina cells, rather like re-charging a battery,” Professor Jeffery said.

“And morning exposure is absolutely key to achieving improvements in declining vision: as we have previously seen in flies, mitochondria have shifting work patterns and do not respond in the same way to light in the afternoon – this study confirms this.”

But since boosting mitochondria efficiency helps all the cells in your body do their jobs better, the same therapy may prove useful in treating a wider range of illnesses. Elsewhere, scientists are experimenting with deep red light therapy to treat brain injuries and Parkinson’s disease.

As a caveat, the sample size of the study was very low. What’s more, the magnitude of improvements in color vision varied significantly between individuals of similar age. As such, the results need to be interpreted with caution and more research with more participants is warranted.

The findings appeared in the journal Scientific Reports.

Acuity Kitchen Photo.

There are huge differences in how animals see the world — we’re among the crisp-eyed

Not all eyeballs are created equal.

Acuity Kitchen Photo.

Image credits E. Caves, N. Brandley, S. Johnsen , 2018, Trends in Ecology and Evolution.

If seeing is believing, humans probably believe a lot more than other animals, according to new research from Duke University. Our eyes perceive the world in much sharper detail than those of most other members of the animal kingdom, the results suggest.

To see or not to see

The researchers measured the visual sharpness of several species using a method called ‘cycles per degree’. Basically, what this method ascertains is how many pairs of parallel black and white lines an eye can distinguish in a single degree of vision. The human eye, the team writes, can resolve around 60 cycles per degree. Anything above 60 line pairs starts to look a blurry grey to us.

These measured visual acuity levels were then fed into software that transformed a reference image to give us a taste of how other animals see the world (the image above). Compared to most other organisms on the planet, our eyesight is actually crisp:

Eyesight sharpness.

Image credits Image credits E. Caves, N. Brandley, S. Johnsen , 2018, Trends in Ecology and Evolution.

The team writes that chimps and other primates see roughly as well as we do. That’s not very surprising, given that they’re our closest living relatives. There are a few species that can boast higher visual acuity than us the team notes that some birds of prey, such as the Australian wedge-tailed eagle with 140 cycles per degree, can see nearly two times more detail than we do. Given that they need to spot small prey from thousands of meters away, that’s not very surprising. Apart from these, however, we humans seem to have quite good eyesight.

Fish and most birds, the team reports, can only distinguish about 30 cycles per degree. Elephants can only see a paltry 10 — which is actually the level at which a human is declared legally blind.

The team also explored the implications of their findings. It’s easy to assume that every living thing sees the world roughly the same way as we do, but the results show there’s an incredible variation in visual acuity. They note the case of the cleaner shrimp, which “likely cannot resolve one another’s colour patterns, even from distances as close as 2 cm”. Then what’s the point of sporting bright colors and waving your antennae or your body around? For context, it looks like this:

The team believes that this behavior isn’t meant to communicate anything to other cleaner shrimp — it’s meant to signal fish: “both [the shrimps’] colour patterns and antennae are visible to fish viewers of various acuities from a distance of at least 10 cm,” they write.

“Thus, these distinctive colour patterns and antennae-whipping behaviors likely serve as signals directed at clients, despite the inability of cleaner shrimp themselves to distinguish them.”

They make a similar point about butterflies. Based on the team’s results, these animals probably can’t even distinguish each other’s patterns. Birds, however, can.

“The point is that researchers who study animal interactions shouldn’t assume that different species perceive detail the same way we do,” Caves concludes.

While I do find the findings fascinating, it’s important to note that animals may actually see better than their visual acuity alone suggests. The team’s research only focused on how their eyes work, but ‘seeing’ is mostly handled by the brain. It may very well be that these relatively dim-sighted species have neural systems in place to improve the final images they perceive.

For now, we simply don’t know. Judging from the amount of data each species’ eyes records, however, it may be that we are some of the sharpest-eyed animals out there.

The paper “Visual Acuity and the Evolution of Signals” has been published in the journal Cell.

Wearing glasses might really mean you’re smarter, new study finds

If you thought people who wear glasses are smarter, well, you might be right, according to a University of Edinburgh study.

