Vision and Eye News
Could a 3D Printer Make a Human Eye?
April 2015 A design company named MHOX says yes. In fact, the company estimates its EYE 3D bioprinted sight augmentation products, called Eye Heal, Eye Enhance and Eye Advance, will be on the market in 2027.
MHOX says that it's possible to print organic body parts that function as well as or even better than our natural ones, and that includes the eye. After all, 3D printers have already created prosthetics and bone replacements.
The eyes would be bioprinted with a needle that drops cells that then clump together. Various bio-inks would be used to re-create differentiation of various eye tissues that have different functions.
MHOX imagines that a wi-fi gland and a filter gland could improve and record images your eye sees, so you could share your visual experiences with other people.
The company also projects that eyesight could be improved up to 15/10 far sharper vision than our current standard of 20/20 with a "hyper-retina." Eye functionality could be improved as well, to treat eye injuries and even cure eye diseases.
The envisioned process includes a surgical procedure to install the Deck, "the technology that actually connects the eye to the brain," according to MHOX's website, after the natural eye is removed. Then users could interchange their own augmented eyes without surgery.
Okay, we're getting into very weird territory here: People would have their eyes removed and then could actually replace their own augmented eyes? Hmm. And it is hard to imagine that a 3D printed clump of cells could function as well as or better than our naturally grown peepers.
But the concept is fascinating, so keep an eye on 3D printing, which may become an integral part of our medical care in just a few years from now.
Image: Caitlin McNeill
The Big Dress Debate
February 2015 If you were on social media recently, you likely heard about the picture of a dress that is sparking a heated debate.
Initially posted on Tumblr by 21-year-old Caitlin McNeil, the dress is perceived by some people to be white and gold, while others see it as black and blue. The divide in opinion has inspired a viral debate across the web.
Because the processing of colors largely depends on light, our brains develop a "color constancy" system to ensure that colors are perceived the same way, even when there's a varying amount of light. For example, color constancy ensures that a red crayon looks red in the sunlight and looks red when it's in a dark shadow. It is alleged that because of this, the surroundings of an object influence our perception of color.
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This brings us back to the dress debate. It is largely believed that the differing opinions on color are based on our brain's assumptions of the surroundings. What kind of lighting is hitting the dress?
Some interpret the dress in a blue-lit room, perhaps near a window with a blue sky on the other side. If that's the case, the brain would "remove" the blue hue from the image, because it's perceived as a shadow.
Others see the dress as being photographed in artificial yellow light. Their brain then sees the gold as light catching the texture of the black lace. They do not filter out the blue, allowing them to see it as a blue and black dress.
The truth is that individual perception of color can often vary from person to person. This particular image seems to be ambiguous enough that our brains have to do a lot of interpreting. N.B.
New Smartphone Technology for Measuring Refractive Errors
February 2015 Smart Vision Labs has developed a portable device, SVOne, which attaches to smartphones to measure refractive errors in eyes. This low-cost, easy-to-use autorefractor is especially helpful in parts of the world where eyeglasses are hard to come by because of a shortage of equipment and trained professionals.
Video: Verizon Wireless
The device has a wavefront sensor that measures refractive errors such as nearsightedness and farsightedness.
The attachment takes a few snapshots of the eye, then uses a smartphone to analyze the images and produce digital refraction data.
The SVOne is pocket-sized and has a battery that can last over 50 hours while doing continuous refractions. It has been field-tested in Haiti and Guatemala and found to be very effective in non-clinical conditions.
Hopefully the new technology will help the millions of people across the globe who don't have access to eye care to at least get a pair of glasses if needed. N.B.
Getting Enough Sleep? Your Rapid Eye Movements
May Be Saying, "Get to Bed Right Now!"
January 2015 A team of scientists has found that rapid eye movements could provide an objective way to measure fatigue in people who work long hours.
Also called saccadic movements, these mostly voluntary eye movements help us fix our eyes on objects that attract our attention.
In the study, the scientists evaluated the performance of doctors from the Traumatology Service at St. Joseph's Hospital and Medical Centre in Phoenix, before and after their "call-day," which is a 24-hour shift during which the doctors don't sleep.
After these long shifts, the speed of their saccadic movements was reduced as they felt more fatigued.
Fortunately, when the physicians performed simulated laparoscopic tests after their shifts, their performance was not affected significantly by their fatigue. It's probable that fatigue is not the sole contributor to errors committed on the job. Still, measuring eye movements might be a good way to determine whether physicians, truck drivers, subway operators, ship captains and other vital workers are not getting enough sleep.
