Bernhard Sabel, Ph.D., a medical psychology professor at Otto von Guericke University in Germany, is more observant than the average person. Or, at least, the average ophthalmologist: Using his own clinical observations, a decades-long literature review, and some very intensive Googling, Sabel and his team just published an EPMA Journal paper showing a link between high stress and vision loss that has eluded eye experts for years — but has likely been troubling stressed-out humans for much longer.

In the paper, published Tuesday, Sabel stresses how important it is that scientists pay attention to the needs of everyday people. “Patients who suffer vision loss report that they had the vision loss at the time of very serious life stress events, such as marital problems,” he tells Inverse. “But ophthalmologists are not aware of this and they downplay it as only psychology. There is a large disconnect between the science and what the public needs.”

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If you replicate Sabel search terms in Web of Science, another host database for scientific papers, you see that the amount of papers linking psychological factors and vision loss is pretty low, except when things really got going for one year in 2016. So there is a demonstrated gap in the literature. 

Sabel, who estimates that 70 percent of the patients he treats feels there is a connection between prolonged stress and their vision loss, decided to take action. To see whether this was actually a widespread concern, he entered a host of search terms related to vision and stress, like “psychology vision loss,” into Medline, an online database that catalogs scientific papers. He then compared those results to the amount of Google hits for the same search terms to gauge public interest. Sabel found that there were 10,000 Google searches for every peer-reviewed paper, which, to him, indicated that there was a public demand for more research on this. (He took into account, of course, the fact that there will always be more Google hits than scientific studies because of the rigorous nature of peer review; you can’t just throw anything up on Medline, but Google isn’t in the business of reviewing posts for accuracy.)

Sabel started looking for a biological relationship between stress and eye health — in particular, an increase in stress hormones and vascular dysregulation, a major contributing factor to diseases of the eye that degrade the retina, like glaucoma. He relied on case studies gleaned from his extensive literature review.

“Usually there must be a genetic susceptibility and our hunch is, although I couldn’t prove it, is that it has to do with the cellular function of the endothelial cells which make up the blood vessel walls,” Sabel says. “They are exposed to stress hormones such as cortisol or adrenaline, and they become dysfunctional.” This dysfunction, he explains, would lead the walls of the endothelial cells to constrict, reducing blood flow to crucial areas of the brain, such as the neurons that feed directly into the retina.

“The neurons in the retina in the brain are deprived of oxygen and glucose,” he continues. “It doesn’t mean they will necessarily die, but it does mean that they are impaired in their function.”

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Sabel's research points to a type of perfect storm between genetics, stress-coping and vascular dysfunction  that can cause vision loss. 

Sabel’s genetic hypothesis is buttressed by the work of Josef Flammer, Ph.D., a well-known ophthalmologist at the University of Basel. He coined the term “Flammer Syndrome,” which describes an inherited genetic disposition toward diseases like glaucoma, demonstrated vascular dysregulation, and poor stress coping mechanisms.

“Typically, the blood vessels of the subjects with Flammer syndrome react differently to a number of stimuli, such as cold and physical or emotional stress,” writes Katarzyna Konieczka, Ph.D., a glaucoma specialist also at the University of Basel in a 2014 paper. She also notes that the syndrome is more common in women than men and that the parents of those demonstrating Flammer syndrome also report similar tendencies, underlining the hypothesis that it is an inherited trait.

Sabel’s paper goes on to describe a type of perfect storm that is required for someone to experience stress-related vision loss. First, someone has to have a genetic predisposition to stress-regulated vascular dysregulation (like Flammer Syndrome). Then, they’d have to be constantly overwhelmed by stressful stimuli that would trigger an incessant flow of stress-related hormones or, in some cases, experience a traumatic event:

“If a person experiences that [stress] for years or decades, and then there’s an acute event that adds to high stress that can trigger a vascular problem,” he explains.

Sabel is adamant that stress is both cause and effect – particularly in the field of ophthalmology. Patients tend to experience more stress as they cope with the realities of going blind, creating a vicious circle. In the patients he has treated, he has seen improvements in those who make peace with their condition, which can at least eliminate the stress-induced elements of retinal degrading, but it’s not a perfect solution. He notices that many quick to dismiss other forms of stress are psychosomatic symptoms with no real biological effect, despite evidence that they can produce very real biological changes.

“Generally, psychological issues should be taken more seriously, because that’s a way that patients suffer the most,” Sabel says. “People need to understand the biological connection between the mind and the body.”