Does he look intelligent? It’s because of the glasses, isn’t it?

It’s not every day that science gets the chance to address a frivolous stereotype, but here we are. In the largest study of its kind, Scottish researchers analyzed cognitive and genetic data from over 300,000 people aged between 16 and 102. Surprisingly, they found that people who were more intelligent, on average, were more likely to have genes which indicate they will wear glasses. This wasn’t the main focus of the study, but it was an interesting takeaway.

Overall intelligence has long been linked with many health traits, but these correlations are generally positive. Several studies have found that higher cognitive function can be linked to lower incidence of problems such as angina, lung cancer, and depression. More intelligent people generally tend to lead longer, healthier lives — but this is not necessarily a result of the intelligence itself, and is more likely to be a result of the lifestyles intelligent people generally choose to have.

“Some individuals have generally higher cognitive function than others,” researchers write in the study. “These individual differences are quite persistent across the life course from later childhood onwards. Individuals with higher measured general cognitive function tend to live longer and be less deprived.”

With eyesight, however, things seem to be quite different: the genetic correlations between general cognitive function and eyesight were in opposite directions. The team reports that they found that there was a 28% greater chance that people with higher cognitive levels would also need some form of vision correction. In other words, almost a third of people with higher cognitive levels will likely need glasses or contact lenses.

However, it’s important to note that poor eyesight and higher intelligence aren’t directly linked — no causation has been established between the two at all. Furthermore, assessing intelligence simply from DNA is challenging and somewhat subjective. Any missteps can lead people to fall into the unwanted trap of the so-called race science.

But despite the lack of scientific information, there’s plenty of evidence that wearing glasses, whether you need them or not, makes people think you are more intelligent, industrious, and reliable. It goes even further: glasses make people seem more harmless. As lawyer Harvey Slovis explained to New York magazine, glasses make people seem more incapable of a crime, creating a sort of “nerd defense.”

However, maybe it’s time we start looking beyond these prejudices, isn’t it?

Journal Reference: Gail Davies et al. Study of 300,486 individuals identifies 148 independent genetic loci influencing general cognitive function, Nature Communications(2018). DOI: 10.1038/s41467-018-04362-x

Doctors restore patient’s sight with stem cells, offering new hope for cure to blindness

Scientists have developed a specially engineered retinal patch to treat people with sudden, severe sight loss.

The macula lutea (an oval region at the center of the retina) is responsible for the central, high-resolution color vision that is possible in good light; when this kind of vision is impaired due to damage to the macula, the condition is called age-related macular degeneration (AMD or ARMD). Macula lutea means ‘yellow spot’ in Latin.

Picture of the back of the eye showing intermediate age-related macular degeneration.
Via Wikipedia

Douglas Waters, an 86-year-old from London, had lost his vision in July 2015 due to severe AMD. After a few months, Waters became part of a clinical trial developed by UC Santa Barbara researchers that used stem cell-derived ocular cells. He received his retinal implant at Moorfields Eye Hospital, a National Health Service (NHS) facility in London, England.

Before the surgery, Water’s sight was very poor, and he wasn’t able to see anything with his right eye. After the surgery, his vision improved so much that he could read the newspaper and help his wife in the garden.

The study, published in Nature Biotechnology, shows groundbreaking results. Researchers could safely and effective implant a specially engineered patch of retinal pigment epithelium cells derived from stem cells to treat people with sudden severe sight loss from wet AMD. This is the first time a completely engineered tissue has been successfully transplanted in this manner.

“This study represents real progress in regenerative medicine and opens the door on new treatment options for people with age-related macular degeneration,” said co-author Peter Coffey, a professor at UCSB’s Neuroscience Research Institute and co-director of the campus’s Center for Stem Cell Biology & Engineering.

Douglas Waters was struggling to see up close after developing severe macular degeneration, but 12 months on he is able to read a newspaper again

AMD usually affects people over the age of 50 and accounts for almost 50% of all visual impairment in the developed world. The condition disturbs central vision responsible for reading, leaving the surrounding eyesight normal. Wet AMD is caused by hemorrhage or liquid accumulation into the region of the macula, in the center of the retina. Wet AMD almost always starts as dry AMD. Researchers believe that this new technique will be the future cure for dry AMD.