An article about the study appeared in Annals of Surgery.
Smoking Causes Eye Damage Similar to That Found in Glaucoma
December 2014 It appears cigarette smoking damages the eye in a way that resembles the early stages of glaucoma, according to a new study.
Researchers in Turkey evaluated the effect of smoking on the retinal nerve fiber layer (RNFL), which collects visual impulses from photoreceptors (rods and cones) and ganglion cells in the retina and transmits these impulses to the optic nerve.
A total of 88 adults between the ages of 20 and 50 participated in the study: 44 had smoked at least one pack of cigarettes a day for more than 10 years, and 44 did not smoke. All were in good health, and there were no significant differences in age, sex distribution, refractive errors or eye pressure between the two groups.
Examinations of their retinas revealed the mean thickness of the retinal nerve fiber layer of the smokers was significantly thinner than that of the non-smokers. Thinning of the RNFL also is associated with eye diseases such as glaucoma and retinitis pigmentosa, causing blind spots in the visual field, loss of peripheral vision and even blindness.
Artist With Rare Condition Sees Millions of Colors
November 2014 Concetta Antico, an impressionist artist, has been in the headlines lately for a rare eye condition that allows her to see more colors than the average person.
Tetrachromacy is a condition where the eyes have four different types of photoreceptor cone cells instead of three, allowing a person to see a broader spectrum of colors. This condition is very rare among humans and is believed to be much more common in females than males.
Antico, who lives in California, claims to be able to process up to 100 million colors, based on recent genotyping. (The average person can see about one million colors.) But because there is so little research done on tetrachromats, it's unknown whether humans possess the right neural pathways to process all the wavelengths a fourth cone absorbs. Researchers at the University of California, Irvine, have been studying Antico and hope to unlock more information about her rare eye condition.
Antico believes that painting in an impressionist style gives her the freedom to show how she perceives color. Visit her website to see her interesting paintings.
Study Reveals Visual Conditions of Healthy 10-Year-Old Children
August 2014 Recent studies have found the prevalence of myopia is increasing worldwide, including in the United States where approximately 42 percent of young adults are now nearsighted. With this in mind, it's useful to understand when the progression of nearsightedness begins.
A new study from Sweden suggests that less than 10 percent of healthy 10-year-olds are myopic.
Researchers at Uppsala University evaluated the vision and eye conditions of 217 healthy, full-term 10-year-old children. In addition to determining refractive error and visual acuity via a cycloplegic eye exam, additional tests were performed to detect the presence of strabismus and other binocular vision disorders.
Results revealed 17 children (7.8 percent) were nearsighted, eight children (3.6 percent) had at least 2.0 diopters (D) of farsightedness and nine (4.1 percent) had at least 1.0 D of astigmatism. Two children (0.9 percent) had anisometropia of at least 1.0 D, and seven children (3.2 percent) had manifest strabismus. Three children (1.4 percent) had below-normal contrast sensitivity, and five children who did not have strabismus had reduced stereopsis.
Among all children in the study, 178 (82 percent) had better than 20/20 visual acuity on a standard eye chart, and none were visually impaired (best corrected visual acuity worse than 20/80).
The study authors concluded the results of this study can be used as a control when examining children of similar ages with various eye conditions or other health issues.
A full report of the study was published online by the journal Acta Ophthalmology in July.
Amblyz Eyewear: A New Alternative to Patching That Kids May Like Better
July 2014 A company called XPAND has received approval from the FDA for electronic eyewear that can occlude one eye in amblyopic children ages 3 to 10.
Amblyz glasses are an alternative to patching and atropine drops that may be more acceptable to kids. Although they look like prescription eyewear from the outside, they contain an electronic shutter controlled by a microchip within the frame.
Since kids with a lazy eye usually need vision correction as well as a patch, the Amblyz eyewear is also designed to serve as prescription glasses.
If you are interested in Amblyz glasses for your child, ask your eye care provider about them. Please click here for close-up photos.
Braille Phone Debuts
June 2014 A year ago we reported on a Braille smartphone that was being developed in India. Now a London-based company called OwnFone has launched a simple phone with customizable Braille buttons.
All of OwnFone's credit card-sized phones are partially 3D printed, and when they order, purchasers can customize them online with the various colors, patterns and buttons available.
The company's other scaled-down phones are designed for limited uses, such as for a child or senior. The new Braille-buttoned version is based on this keep-it-simple concept, with either two or four pre-programmed Braille buttons to provide instant communication with friends, family or caregivers.
