Why Do Eyes Turn Blue When Blind?
- Pieter Maas
Why do some blind people’s eyes turn white? – However, when blindness is a result of infection of the cornea (the dome in front of the eye), the normally transparent cornea may become white or gray, making it difficult to view the colored part of the eye. In blindness from cataract, the normally black pupil may appear white.
Why do people’s eyes turn blue?
Blog 1. Only 8 Percent of the World’s Population Has Blue Eyes If you have got blue eyes, you might just belong to one of the world’s most exclusive groups without realising it! Since blue eyes are genetically recessive, only 8 percent of the world’s population has blue eyes.
- While blue eyes are significantly less common than brown eyes worldwide, they are frequently found from nationalities located near the Baltic Sea in northern Europe.2.
- There is No Blue Pigment in Blue Irises The colour of our eyes depends on how much melanin is present in the iris.
- Blue eyes get their colour the same way water and the sky get their blue colour — they scatter light so that more blue light reflects back out.
The iris is made up of two layers. For almost everyone — even people with blue eyes — the back layer (called the pigment epithelium) has brown pigment in it. The front layer of the iris (called the stroma) is made up of overlapping fibers and cells. For people with brown eyes, some of the cells also have brown pigment in them.
If there is no pigment at all in this front layer, the fibers scatter and absorb some of the longer wavelengths of light that come in. More blue light gets back out and the eyes appear to be blue.3. Blue Eyes are More Sensitive to Light Melanin in the iris of the eye appears to help protect the back of the eye from damage caused by UV radiation and high-energy visible “blue” light from sunlight and artificial sources of these rays.
Since blue eyes contain less melanin than green, hazel or brown eyes, photophobia is more prevalent in blue eyes compared to darker coloured eyes. For these reasons, having less melanin in your irises means that you need to protect your eyes more from the sun’s UV rays.
- Therefore, it is recommended to those with blue eyes to stay out of the sun for long periods of time and try to wear protective eyewear when you are outdoors.4.
- All Blue-Eyed People May Have A Common Ancestor Originally we all had brown eyes, however, according to researchers at the University of Copenhagen, it appears that a genetic mutation in a single individual in Europe 6,000 to 10,000 years ago led to the development of blue eyes.
Therefore, we can conclude that this genetic mutation is the cause of eye colour of all blue-eyed humans alive on the planet today. What is the genetic mutation? A genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a “switch”, which “turned off” the ability to produce brown eyes.
The OCA2 gene codes for the ‘P protein’, which is involved in the production of melanin (the pigment that determines the colour of our eyes, skin and hair). The “switch”, does not, however, turn off the gene entirely, but rather limits its action to reducing the production of melanin in the iris – effectively “diluting” brown eyes to blue.
According to Hans Eiberg, associate professor in the Department of Cellular and Molecular Medicine from the University of Copenhagen, “From this, we can conclude that all blue-eyed individuals are linked to the same ancestor. They have all inherited the same switch at exactly the same spot in their DNA.” 5.
Blue Eyes at Birth Doesn’t Mean Blue Eyes For Life While blue eyes may be rare, they’re among the most common eye colours at birth. Since the human eye does not have its full adult amount of pigment at birth, most Caucasian babies are born with blue eyes. However, since human melanin tends to develop over time — this causes the child’s eye colour to change as more melanin is produced in the iris during early childhood.6.
People With Blue Eyes May Have a Higher Risk of Alcoholism A new study suggests that individuals with blue eyes are at a higher risk for alcohol dependency compared to those with darker eyes. Therefore, this finding adds further evidence to the idea that alcoholism has a genetic component.
- A study published in American Journal of Medical Genetics, Part B: Neuropsychiatric Genetics found that European Americans with blue eyes had up to 83 percent higher odds of becoming dependent on alcohol, compared with matched controls who had darker eye colours.
- This research suggests that alcoholism has a genetic component linked to genetic sequences that determine eye colour, which may help explain the association.