Scientists wanted to see whether the diseased retinal cells could be replenished using the stem cell patch. They used a specially engineered surgical tool to insert the patch under the affected retina. The operation lasted almost two hours.

Besides Water, another patient, a 60-year-old woman who also suffered from wet AMD, underwent the surgery. The two patients were observed for one year and reported improvements to their vision. The results were incredible — the patients went from being almost blind to reading 60 to 80 words per minute with normal reading glasses.

“We hope this will lead to an affordable ‘off-the-shelf’ therapy that could be made available to NHS patients within the next five years,” said Coffey, who founded the London Project to Cure Blindness more than a decade ago.

 

 

Credit: Lars Andreas, Wikimedia Commons.

Revolutionary nanoparticle eye drops could make glasses obsolete

Credit: Lars Andreas, Wikimedia Commons.

Credit: Lars Andreas, Wikimedia Commons.

Israeli researchers have developed and tested “nanodrops” that, when used in conjunction with laser therapy, improve both short- and long-sightedness. In time, eyesight will return to its previous state but the researchers say the procedure can be repeated every one to two months, meaning your glasses could soon be outdated.

Since the 1960s, focused, carefully controlled lasers have been used to treat eye diseases. Lasers can be used to carefully reshape the cornea of the eye  — the transparent front part of the eye that covers the iris, pupil, and anterior chamber — to correct refractive errors that cause conditions like short-sightedness (myopia), long-sightedness (presbyopia), or blurred vision (astigmatism). Such procedures are increasingly common, and although there are some side effects (primarily some discomfort after the procedure and temporary visual changes as the cornea heals), they’re are considered safe.

Unlike conventional laser surgery, which removes a significant portion of the cornea, the technique developed by the Israeli researchers is far less invasive. First, the patient uses an app on his or her smartphone to measure their eye refraction. Then, a laser delicately etches patterns onto the corneal surface based on projections calculated by the app. The laser fires for no more than one second. The last step involves adding eye drops, which contain “special nanoparticles” that change the refraction index inside the shallow ablated patterns generated by the laser on the surface of the cornea.

Essentially, this multi-step process corrects whatever refractive index problems the user might have. The downside is that the cornea will gradually heal, reverting back to its initial configuration. This means that the eyedrops and laser have to be re-applied at regular intervals.

According to Dr. David Smadja, a research associate at the Shaare Zedek Medical Center in Jerusalem and Bar-Ilan University’s Institute of Nanotechnology and Advanced Materials (BINA), the groundbreaking procedure could one day replace multifocal lenses. The team has carried out ex-vivo experiments on pig eyes, which improved both short- and long-sightedness. The findings were reported at Shaare Zedek’s second annual research conference last month.

“Eyes drops filled with synthetic nanoparticules have shown promising potential for a revolutionary alternative non-invasive correction of refractive errors,” the authors reported in their study abstract, which analyzed the refractive errors of 10 pig eyes before and after the introduction of the nanodrops.”

Researchers expect to test the nanodrops on humans in clinical trials next year. The team is in the process of raising funds from Bar-Ilan University to make the nanodrops commercially available.

Just like humans, old bonobos suffer from long-sightedness

A new study has revealed that bonobos, some of humanity’s closest relatives, suffer from similar eye problems in old age. This would seem to indicate that long-sightedness isn’t a problem of modern lifestyle, but something completely different.

This photo shows Fuku (female: 17 years old) grooming Hoshi (female: 32 years old). She needs only 5 to 10 centimeters between her fingers to eyes to get pin-focus for grooming. Credit: Heungjin Ryu (CC BY-NC 4.0)

Long-sightedness affects the ability to see nearby objects. You may see very well distantly, but closer objects can be out of focus — especially when reading or using a computer. While it can affect people of all ages, people over 40 years old are especially vulnerable to it. The modern lifestyle is often blamed for this condition.