An emergency services button which must be pressed three times for activation is also included.
The Braille phone is available only in the United Kingdom for now, at a retail price of 60 pounds sterling.
You Are Being Watched: How Eye Contact Sells Kids' Cereal
May 2014 A study of product placement in grocery store cereal aisles reveals a creepy fact: the faces on cereal boxes are designed to make eye contact with you and your kids.
You've probably noticed that adult cereals are usually placed on higher shelves, while children's cereals are lower down. But Cornell University researchers found there's more to cereal marketing than that. In fact, the characters and people depicted on the boxes tend to look straight ahead at adults and downward at children. In essence, the packaging is designed to make eye contact with the people who are most likely to want the food inside.
Does the strategy work? When the researchers asked 63 people to view (randomly) either a Trix box with the bunny looking at the viewer or one with the bunny looking down, they found that brand trust and the feeling of connection to the brand were significantly higher when the bunny looked at the viewer.
So how do you protect your child from the come-hither glances of the Lucky Charms leprechaun? You could place him in the grocery cart seat so he doesn't see the kids' cereal box characters trying to catch his eye. Or just avoid the cereal aisle when shopping with your kids.
A report of the study appeared in the Journal of Environment and Behavior. (Image: Musicus, Tal & Wansink - Environment & Behavior, 2014)
Mind Your Beeswax
April 2014 They're at it again: Those crazy kids are finding new and stupid uses for perfectly good products.
Read our lips: This stuff is not for eyelids!
This time it's that tried-and-true beeswax lip balm made by Burt's Bees, which some high school and college kids reportedly have been applying to their eyelids. They've even come up with a catchy name for it "beezin'."
Some hopefully not science majors maintain that beezin' helps keep them awake so they can study. Others say it makes them feel drunk or high.
Few would dispute that Burt's Bees lip balm is a mighty fine product. But there's a really great reason you shouldn't put it on your eyelids: It contains peppermint oil and possibly some other ingredients that, if they come into contact with your eyes, will cause inflammation, burning and redness.
According to eye doctors, it's very important not to apply any cosmetic in or near the eyes that hasn't been formulated for that purpose, because the possibility of sight-threatening eye damage is very real.
Alcohol Free Weekend April 4-6: Do It for Your Eyes
April 2014 Did you know that drinking too much alcohol can affect your eyes? It can cause eye dryness, and it is a suspected cause of eyelid twitching.
Alcohol increases your risk for cataract development. And it can trigger short-term double vision and the inflammation that causes ocular rosacea.
April is Alcohol Awareness Month and a good time to take a look at how alcohol may be affecting your eyes and your overall health.
On April 4-6 the National Council on Alcoholism and Drug Dependence is inviting everyone to participate in Alcohol Free Weekend three days of abstinence that may help you reduce your consumption of alcohol and improve your health.
Give it a try!
Video: What Is the Resolution of the Human Eye?
March 2014 When buying a camera, TV, computer monitor, laptop or other digital device, we usually want to know the resolution.
Whether it's expressed in pixel dimensions or total megapixels, the number gives us some idea of what to expect in screen or print quality.
But have you ever wondered what the resolution is of the human eye? Is it better or worse than what we can experience on a digital screen? And how does the brain affect the quality of what we see with our eyes?
How Does Alcohol Really Affect Your Vision?
January 2014 Researchers in Australia have found that drinking the legal limit of alcohol greatly affects the ability to adjust vision for brightness and contrast by 30 percent.
The study, conducted at Western University's Faculty of Social Science, used the Hermann Grid to understand how alcohol affects the perception of contrast.
The Hermann Grid is a grid of black squares on a white background. Ghost-like dark spots appear at the intersections of the grid but are not actually there.
According to researchers, it's the way our visual system processes contrast or brightness differences that creates this illusion.
The researchers were able to show that the apparent contrast of the illusory spots in the grid is reduced by 30 percent at a blood alcohol level around the legal driving limit. This means that making distinctions between different objects based on lightness and darkness becomes more difficult when we drink alcohol.
Gene Therapy Holds Promise for Treating Eye Disease
January 2014 People suffering from a rare degenerative eye disease might finally have hopes for improved vision though gene therapy.
Choroideremia is caused by defects in a single gene on the X chromosome that leads to blindness and affects one in 50,000 people, mainly boys. Many start losing night vision by age 10 and become legally blind in their 40s. Because of the defective gene, light-sensitive cells in the retina slowly stop working and then die.