However, at this stage, the reason for the correlation is still unknown and further research is required to fully understand this correlation in the findings.7. You Can’t Predict the Colour of Your Child’s Eyes Since it was once believed that eye colour — including blue eyes — was a simple genetic trait, many people used to believe that blue-eyed people could only have blue-eyed children.
- Before geneticists fully understood how human eye colour inheritance works, a child’s eye colour to used be used as a paternity test — based on the assumption that you could predict a child’s eye colour if you knew the colour of the parents’ eyes and perhaps the colour of the grandparents’ eyes.
- But geneticists now know that this concept is far more complicated, as eye colour is influenced by an interaction of as many as 16 different genes — not just one or two genes as once thought.
Additionally, the anatomic structure of the iris can also influence eye colour to some degree. In summary, it’s impossible to know for sure if your children will have blue eyes. Even if you and your partner both have blue eyes, that’s no guarantee your child’s eyes will also be blue.
Why do blind eyes go grey?
Science Behind Blind People’s White Eyes – If you’ve ever wondered why some people have bright, beautiful eyes, and others (especially some older adults) seem to have a little bit of a hazy look to their eyes, the answer may be cataracts. A cataract is an accumulation of protein on the eye’s lens.
UV rays – When we are exposed to the sun’s UV rays, even in small doses, our eyes are exposed as well. This exposure increases the chance of developing cataracts. Diabetes – Those with diabetes are even more likely to develop cataracts faster and at a younger age than those who don’t. Medications – Corticosteroids are associated with cataracts if they have been used for a prolonged period of time. Smoking – Those who smoke 15 + cigarettes a day have up to three times greater risk of developing cataracts than those who don’t smoke. Alcohol – Individuals with greater alcohol consumption are more likely to get cataracts than those who don’t drink much or at all.
Why do blind people have blue?
Blind people don’t necessarily have blue irises, but cataracts put a milky film over the cornea, which can look blue in some light.
Can blind people see blue?
About Colour Blindness There are different types of colour blindness and in extremely rare cases people are unable to see any colour at all, but most colour blind people are unable to fully ‘see’ red, green or blue light. The most common forms of colour blindness are collectively known as ‘red/green colour blindness’.
only can’t ‘see’ red and green only confuse red with green, or see reds as greens and greens as reds
None of these statements are true! Being ‘red/green colour blind’ means people with it can easily confuse any colours which have some red or green as part of the whole colour. So someone with red/green colour blindness is likely to confuse blue and purple because they can’t ‘see’ the red element of the colour purple.
See the example of pink, purple and blue pen cases above to understand this effect. For more information about the different colour combinations which cause the most problems, see, Problems can arise across the entire colour spectrum potentially affecting perception of all reds, greens, oranges, browns, purples, pinks and greys.
Even black can be confused as dark red, dark green or dark blue/purple. The best way to understand colour blindness is to compare the ‘normal’ and simulated images throughout our website. The effects of colour vision deficiency can be mild, moderate or severe and people with severe forms often think that their condition is mild and doesn’t really affect them.
Approximately 40% of colour blind pupils leave school unaware that they are colour blind, 60% of colour blind people are likely to experience problems everyday and yet often not realise the full impact. Statistically speaking most people with a moderate form of red/green colour blindness will only be able to identify accurately 5 or so coloured pencils from a standard box of 24 pencil crayons (although they may correctly guess more using their sub-conscious coping strategies).
As they rely heavily on coping strategies, colour blind people often think they have correctly identified a colour because it appears to them as the same colour as other things which they know to be a specific colour. However, coping strategies aren’t always reliable.
What color does blind person see?
I n 2004 Peter König made a special belt : one that always vibrated on the side of it facing north. Put on the belt and face north, and it would vibrate in the front; turn to face west and it vibrated on the right side. König, a cognitive scientist at the University Osnabrück, Germany, gave it to a man named Udo Wächter to wear as part of a pilot study.
After just six weeks, Wächter had developed an amazing and much-improved sense of direction. Even in a town 100 miles away, he could immediately point to his home. You might know the direction of north at any moment, based on your surroundings, but we infer it from landmarks we see around us. We can’t sense north in the same way that a loggerhead turtle, a migrating bird, or even Udo Wächter could.