We spend too much time focusing our eyes on things which are close-by, we tire them working on computers and we don’t spend enough time in open spaces where our eyes can relax. But new studies have cast that theory into doubt by studying our closest relatives: chimps and bonobos. Previous studies have indicated that chimps also get long-sightedness in old age, and now, a new study has found the same thing in bonobos.

“One day, I was with another researcher and observed the oldest male bonobo Ten (TN) grooming Jeudi (JD),” Ryu recalls. “TN had to stretch his arm to groom JD, and only when he found something on JD’s body would he come close to remove it using his mouth. It was funny to see how he groomed.”

But while it may have been funny to them, it really is a struggle for bonobos and might have serious consequences for their survival. So scientists started studying exactly how their eyesight fares by using digital photographs to measure the grooming distance of 14 wild bonobos of various ages, ranging from 11 to 45 years old. The measurements showed that the distance increased exponentially with age — in other words, older bonobos groomed from further away, just like a human would hold the book a bit further away.

“The results we found were very surprising even for us,” Ryu says. “When I started to collect data, I did not expect that age could be such a strong predictor of long-sightedness.”

This also indicates that modern lifestyle isn’t to blame for the decline in our eyesight, or at least not entirely. There’s something else causing a decline in eyesight, a process deeply rooted in our evolutionary history.

Journal Reference: Heungjin Ryu, Kirsty E. Graham, Tetsuya Sakamaki, Takeshi Furuichi. Long-sightedness in old wild bonobos during grooming. Current Biology, November 2016 DOI: 10.1016/j.cub.2016.09.019 |

Blind woman uses eSight glasses to see her baby for the first time

What is it like to see for the first time? Most of us can’t even imagine that, because it happened when we were babies and we can’t recall our first visual memories. But Kathy Bleitz, a Canadian woman, certainly will – for the first time, she was able to see using a new technology called eSight. The first thing she saw was her baby.

Bleitz has been living with Stargardt disease, an inherited degenerative disease of the retina that causes progressive vision loss usually to the point of legal blindness. Legal blindness is a term used when people aren’t absolutely blind, but their eyesight is so bad that for all practical purpose, they can be considered blind (can’t really see people, can’t navigate by themselves, etc). For Bleitz, eyesight is extremely fuzzy – she can just see wavy shapes in broad daylight, and it gets even worse in dim light.

However, just after she gave birth, Bleitz got some very good news – she got access to the new eSight headset; eSight is a new patented technology – basically wearable electronic glasses that empower the legally blind to actually see. According to their website, eSight works for most people that are legally blind and is approved by the FDA. Inside the headset, there’s a high-definition camera, organic light-emitting diode (OLED) screen and a range of other technologies which capture images in real time and then transform and augment the image. It allows the user to adjust the contrast, brightness and color, just like with a television. It can also magnify the image up to 14 times.

“Interestingly, eSight’s many unique features – such as 14-times zoom, image contrast enhancement, reverse colour display, etc. – enable eSight users to actually see many things that normally-sighted people cannot see,” the developers write on their website.

The device shows great promise for most people suffering from blindness. In fact, most people we call blind aren’t fully blind – approximately 95 percent of legally blind individuals still have some eyesight and can be helped by eSight. A pair goes for quite a big price ($15,000) but developers have set up a donation system to help people acquire a pair. Tech Times reports that so far 140 people around North America are using them, and the company is now working on improving the design – making it smaller and easier to use.

Here’s another video of American airforce veteran, Mark Cornell, see for the first time in 20 years:

stereo-sue

Neurobiologist can see in 3-D after being stuck in 2-D for 48 years. [amazing brain adaption]

stereo-sue

Meet Susan Barry. She’s an accomplished neurobiologist and a professor of biological studies at Mount Holyoke College. For 48 years of her life, however, Susan was visually stuck in 2-D world. You see, she was born with her eye crossed and could only see in two dimensions. Our eyes each produce an image, and since they’re very close to another and in the same plane, unlike those of a horse for instance, the images are of an area more or less the same but from slightly different angles. The two separate images are then processed by the brain which combines the two by matching up similarities and adding up the slight differences between the two. The combined image is more than the sum of its parts. It is a three-dimensional stereo picture.

stereo vision drawingBack to Susan, though. Susan had a really tough time growing up, as you might imagine. Because of her condition, Susan could never focus both her eyes on the same point at the same time – the key to stereoscopic 3D vision – and was stuck in flat world. She had a lot of trouble reading, gaining visual perspective and living a normal life, bottom line. For many years, physicians believed that stereo vision can only be developed during a critical time in infancy. Susan believed this as well, after all, she was told this countless times by many different doctors.