In an early-stage clinical trial, University of Oxford researchers used a deactivated virus to safely transport billions of healthy, lab-made versions of the gene into the retina. That appeared to restore the function of light-sensitive cells.
The trial began with six patients. Two still had excellent visual acuity, which was measured by reading lines of letters on a sight chart. Two other patients had good acuity, and two had reduced acuity. Six months after the operation, the two patients with reduced acuity showed improved vision, being able to read two and four more lines on the sight chart. The others could see better in dim light. The gains were sustained over several months of follow-up.
The experiment marks one of the first times that gene therapy has targeted the main light-sensing cells in the retina. And it offers a possible blueprint for treating far more common causes of blindness that affect the same cells, such as retinitis pigmentosa and age-related macular degeneration.
Blue Handheld Laser Devices Can Cause Serious Eye Injuries
December 2013 Exposure for even fractions of a second to high-powered blue handheld laser devices can cause serious eye injuries, according to a study released online in the journal Ophthalmology. The researchers have concluded that the wide availability of these devices, which are often marketed as toys, could lead to an epidemic of ocular injuries.
The natural protective mechanisms of the eye such as the blink reflex are ineffective against these lasers, and severe retinal damage may occur, even after momentary exposure. Studies have also shown that blue lasers are more likely to cause retinal injury compared with green or red lasers.
Blue laser devices often resemble laser pointers that have lower wattages. But blue laser devices actually have an output power of up to 1,200 milliwatts.
Potential eye injuries include macular holes, hemorrhages and macular puckering, whereby cells proliferate on the surface of the retina, causing visual impairment.
Visualization Can Affect Pupil Size
December 2013 Simply imagining scenes such as a sunny day or a night sky can cause your pupils to change size, a new study finds.
Pupils automatically dilate (get bigger) or contract (get smaller) in response to the amount of light entering the eye. The study, conducted by the University of Oslo in Norway, shows that visualizing dark or bright scenes affects people's pupils as if they were actually seeing the images.
In one experiment, participants looked at a screen with triangles of different levels of brightness. When later asked to imagine those triangles, the participants' pupils varied in size according to each triangle's brightness. When they imagined brighter triangles, their pupils were smaller, and when they imagined darker triangles, their pupils were larger.
Pupils also changed diameter when study participants imagined a sunny sky, a dark room, or a face in the sun versus a face in the shade, according to the study published online in the journal Psychological Science. The research may potentially enable scientists to probe the mental experiences of animals, babies and even people with severe neurological disorders, the study authors suggested.
Improved Vision May Have Helped Red Sox Win the Series?
November 2013 In the wake of the Red Sox winning the World Series in Game 6, there is speculation that the fourth-inning home run by shortstop Stephen Drew may have been due in part to his brand-new contact lenses.
After all, he reportedly wasn't wearing vision correction before then, and his post-season hitting record had been abysmal (though his defensive play remained strong).
We don't know how bad Drew's uncorrected vision is, but we do know that batting a ball that's hurtling toward you at 90+ mph is not easy even with excellent visual acuity and contrast sensitivity.
The beards didn't win the title for Boston. It was the players' talent and physical abilities including their ability to see the ball that ultimately helped them prevail this year. Which is why all athletes need to take care of their vision and get regular eye exams.
Simple Blood or Urine Test May Identify Retinitis Pigmentosa
October 2013 Researchers at Bascom Palmer Eye Institute have discovered a key marker in blood and urine that can identify people who carry genetic mutations in a gene responsible for retinitis pigmentosa, a blinding disease that affects about one in 4,000 people in the United States.
The first mutation in this gene, named DHDDS, was identified in 2011 by scientists at the University of Miami Miller School of Medicine. Mutations in this gene are more common in persons of Ashkenazi Jewish heritage than in the general population.
Retinitis pigmentosa is a group of inherited eye diseases that cause progressive vision loss and blindness due to degeneration of the retina, the layer of light-sensitive tissue at the back of the eye.
Take the #EyePledge in Honor of World Sight Day and You Can Generate Donations to an Eye Charity!
October 2013 World Sight Day is October 10, and it's a great opportunity for you to make an appointment for an eye exam.
Vistakon, a division of Johnson & Johnson Vision Care, is asking everyone to take an "eye selfie" photo and post it online in one of two ways:
- Either post it through the "Donate a Photo" app by Johnson & Johnson with #EyePledge;
- Or share it on social media sites (Facebook, Twitter, Instagram), using #EyePledge.