Dangerous Eye Color Surgery Leaves Man Blind
What does a blind person see? (It seems that blind people get asked this all the time,) Your first guess might be that she sees a vast blackness. But imagine telling a goose (who doesn’t know much about humans) that you can’t sense Earth’s magnetic field.
- The bird, baffled, asks, “So, what do you sense when you change the direction you’re facing??” The answer, of course, is nothing.
- Just as blind people do not sense the color black, we do not sense anything at all in place of our lack of sensations for magnetic fields or ultraviolet light.
- We don’t know what we’re missing.
To try to understand what it might be like to be blind, think about how it “looks” behind your head. When you look at the scene in front of you, it has a boundary. Your visual field extends to each side only so far. If you spread your arms, and draw your hands back until they are no longer visible, what color is the space that your hands occupy? This space does not look black.
It does not look white. It just isn’t. Similarly, people with hemispatial neglect can’t see, and so ignore, one half of their visual field—either the right or left side. They eat only the food on the non-neglected side of their plate, for example. They don’t experience a black blob on the neglected side, blocking their vision.
If they did, they’d intuitively sense that they have a problem. They don’t, just like we don’t sense a problem with not seeing behind us. Blind people might not have perceptually driven visual imagery, but they use their other senses to encode spatial relationships,
For example, suppose you take off your high heels under the table at a restaurant. When it’s time to get up, you might feel around with your feet for them, right them, and put them on, all without use of your eyes. You are able to do this because you are encoding spatial information with your haptic system, or sense of touch.
The blind, too, use their other senses, such as hearing and touch, to form representations of the world. This shows that the sensations (information delivered by organs like our eyes) can be distinct from perceptions (ideas about sensations formed by our brains).
A similar memory encoding can be created with input from different senses. You can get a sense of distance of something from your eyes, ears, hands, and even your nose. All of these senses can map to spatial information that is usually thought of as visual. That is what happened to Mr. Wächter with his belt.
His brain, exhibiting plasticity, was able to map the vibrations felt on the skin of his waist to his sense of direction previously informed only by vision. When the belt experiment was over, Wächter felt lost. For the most part, he did not feel a vague, directionless vibration in place of the real vibrations he’d previously sensed—although he did at times feel some “phantom” vibrations.
Will the blind ever see?
A brain implant lets a blind person see again — without using their eyes
A former science teacher who had been blind for 16 years can see again, thanks to a startling scientific breakthrough.The combination of a brain implant and a prosthetic that incorporates a camera allows her to see basic shapes and even play games — without using her eyes.
How it works: Researchers from Spain and America made a significant breakthrough with the implant placed into Berna Gómez’s brain. After a training period, the implant ultimately allowed her to “see” letters and the outline of objects. Her newfound vision was clear enough that she could play a “Simpsons” video game,,
“One goal of this research is to give a blind person more mobility. It could allow them to identify a person, doorways, or cars easily. It could increase independence and safety.” Richard Normann The implant directly stimulates the visual cortex, the part of the brain that ordinarily receives and processes visual information coming from the retinas.
The team also had to create an artificial retina — essentially, a video camera mounted to a pair of glasses — to provide the visual signal to the implant, bypassing the damaged optic nerve. For six months the researchers worked with Gomez to study how the brain implant impacted her ability to see letters and shapes, according to the study published in, she didn’t experience any adverse problems or concerns.
After a training period, which included playing video games, Gómez’s brain was able to understand visual information that the brain implant was delivering straight to her brain. “These results are very exciting because they demonstrate both safety and efficacy,” said researcher Eduardo Fernández of Miguel Hernández University,,
“We have taken a significant step forward, showing the potential of these types of devices to restore functional vision for people who have lost their vision.” Seeing into the future: About 148 million people in the world have lost their vision because the optic nerve — the link between the eyes and brain — is destroyed, The Science Times.