As Susan got older, however, her vision worsen. She complained about her eyesight becoming “jittery” to her optometrist and began practicing a series of exercises designed to help stabilize her gaze. Along the way, however, she found that she could see in 3-D! Imagine her impression – she was 48! Better late than never, I suppose. The feat earned her the moniker “Stereo Sue,” coined by neurologist Oliver Sacks.

What “Stereo Sue” achieved, though, transcends her personal experiences because it shows the brain is capable of much greater adaption than we might credit it. “If we’re stuck in a rut, it’s because we think we’re stuck in a rut,” says Sue. “We can get better at everything.”  Her experience taught her that the brain could adapt – maybe even in some of the ways that we want it to adapt – even beyond the boundaries of the “critical period.”

Check out this 10 questions video with Susan, part of the “Secret Life of Scientists” show on PBS. Check out the bonus beneath the video.

Watch 10 Questions for Susan Barry on PBS. See more from Secret Life of Scientists.

BONUS!

Let’s have some fun. Below is a stereogram, which is basically an image which when visualized very closely will give the impression of depth. If you’ve never experienced a stereogram before, you’ll definitely rejoice. I remember being simply astonished at the sight when I gazed my first stereogram. At first glace, the image might not seem like much – a bunch of cows layered up in a seemingly chaotic order. Focus!

Read this to learn how to look at a stereogram first.

animal stereogram

How Do Humans Perceive Color — Color Deficiencies

While humans have the capability to interpret over 1,000,000 different colors, not all humans possess the genetics that will allow that kind of color fluctuations to be perceived. Inaccuracy in the genetic makeup can lead to deficiencies that alter how color should be perceived in optimal conditions.

Color Perception Outside the Eye
colour

The ability to perceive color begins when electromagnetic waves in the form of light reflect off an object. The reflection carries the visual color wavelength to the gadget, human or animal that is able
to perceive the color. In order for color differences to be perceived, the eye has to be capable of cracking the code with the right information sheet.

Normal Color Perception in the Human Eye

The eye perceives color when certain wavelengths of light are reflected off the object and enters the eye through the lens. The message is then sent to the retina where photoreceptors in the shape of cones or rods interpret the message. Color vision is interpreted by the cones.

Within the cones are three kinds of photosensitive receptors that interpret different wavelengths based on the makeup. Normally each cone is responsible for interpreting a different range of wavelengths: long, medium or small, or red, green, or blue sensitive wavelengths. The LMS title is more accurate because the capabilities of each cone overlap. While the cones responsibilities do overlap, a cone not interpreting its range of responsibly could lead to an inability to perceive or distinguish certain colors.

Color Perception Deficiencies: Who is affected and Why
eye

In a study conducted by DM Hunt in 1991, he found that 8 percent of men and .4 percent of women were affected by some variation of color deficiency. It becomes clear with this study that men and women are not equally likely to be unable to perceive the full spectrum of colors available with the three-cone photopigment types.

The ability to perceive color is a “sex-linked genetic trait.” Like many other diseases and genetic anomalies, color perception comes down to the genetics passed down from the mother or father through the x chromosomes. Women who have two x chromosomes have two chances to receive the DNA strands that allow for the full spectrum of color vision. Men only receive one chromosome from the mother, so if the mother’s family has a history of color perception deficiencies, he will have a higher chance of color blindness. If the mother is colorblind, the son will be as well.

Types of Color Deficiencies

There are multiple types of color deficiencies that people may possess.

The first type is the inability to distinguish between certain colors due to a missing photopigment type. Within this category there are three types that can be missing.

