Why Are Blue Eyes So Sensitive?
Why are Blue Eyes More Sensitive to Light? – Lighter colored eyes like blue, hazel and green have less of a pigment called ‘melanin’ than brown eyes do. Melanin helps protect the retina from UV damage and blue light, putting those with blue eyes at a higher risk of developing UV-related eye damage.
Why are people with blue eyes sensitive?
Are Blue Eyes or Light Eyes More Sensitive? People with blue or light eyes tend to be more sensitive to light. This is because blue eyes, especially light blue eyes, have less pigment in the iris, making them more translucent. This can cause blue-eyed people to be more susceptible to glare and sunlight, leading to light sensitivity.
Do blue eyes have higher pain tolerance?
Meeting Coverage > APS by Contributing Writer, MedPage Today May 2, 2014 TAMPA – Caucasian women with light-colored eyes – blue or green – appear to tolerate pain better than Caucasian women with brown or hazel eyes, researchers reported here. In a study involving 58 pregnant women – 24 with dark-colored eyes and 34 with light-colored eyes – those with lighter eyes achieved greater reductions in postpartum anxiety (P =0.02), depression ( P =0.08), and catastrophizing/rumination ( P =o.15), said Inna Belfer, MD, of the University of Pittsburgh School of Medicine.
Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
“This is just a pilot study with small number of women,” Belfer told MedPage Today at her poster presentation at the annual scientific meeting of the American Pain Society, Cindy Teng, BA, a medical student at University of Pittsburgh and the lead author of the study, said that another indication that dark-eyed women had greater pain was their increased pain reduction when they were given epidural analgesia.
- They experienced about a 60% reduction in pain at rest compared with about a 45% reduction in pain at rest among the women with light-colored eyes ( P =0.22).
- There was about a 55% reduction in pain during movement among the dark-eyed women, compared with a 40% reduction in pain among the light-eyed patients ( P =0.28).
“These figures in pain reduction after the epidural show a trend, but they are not statistically significant,” Teng told MedPage Today, She suggested that there is more of a reduction in pain with the epidural because those with dark eyes appear to have more sensitivity to pain and therefore may get a stronger impact from pain relief treatment.
- Belfer said that differences in hair color have been linked to resistance to anesthesia, and eye color has been associated with behavior and possibly neural transmission.
- However, there has been limited research examining the relationship between eye color and the human pain experience,” she said.
- Our research is too early to hypothesize why there should be link between eye color and pain.
I suspect there is a genetic component.” She said that the researchers for the pilot study sought to have as homogeneous population as possible, so they selected pregnant Caucasian women. Belfer said further studies would include nonpregnant women and would also look at the relationship between eye color and pain among men.
The women in the current study were recruited from the University of Pittsburgh Magee Women’s Hospital. The researchers administered validated surveys that addressed pain, mood, sleep, and coping behavior both antepartum and postpartum. Physical pain thresholds were assessed through heat stimulation on the skin.
“Research in pain phenotypes and more readily identifiable features like eye color could enhance clinical care and treatment effectiveness, which influence patients’ physical and psychosocial well-being,” Belfer said. She said the researchers were sparked to consider the subject by a water-cooler discussion about eye color and pain.
One of the residents told Belfer, “See, that woman has brown eyes, she’s gonna be trouble.” Gregory Terman, MD, PhD, president-elect of the American Pain Society and director of pain medicine research at the University of Washington in Seattle, told MedPage Today that researchers have been trying to determine why there is such a heterogeneous reaction to pain.
“I don’t know why there would be a relationship between eye color and pain unless it has to do with an genetic link that somehow includes eye color. It is an interesting subject to pursue.” Disclosures Teng and Belfer disclosed no relevant relationships with industry.
Are blue-eyed people related?
Don’t It Make Your Brown Eyes Blue? Blue-eyed? Thank a genetic switch that turns off your body’s ability to make brown pigment in your peepers. Researchers have finally located the mutation that causes blue eyes, and the findings suggest that all blue-eyed humans share a single common ancestor born 6000 to 10,000 years ago.
Researchers have implicated the OCA2 gene in several eye colors. The gene is involved in the production of melanin, a pigment that gives hair and skin their hues. It also codes for brown eyes and can lead to green or hazel eyes when mutated. Despite years of searching, however, scientists have not found a mutation for blue eyes on the gene.
It turns out they were looking in the wrong place. Trying to narrow the site of the mutation, gene mapper Hans Eiberg of the University of Copenhagen and colleagues examined members of a large Danish family, an approach that allowed them to follow DNA as it passed from one generation to another.
Then, by comparing people with brown or blue eyes, including people from Jordan and Turkey, the researchers were able to pinpoint the exact mutation. It wasn’t on the OCA gene but rather on a nearby gene called HERC2, The mutation works like a switch that regulates the OCA gene, the team reports in the January issue of Human Genetics, turning off the production of brown eye color and allowing blue eyes to shine through.
Because blue eye color is found almost exclusively in people of European descent, Eiberg’s team speculates that the mutation traces back to the Neolithic expansion, when people in the Black Sea region migrated to northern Europe 6000 to 10,000 years ago.
- Two other studies, both appearing in this month’s issue of The American Journal of Human Genetics, examined blue eyes in different populations and found the same mutation.
- The researchers also suggested a common ancestor for all blue-eyed individuals.
- These teams, however, did not estimate an age for the mutation.
Geneticist Richard Sturm of the University of Queensland in Brisbane, Australia, an author of one of the papers says that someday scientists may find additional mutations that cause blue eyes but for now, the signs point to a single change. Sturm says that it’s not uncommon for one gene to regulate another, but it is difficult to locate the mutation in the controlling gene.
One of the most cited examples is the mutation involved in lactose tolerance, which is also caused by regulation from outside the gene. Sturm says that such regulating genes may contribute more to genetic diversity than previously thought. The findings also have applications in forensics. Geneticist Manfred Kayser of the Erasmus University Medical Center in Rotterdam, the Netherlands, an author of the other paper that appears in The American Journal of Human Genetics, says if police fully understood mutations behind eye color, for example, then they could use them to determine the eye color of a suspect based solely on DNA evidence.
Geneticist Tony Frudakis of DNAPrint Genomics Inc., a Sarasota, Florida, company that develops genetic-testing products, is shocked that the mutation happened just once. Although there are about 10 ways to get someone with red hair, the scientists found only one way to get someone with blue eyes.
- I would have thought blue eyes arose several times independently,” Frudakis says.
- There are still large questions, though.
- Why did blue eyes persist? Scientists say it is difficult to see how eye color would have an environmental advantage, as skin color does.
- Some theories suggest that women may have played a role in driving the selection.
Perhaps, Kayser says, “the females thought it more exciting to have a male with blue eyes.” Related site : Don’t It Make Your Brown Eyes Blue?
What is blue eye Syndrome?
Definition – Blue eye disease (BED) is the common name for a disease caused by a porcine rubulavirus (Paramyxoviridae; La Piedad Michoacan virus) that is characterized in nursing or growing pigs by central nervous system (CNS) signs and, frequently, by corneal opacities. Signs in sows and boars include various forms of reproductive failure and corneal opacity.