It’s not in your head, but possibly related to the color of your eyes and that’s why you feel more pain.

Look in the mirror. What color are your eyes? Brown? Blue? Green? Does it matter about anything other than how good you think you look or what other people think you look like?

Eye coloring has a particular attraction, and that’s what drove the market for colored contact lenses, where people could change from brown to green to blue or even purple or wilder eye designs. Of course, you’ve seen the entertainer Marilyn Manson and what he’s done to his eyes.

What you see staring back at you in the mirror might hold clues about how much pain you can handle — and it’s not your imagination. They say the eyes are the mirrors of the soul, but they may also indicate something else — something you may never have realized and that science is discovering.

Scientists have been quietly studying something that sounds almost too strange to be true: your eye color may predict how sensitive you are to pain. This isn’t some folk tale anyone passed down to you. Today, researchers at major universities have been investigating this connection for over a decade, and their findings could change how doctors treat pain in the future. This would be a very good start to improving pain treatment for many individuals who have been discriminated against in this care.

Why Your Eyes Matter More Than You Think

Most of us think our eye color is just a random trait we inherited from our parents — nice to look at, but not particularly important. But your eyes are actually windows into your body’s pain-processing system.

The key player in this story is something called melanin. You’ve probably heard of melanin before — it’s the same stuff that determines your skin color and how easily you tan. But melanin does much more than protect you from sunburn. The same genetic pathways that control melanin production in your eyes also influence how your nervous system handles pain signals.

Now that they’re finding that in research, it seems so simple to add it to the considerations for pain management. But are they doing that? Is everybody keeping up on this research? It should cause concern for all of us if they aren’t.

People with brown eyes have lots of melanin packed into their irises. Those with blue or green eyes have much less. And this difference might explain why some people wince at a paper cut while others barely flinch during medical procedures. I’ve been an unfortunate bystander when I heard a healthcare professional express a belief that people of color didn’t need as much pain medication, “because they don’t feel pain the way we do.”

I wasn’t sure if that was correct because I didn’t have the science to know. Now, I am reminded of some of those horrific slave photographs in the Harvard Peabody Museum.

What the Research Actually Shows

Dr. Inna Belfer from the University of Pittsburgh has been leading some of the most interesting work in this area. Her team studied women during childbirth — one of the most intense pain experiences humans face. What they discovered was eye-opening: women with dark brown or hazel eyes showed more signs of distress during labor than women with light-colored eyes.

The dark-eyed women didn’t just experience more pain during the actual delivery. They also had more trouble sleeping because of pain, felt more discomfort when resting, and were more likely to develop depression related to their pain experience.

But there’s a twist to this story. Those same dark-eyed individuals often respond better to pain medications. Their nervous systems are more reactive, which means they feel pain more intensely, but they also get more dramatic relief from treatments that work.

I recall standing in a patient’s room in a hospital where a Hispanic woman had a hysterectomy and was asking the female gynecologist for more pain relief. The gynecologist refused and told her she was being discharged. I couldn’t understand why she wouldn’t give her more pain medication when there was a drip available that could have been made ready for her. To me, it reeked of bias. But I had no say in the matter because I was visiting a friend, another patient.

A 2024 study published in Pain Research and Management looked at women having dental work. The researchers found that eye color affected both how much pain the women felt and how well the anesthesia worked. While the results are still being debated, the pattern keeps showing up: physical characteristics like eye color seem to influence our pain experience.

The Science Behind the Connection

So what’s actually happening in your body? It all comes down to genetics and brain chemistry.

The genes that produce melanin are part of a complex system that also affects your nervous system. When you have more melanin (and darker eyes), certain chemical messengers in your brain work differently. These neurotransmitters control how pain signals travel from your body to your brain.

Think of it like this: if pain signals are cars driving on a highway to your brain, people with different eye colors have different speed limits on their highways. Some people’s pain signals cruise along slowly, while others race to the brain at top speed.

Recent research has uncovered even more specific mechanisms. Scientists at Massachusetts General Hospital found that the same receptor that determines red hair color — the melanocortin-1 receptor — also affects pain sensitivity. When this receptor doesn’t work properly (as in people with red hair), it changes the balance of natural pain-blocking and pain-enhancing chemicals in the body. The term ‘flaming red hair’ may indicate more than we thought.