• Protanopia: Missing L-cone photopigment leads to an inability to distinguish between red and green hues.
• Deutonopia: Missing M-cone photopigment leads to an inability to distinguish between red and green hues of a higher luminous sensitivity.
• Tritanopia: Missing S-cone photopigment leads to an inability to distinguish between yellow and
blue.

Another type of color deficiency is called anomalous trichomacy. People affected by Protanomaly, Deuteranomoly, or Tritanomaly have a reduced ability to distinguish between the hues effected because
of either a weak sensitivity in the L, M, or S cone or a “contamination of photopigments.” That is to say that some larger or smaller wavelength sensitivity is present where they should not be.

• Protanomaly: L-cone photopigment weakness or M or S cone photopigment where there should be L cones photopigment leads to a harder time distinguishing between red and green hues.
• Deuteranomoly: M-cone photopigment weakness or L cone photopigment where there should be M cones photopigment leads to a harder time distinguishing between red and green hues of a higher luminous sensitivity.
• Tritanomaly: S-cone photopigment weakness or M or L cone photopigment where there should be S cones photopigment leads to a harder time distinguishing between yellow and blue hues.

Thinking about how genetics are combined to form new life seems to be the activity of scientists, introduction biology classes, and people looking for potential sperm donors. We hardly ever make up a questionnaire listing all the undesirable genetic treats that we might pass on to our offspring. And when it comes down to it, the inability to distinguish color is a minor issue; a genetic hiccup that causes some inconvenience in certain social situations. Until a potential cure is found, if one is even needed, the best thing that people with a color perception deficiency is to know about it and come up with ways to compensate for it. The only other alternative at this time is eugenics—and that has the potential of going south fast.

 

Points within the face (green circles) where, on average, each of 50 participants first looked at when trying to identify faces of famous people. White circle corresponds to the average across all participants. Background is an averaged face across 120 celebrity faces. (c) UCSB

Right below the eyes is the best place to get the look of a person

Eye contact plays a very important role in human interactions, however a recent research study made by psychologists at UC Santa Barbara found that looking below the eyes is the best place to get the feel of what a person is up to. Besides, apparently most of us are already hard-wired to fix our initial gaze to this point, albeit for an extremely short period and unconsciously.

“It’s pretty fast, it’s effortless –– we’re not really aware of what we’re doing,” said Miguel Eckstein, professor of psychology in the Department of Psychological & Brain Sciences

Points within the face (green circles) where, on average, each of 50 participants first looked at when trying to identify faces of famous people. White circle corresponds to the average across all participants. Background is an averaged face across 120 celebrity faces. (c) UCSB

Points within the face (green circles) where, on average, each of 50 participants first looked at when trying to identify faces of famous people. White circle corresponds to the average across all participants. Background is an averaged face across 120 celebrity faces. (c) UCSB

Miguel Eckstein and Matt Peterson used high-speed eye tracking cameras, more than 100 photos of faces and a sophisticated algorithm to pinpoint the first place participants looked at when fixing their gaze towards a person, in order to assess their  identity, gender, and emotional state.

“For the majority of people, the first place we look at is somewhere in the middle, just below the eyes,” Eckstein said.

The whole initial, involuntary glance lasts a mere 250 millisecond, yet despite this and the relatively featureless point of focus, during these highly important initial moments our brain performs incredibly complex computations that plan eye movement in advance to ensure the best information gathering possible, as well as assess whether its time to run, fight or entertain.

“When you look at a scene, or at a person’s face, you’re not just using information right in front of you,” said Peterson.

The eyes are the windows to one’s soul, but what lies beneath it?

You might have noticed whenever you look at something, anything, the center of your point of view appears more refined and clearer than its surroundings, which offers less spatial detail. The high resolution areas are picked up by a region of the eye known as the fovea, which is a slight depression in the retina.

When sitting next to a person at a conversational distance,  the fovea can read the whole person’s face in great detail and catch even the most subtle gestures. More detail spatial information relating to face features like the nose, mouth and eyes is readily available. Despite this, however, when study participants were asks to asses the identity, gender and emotions of an individual based on a photograph of his forehead or mouth alone, for instance, they did not perform as well as they did when looking close to the eyes.