When you post your photo, you should also promise to get your eyes tested.
If you use the "Donate a Photo" app to upload your photo on behalf of the charity organization Sight for Kids, Johnson & Johnson will donate $1 (up to $30,000) to the charity. Sight for Kids has provided free vision screenings to more than 17 million children in Asia Pacific since 2002.
The "Donate a Photo" app is available from the App Store and Google Play. You can post up to one photo per day via the app.
Research Supports Extended Patching for Childhood Amblyopia
October 2013 Increasing patching from two hours to six hours a day effectively treats persistent amblyopia, according to a Pediatric Eye Disease Investigators Group (PEDIG) study published in the journal Ophthalmology.
Image: Krafty Eye Patches
Patching is the standard treatment for amblyopia, according to the National Eye Institute, which funded the research. Eye care practitioners often increase the daily duration if children stop making progress.
Researchers enrolled 169 children between ages 3 and 8 with persistent amblyopia in the study. One treatment group continued with two hours of daily patching, and another increased daily patching to six hours.
After 10 weeks, children in the six-hour patching group could see an average of 1.2 additional lines on an eye chart with the affected eye. Children in the two-hour patching group improved on average only 0.5 lines. Perhaps even more compelling, 40 percent of children in the six-hour group saw two or more lines of improvement.
The report proposes an evidence-based, staged approach for treating amblyopia:
- The first stage is wearing eyeglasses, to correct vision as much as possible.
- Patching for two hours a day or using eye drops or lens filters that blur vision in the better eye is recommended if amblyopia persists after 10 weeks of wearing glasses.
- If amblyopia persists after 10 weeks with two-hour daily patching, PEDIG recommends children patch for six hours per day.
Once children reach maximum visual acuity, the report recommends monitoring them for recurrence.
Will Your Doctor Be Using a Smart Phone App to Diagnose Eye Disease?
September 2013 Researchers from Massachusetts Eye and Ear have found an alternative way for eye doctors to capture high-resolution images of the retina: a smart phone app.
Commercial fundus (retinal) cameras can be costly for eye care practices, especially those in developing countries, and the cameras' large size limits their portability.
By combining the technologies of Apple's iPhone 4 or 5, a smart phone video camera app called Filmic Pro and a 20 diopter lens, the researchers captured excellent retinal images at a significantly lower cost with these mobile devices.
"This technique has been extremely helpful for us in the emergency department setting, in-patient consultations and during examinations under anesthesia, as it provides a cheaper and portable option for high-quality fundus-image acquisition," said senior author Shizuo Mukai, MD, Mass. Eye and Ear retina specialist and Harvard Medical School associate professor of ophthalmology.
The research team expects the quality of these images to continue to improve as smart phone technology advances. They predict that more eye doctors will use smart phone technology as an easy, inexpensive way to document eye diseases.
A full report of this study was published online this month in Journal of Ophthalmology.
Electrical Stimulation of Brain Helps Adults With Amblyopia
July 2013 A growing body of evidence reveals that the human brain has greater neuroplasticity than previously thought when it comes to the treatment of amblyopia.
Researchers in China tested the hypothesis that transcranial direct-current stimulation of the visual cortex would enhance the effects of dichoptic videogame-based treatment. (In a dichoptic video display, each eye is presented a separate and independent array of objects. Vision therapy of this type has been shown to aid in amblyopia treatment.)
Sixteen young adults with amblyopia (mean age 22.1 years) participated in the study. Compared with videogame therapy alone, the combined treatment led to greater improvements in binocular functioning.
According to the study authors, the electrical brain stimulation in the combined treatments appears to improve effectiveness by reducing the inhibition of input from the amblyopic eye to the visual cortex by cortical interneurons. They recommended additional studies be performed to evaluate this new approach for adults with amblyopia.
The study report appeared this month in Neurotherapeutics.
Can Tetris Correct Lazy Eye in Adults?
When a child has amblyopia, the usual treatment is to patch one eye. Adults, however, don't normally respond to this type of therapy.
For older amblyopes, vision therapy techniques including special computer programs can encourage neural changes that result in better vision. Recently, scientists tested the video game Tetris as a fun tool in this kind of therapy.
The idea is that the rapidly changing scene in a game like Tetris forces both eyes to work together and heightens plasticity levels in the visual cortex the area of the brain that processes visual input.
In the Tetris study, 18 adults were tested for two weeks, with half wearing goggles that covered one eye. The group that played the game with both eyes unobstructed showed significant vision improvement.