What This Means for Different Eye Colors

Brown Eyes: The Sensitive Responders People with brown or hazel eyes tend to be more sensitive to pain, but this isn’t necessarily a bad thing. Research shows they often respond better to pain medications. Their nervous systems are more reactive, which means they feel pain more intensely, but they also respond more dramatically to treatments.

Light Eyes: The Natural Pain Blockers People with blue, green, or light-colored eyes seem to have built-in biological pain tolerance. The lower melanin levels in their eyes, according to research, correlate with brain chemistry that naturally dampens pain signals. A 2017 study found that people with dark eyes and hair showed higher pain sensitivity when their hands were placed in ice water compared to those with light features.

Red Hair: A Special Case Redheads are in a category of their own. Multiple studies have shown they’re more resistant to certain types of anesthesia and may need higher doses of pain medication for some procedures. But who thinks of this? Are anesthesiologists sufficiently trained to notice this? Yet they also seem to have higher pain thresholds for certain types of pain stimuli. One of my grandmothers had incredibly red hair until the day she died in her early 50s. I hadn’t been born yet, but I wonder how she was treated in the hospital for her pain.

The Real-World Impact

This research goes beyond academic curiosity. Understanding the connection between physical traits and pain could revolutionize medical practice. Imagine walking into a doctor’s office where your eye color helps predict how you’ll respond to different pain treatments.

Think of how normal it would be to receive adequate pain medication and not have to feel like you need to plead for it. Some patients, indeed, have to beg for it, and then they are seen as medication-seeking. I recall one man with a particular birth defect in his spine (spina bifida) who requires pain medication. He was always having to go hat-in-hand to his specialist, who reluctantly gave him less medication than he needed. The man now advocates for pain medication for those with specific medical needs. I wonder how well he will treat this research, and I hope he sees it.

Some dentists are already paying attention to this research. The 2024 dental study showed that eye color affected both pain perception and healing time after procedures. While the findings are still being studied, healthcare providers are beginning to recognize that visible characteristics might play a role in personalized pain management.

The Bigger Picture and Important Limitations

Of course, eye color isn’t the only thing that affects how you experience pain. Your age, gender, overall health, stress levels, cultural background, and life experiences all play important roles. Eye color is just one piece of a much larger, more complex puzzle.

It’s also crucial to understand the limitations of this research. Most studies have been small, often focusing on specific populations like women during childbirth or dental patients. The science isn’t settled yet, and there’s more work to be done. But we now have something to look into more intensively in terms of pain management.

Research Biases We Need to Address

This field of research has some important biases that affect how we should interpret the findings:

Limited Demographics: Most studies have focused primarily on women and people of European descent. We don’t know if these patterns hold true across all racial and ethnic groups.

Small Sample Sizes: Many studies have included fewer than 100 participants, which makes it difficult to draw broad conclusions. In other words, what we call the universe of patients is still awaiting results from larger, multi-year studies.

Cultural and Social Factors: Pain expression varies significantly across cultures, but this research hasn’t adequately accounted for these differences. In some cultures, it’s not acceptable to admit to having pain; therefore, we don’t know how research studies there would fare.

Systemic Healthcare Bias: Research has shown that medical professionals often treat pain differently based on patients’ race and gender, which could skew study results. Consider how many women are seen as anxious when what they are experiencing is an actual, painful condition. Recall the woman who had the gynecologic surgery I mentioned earlier in this article.

Publication Bias: Studies showing connections are more likely to be published than those showing no relationship, which might make the evidence seem stronger than it actually is.

Researchers are often captives of the “publish or perish” mentality and funding that is aimed at proving something, such as a medication's efficacy. How many professional publications publish studies that disprove a medication or find nothing? I know a healthcare professional who discovered something that didn’t make it to publication, but it earned him a patent that made him a millionaire.

Looking Forward

As genetic testing becomes more common and affordable, we’re likely to see much more research connecting physical traits to health outcomes. Your eye color might just be the tip of the iceberg. Scientists are currently studying how pigmentation affects drug metabolism, disease risk, and other biological processes.

One thing is clear: our physical characteristics have a more complex and fascinating relationship with our internal experiences than we previously thought. Your eye color might be providing biological information that could lead to better, more personalized medical care in the future.

While we wait for more research to confirm and build upon these findings, it’s exciting to think that something as simple as eye color could someday help doctors provide better pain relief for everyone, especially for those who need it.