These empirical data were correlated with the output of a sophisticated computer algorithm that mimics the varying spatial detail of human processing across the visual field and integrates all information to make decisions, allowing the researchers to predict what would be the best place within the faces to look for each of these perceptual tasks. The common denominator derived from both the computer model and actual human participant data is that looking below the eyes is the optimal place to look, say the scientists, because it allows one to read information from as many features of the face as possible.

“What the visual system is adept at doing is taking all those pieces of information from your face and combining them in a statistical manner to make a judgment about whatever task you’re doing,” said Eckstein.

This doesn’t seem to be a general rule for all humans, though. Previous research, say the scientists involved with the paper published in the journal PNAS, has found that t East Asians, for instance, tend look lower on the face when identifying a person’s face. Next  Peterson and Eckstein are looking to refine their algorithm in order to provide insight into conditions like schizophrenia and autism, which are associated with uncommon gaze patterns, or prosopagnosia – an inability to recognize someone by his or her face.

source: UCSB

 

One of the GRIN lenses.

New artificial lenses mimic the natural qualities of the eye

Modern sight correction medical procedures often involve surgery where an artificial lens is implanted. The patient’s sight is significantly improved, however the quality of vision is far from that experienced with a healthy pair of eyes. That’s because current artificial lenses function more or less like those from a camera, a bit more advanced of course. The eye is a lot more complicated, on the other hand. Recently a team of researchers have successfully constructed a lens that is closer to the human eye than any of its counterparts.

One of the GRIN lenses.

One of the GRIN lenses.

During high school optics, textbooks and teachers would often use the human eye as an allegory for a natural light bending lens. Then they would compare it to a camera, when discussing refraction – the bending of light in a particular direction when traveling through a new medium. Fact of the matter is, a camera’s lens is only comprised of only one or a few other layers. As light passes through the lens, it’s bent only at the surface of the lens, and then exits in a straight line. This is why artificial lens implants, while still improving sight considerably, aren’t that effective.

The eye, however, bends light continuously. To create an artificial lens with features closer to the natural qualities of the eye, scientists at Case Western University, the Rose-Hulman Institute of Technology, the U.S. Naval Research Laboratory, and Case Western spin-off company PolymerPlus made a single lens from hundreds of thousands of layered and laminated nanoscale polymer films. The technology is known as GRIN (gradient refractive index optics).

Each of these thousands of stacked films has slight different optical properties, which causes light to be incrementally bent by multiple degrees as it passes through the lens.

“As light passes from the front of the human eye lens to the back, light rays are refracted by varying degrees,” said Michael Ponting, president of PolymerPlus. “It’s a very efficient means of controlling the pathway of light without relying on complicated optics, and one that we attempted to mimic.”

Lenses currently employed by today’s technology and used to treat sight impairment conditions, like cataract, lack the ability to incrementally change the refraction of light, and thus fail to come close to the performances of the human eye.

“A copy of the human eye lens is a first step toward demonstrating the capabilities, eventual biocompatible and possibly deformable material systems necessary to improve the current technology used in optical implants,” says Ponting.

Since the technology also enables optical systems with fewer components, GRIN could be used not only as medical implants, but also in consumer and military products.

“Prototype and small batch fabrication facilities exist, and we’re working toward selecting early adoption applications for nanolayered GRIN technology in commercial devices,” says Ponting.

Findings were published in the journal Optics Express.The animation below describes the M-GRIN manufacturing process used to make the new lenses:

source

Eating tons of ice cream won't help your brain get any bigger, though. Sorry!

Northern people have bigger eyes and brains

Eating tons of ice cream won't help your brain get any bigger, though. Sorry!

Eating tons of ice cream won't help your brain get any bigger, though. Sorry!

A new Oxford University study shows how people living further away from the equator have bigger eyes and brains than those living closer to it. This is to cope with the harsh colder climate, scientists say.

Anthropologists come to this conclusion after examining 55 skulls, dating from the 1800s, representing 12 different populations from around the globe. By measuring eye sockets and brain volumes, the researchers were able to make a comparison based on the latitude in which the sockets were collected.