Conditions like glaucoma or optic nerve atrophy are among the leading causes of blindness. Bypassing the eyes and sending visual information directly to the brain is a promising option for restoring sight for some people. But there is still more work to do. The researchers NPR that past studies have shown it takes 700 electrodes to help a blind person regain mobility.
In this study, the tiny brain implant was just 4 mm square and held 96 electrodes. Still, it only took small electrical currents to stimulate the visual cortex enough to see general shapes. The team hopes to boost their electrode count in further studies, finding the right balance between implant size and visual strength.
Why do blind people carry a white stick?
A primer on the white cane and its uses for the White Cane Safety Day. – July 23, 2021, Today, 15th of October is observed as White Cane Safety Day, which celebrates the symbol of independence — the white cane. The white cane is a long cane that helps someone with low vision or vision loss navigate and avoid obstacles on the road. It is their visual aid that helps identify dents, platform edges, steps, uneven surfaces.
Some of them choose to use a cane to move around while others use it to let people know about their visual impairment. It is important to understand that not all of them are entirely blind or have the same eye condition. There are different types of canes like mushroom tip, roller tip or straight tip, used for different purposes.
Here’s a little information about some of them:
Guide cane: Used to identify a step or dent on any surface. It is also to warn people about their visual impairment. Long cane: Avoid obstacles on the road and some use it for long journeys. Symbol cane: It is a short cane which does not usually touch the ground. Can be folded and handheld to let people know about their difficulty in viewing. All white cane: Typically used by people who are totally blind.
Red and White cane: Indicates that a person using it is deaf and blind.
Caption: A red and white cane
White cane with red bottom: This cane indicates that the person has low vision.
Caption: A white cane with red bottom
Colorful cane: Some see the cane as an extension of their personality. They prefer to customise the canes to suit their liking.
There are instances of people mistaking the canes for selfie stick, mallet or even a sword. Yes, that seems like quite a leap! It would make a world of difference to be well informed and inclusive as a society. Offer to help but ask them if they need assistance before dragging their sticks.
Who is the most famous blind person?
Main Digest – Blindness is the condition of lacking visual perception due to physiological or neurological factors. Total blindness is the complete lack of form and light perception and is clinically recorded as “NLP,” an abbreviation for “no light perception.In order to determine which people may need special assistance because of their visual disabilities, various governmental jurisdictions have formulated more complex definitions referred to as legal blindness. About This Image: Fig.1 – Perhaps the most well known blind person was Helen Adams Keller (June 27, 1880 – June 1, 1968). Perhaps the most well known blind person was Helen Adams Keller (fig.1), (June 27, 1880 – June 1, 1968), an American author, political activist, and lecturer.
- Helen Keller was the first deaf-blind person to earn a bachelor of arts degree.
- A prolific author, Keller was well-traveled and outspoken in her convictions.
- A member of the Socialist Party of America and the Industrial Workers of the World, she campaigned for women’s suffrage, labor rights, socialism, antimilitarism, and other similar causes.
Helen Keller went on to become a world-famous speaker and author. She was an advocate for people with disabilities, and numerous other causes. The Deaf community was widely impacted by her. She traveled to twenty-five different countries giving motivational speeches about Deaf people’s conditions.
She was a suffragette, pacifist, radical socialist, and birth control supporter. Listed below are other well known people who had or have a vision impairment including total blindness, sight conditions, and blindness in one eye. NOTE: If you know of a discrepancy in this list please contact us so we can amend the entry.
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Does eye color have an effect on blindness?
Your eye color is 100% linked to specific genes. And so are many of the most common eye conditions and eye diseases leading to vision loss. However, for the most part, your eye color doesn’t put you at risk for vision conditions (an exception being albinism ). However, the color of your irises can make a bit of a difference in how you view the world.
Does vision affect eye color?
Dark. Whether you have light or dark colored eyes, your eye color does actually have an impact on your vision. If you have a lighter eye color, your eyes are more sensitive to light because you have less pigment and melanin in your irises to protect your eyes from the sun.