A report of the study appeared in the April 2013 issue of Current Biology.
New Eye Movement Test Could Reduce Need for Costly Stroke Testing
April 2013 Often people who have severe dizziness are tested for stroke. In our healthcare system, stroke work-ups are very expensive, so the ability to rule out stroke by other means could save time and money.
Measuring eye movements with a special goggle, to determine whether dizziness is due to stroke.
That's why researchers at Johns Hopkins Medicine tested an electronic device that measures eye movements in people with dizziness or vertigo, to see if it could determine whether the symptoms are due to stroke or a more benign condition.
Three eye movement tests are used to check the balance system in possible stroke victims. One, called the horizontal head impulse test, is the best stroke predictor, so the researchers performed it with a video-oculography machine to detect very small eye movements.
Patients wore a special goggle that contained a webcam and an accelerometer in the frame. A laptop was connected to the webcam, software determined eye position based on the webcam input and the accelerometer measured how fast the patient's head moved.
Six of the 12 patients in the study were diagnosed with stroke, while the other six had benign conditions. All the diagnoses were confirmed later with MRI.
A report of the study appeared in the April issue of the journal Stroke.
Visual Evaluation Needed After Any Traumatic Brain Injury, Says Study
February 2013 Researchers have found that as many as 65 percent of people who sustain traumatic brain injury (TBI) develop associated vision problems. The vision problems occurred whether the trauma was blast-related, such as TBI sustained by Iraq and Afghanistan War veterans from explosions in combat, or non-blast-related, such as TBI sustained by civilians in auto accidents, falls or other trauma.
TBI-related vision problems included light sensitivity, eye movement dysfunction, focusing problems and eye teaming problems. Related symptoms included eye strain and difficulty reading.
What's striking is that despite these vision problems, most of the patients had normal visual acuity. The researchers suggested that anyone with TBI should have a comprehensive vision examination, regardless of the cause or severity of their injury.
The study report appeared in the February issue of Optometry & Vision Science.
Did Scarlet Fever Cause Mary Ingalls' Blindness?
February 2013 Probably not, says a study that appeared in the February issue of Pediatrics.
Laura Ingalls Wilder wrote of her sister Mary's vision loss in the Little House on the Prairie series of books about her childhood. She wrote that it had resulted from a bout of scarlet fever.
Using newspaper reports, school registries and Wilder's memories, the researchers concluded that Mary's blindness was likely caused by viral meningoencephalitis. Her symptoms, including facial nerve inflammation that caused temporary paralysis of the side of her face, strongly suggest meningoencephalitis.
The disesase also could have caused inflammation of the optic nerve, which would lead to vision loss.
The researchers speculated that the editors of Wilder's books may have decided to name scarlet fever as the cause, since most people were familiar with the disease and knew how deadly it could be to children.
Light Exposure During Pregnancy Important to
Good Infant Vision Development
January 2013 Did you know that normal eye development requires light to reach an infant even while in the womb?
This finding reported in this month's Nature is based on studies of fetal mice. The researchers discovered that a light-response pathway controls the number of neurons in the retina.
In mice, this pathway must be activated during late gestation, about 16 days into the pregnancy.
The light-response pathway keeps the blood vessels forming in the retina from becoming too numerous and causing potentially blinding retinopathy of prematurity.
Are People With Brown Eyes More Trustworthy?
January 2013 In a study of 238 university students in Prague, participants were asked to rate photos of 40 female and 40 male students for perceived trustworthiness. The photos of brown-eyed people received higher ratings than those of blue-eyed people.
Who looks more trustworthy to you?
But eye color was probably not the determining factor, concluded the researchers. Apparently, there is a correlation between brown eye color and certain face shapes.
When the researchers showed the students photos with brown eyes recolored to blue and vice-versa, they found that it was the face shapes not the eye colors that were influencing their answers, at least when it came to the male photos.
In the photos, the brown-eyed males had a bigger nose and mouth, a broader chin and more prominent eyebrows positioned closer to each other, compared with the blue-eyed males. These features seemed to convey more trustworthiness to the participants.
In the female photos, the correlation between trustworthiness and face shape was not statistically significant, though the researchers said the trend "was in the same direction."
And overall, there was a negative correlation between perceived dominance and trustworthiness.
For more information, read the interesting report of the study in this month's issue of the Public Library of Science online journal, PLOS ONE.
Please click here for eye and vision news from 2012.
[Page updated April 24, 2015]