As such people living further north, like native-Scandinavian dwellers have bigger eyes and brains than, for say, those living in Micronesia, located just north of the equator, who actually had the smallest score. This doesn’t necessarily mean vikings are smarter, though. Scientists say these modifications came as a result of the colder climate, which forced these populace to grow a larger portion of the brain devoted to vision, due to low light conditions caused by cloudy skies and long winters in northern territories.

Professor Robin Dunbar, Director of the Institute of Cognitive and Evolutionary Anthropology at Oxford University, said in a press release:

“Humans have only lived at high latitudes in Europe and Asia for a few tens of thousands of years, yet they seem to have adapted their visual systems surprisingly rapidly to the cloudy skies, dull weather and long winters we experience at these latitudes.”

Related, scientists have long saw a correlation between eye size and increased/improved nocturnal activity. It’s well known that birds with somewhat over-sized eyes are the first to sing at down, or that certain primates with big eyes are a lot more comfortable during the night than their cousins.

The research was published in the journal Biology Letters.

Box jellyfish study reveals amazing eyesight

The box jellyfish (commonly known as the sea wasp) is not only the most venomous creature in the world, but it also holds a few other major surprises. They may seem like rather simple creatures at a first glance, but researchers are now convinced they are nothing like this; as a matter of fact, they have no less than 24 eyes, of four different types, which makes them among the creatures with the most interesting eyesight in the world. The sea wasp uses these eyes to navigate the waters it lives in.

“It is a surprise that a jellyfish — an animal normally considered to be lacking both brain and advanced behavior — is able to perform visually guided navigation, which is not a trivial behavioral task,” said Anders Garm of the University of Copenhagen. “This shows that the behavioral abilities of simple animals, like jellyfish, may be underestimated.

Scientists have long known that the sea wasp has a unique array of eyes, but they didn’t even suspect just how unique and special it was; it was known that they could rely on vision to respond to light, avoid obstacles, and control their rate of swimmin, but box jellyfish live in seas with a multitude of obstacles, so this is no major surprise.

The species they investigated, Tripedalia cystophora lives in a special environment, in the swamps formed by the Caribbean mangrove roots, where it always stays close to the surface, and they are never found in the open, where they risk starvation.

“We have shown that the box jellyfish can use vision to navigate in their habitat, and we now want to understand how their simple nervous system supports such advanced behaviors,” Garm concluded.

Artificial Cornea Saves Eyesight

 

cornea

With the growing number of people with eye problems it is harder and harder to find answers to problems raised;  some cases are so bad that there is no other sollution and a cornea transplant is needed. Every year, in Germany alone, around 7000 people wait for a new cornea to save their eyesight. The bad thing is that there are not nearly that many around.

In an EU project, researchers have developed an artificial cornea which is to be clinically tested in early 2008. A man who has a damaged or worse cornea because of a congenital malformation, hereditary disease or corrosion is at risk of going blind, and often the only solution is to implant a donor cornea. Many attempts have therefore been made at producing artificial corneas, so far with little success. This is due to the conflicting requirements imposed; it has to grow firmly but the cells have to deposit themselves at the center of the cornea, as this impairs the patient’s vision.

The research scientists at the Fraunhofer Institute for Applied Polymer Research (IAP) in Potsdam and the Department of Ophthalmology at the University Hospital of Regensburg have worked with other colleagues in the EU-funded CORNEA project and they have found a solution.

“Our artificial corneas are based on a commercially available polymer which absorbs no water and allows no cells to grow on it,” says IAP project manager Dr. Joachim Storsberg. “Once our partner Dr. Schmidt Intraokularlinsen GmbH has suitably shaped the polymers, we selectively coat the implants: We lay masks on them and apply a special protein to the edge of the cornea, which the cells of the natural cornea can latch onto. In this way, the cornea implant can firmly connect with the natural part of the cornea, while the center remains free of cells and therefore clear.”

They have tested the corneas in the laboratory and found that their cells graft very well at the edge. This means that the optical center of the implant manages to stay clear. The first implants have already been tested in rabbits’ eyes and the results are very good so humans are probably going to benefit from this.