You may have heard that red heads experience more pain. It is also common for different ethnic groups to show a variety of responses to pain. Now researchers at University of Pittsburgh School of Medicine in Pennsylvania have tested whether eye color affects pain tolerance.
The study involved 58 pregnant women who all gave birth at UPMC Magee Women's Hospital. The women were all Caucasian, 24 had dark colored eyes (brown or hazel) and 34 had light colored eyes (green or blue).
The researchers assessed antepartum and postpartum pain, mood, sleep and coping using standard surveys that rank these types of subjective characteristics.
What was found was that the dark-eyed women experienced more pain, more anxiety, increased sleep disturbances and were more likely to be depressed than their light-eyed counter parts.
Now it is important to note, the increase was not considered to be statistically significant. The researchers indicate that the results are only considered to show a trend.
The lead researcher Inna Belfer, MD, PhD stated, “Due to the small sample size, we can't get compelling evidence for our findings, but we do feel that our study has revealed patterns that warrant further studies.”
Belfer went on to say that the response to pain could also be genetic and that there is limited previous research available that has examined pain perception and eye color.
Gregory Terman, MD, PhD, president-elect of the American Pain Society and director of pain medicine research at the University of Washington in Seattle, also said that it is unknown as to why there would be a connection between pain response and eye color.
He too stated that it may be due to genetics. Terman said that further research could be interesting.
Commenters on the news reports on this study brought out a number of points that could be in play. One person said that pain related to pregnancy may not be applicable to pain associated with other conditions. Hormones are an obvious variable in pregnancy pain.
Another questioned where the control group was in this study. Pain response would need to have been monitored with eye color and other painful experiences in order to compare.
Someone wanted to know what the vitamin D levels were in the patients. Perhaps those with darker eyes had darker skin and had lower vitamin D levels, which could have contributed to higher pain levels.
Most commenters felt that the study was simply too small, with only 58 patients to draw any real conclusions from, and that cultural responses may be involved.
Dr. Belfer indicated that further studies would include nonpregnant women, and would also look at the relationship between eye color and pain among men.
The study results were presented at the American Pain Society 2014 Meeting. Dr. Belfer and Dr. Terman have disclosed no relevant financial relationships.
Patients' Eye Color a Clue to Pain Tolerance. Medpage.today. Retrieved May 18, 2014.
Does Eye Color Predict Response to Pain? Medscape Nurses.com. Retrieved May 18, 2014.
Belfer, Inna . Academic Editors: J. A. Castro and T. Shikano. Nature and Nurture of Human Pain. Scientifica Volume 2013 (2013), Article ID 415279, 19 pages.
Source reference: Teng C, et al "Correlation between eye color and pain phenotypes in healthy women" American Pain Society 2014; Abstract 197.
Michele is an R.N. freelance writer with a special interest in woman’s healthcare and quality of care issues. Other articles by Michele are at www.helium.com/users/487540/show_articles
Edited by Jody Smith