Are the eyes the window to whatever’s going wrong with the brain in fibromyalgia? Research published in 2015 and 2016 suggests that it just might be.
Fibromyalgia is widely believed to be a condition of the central nervous system, which includes the brain and spinal column. It also includes the eyes and the structures that help our brains interpret what we see.
Chief among these structures is the optic nerve, which is similar to a cable made up of many smaller fibers.
Among them is a layer of nerves called the retina nerve fiber layer (RNFL).
Those nerve fibers are of special interest to researchers because of other recent work that’s uncovered dysfunction of the small nerve fibers. It suggests that, in people with fibromyalgia, small-fiber neuropathy (nerve damage) may be responsible for at least some of the pain.
In two studies, Spanish researchers have also discovered evidence of neuropathy in the small fibers of the eye.
In the study published in 2015, researchers looked at blood flow to the optic nerve and the RNFL. Blood flow, also called perfusion, is hypothesized to be irregular in several regions of the brains of people with fibromyalgia.
Researchers examined and took photographs of the eyes of 118 people with this condition plus 76 healthy people in the control group.
The photos were then analyzed with special software. The researchers concluded that the fibromyalgia eyes did in fact show low perfusion rates in several sectors, but the only significant difference was in certain RNFL.
Optic Nerve Thinning
The study published in 2016 built on that research, involving many of the same researchers. This time, they included 116 people with fibromyalgia and 144 in the control group.
- a significant decrease in the RNFL in fibromyalgia compared to controls
- a thinning of multiple structures in the eye
- greater optic nerve thinning in those with severe fibromyalgia than in those with a milder case
- greater optic nerve thinning in subgroups without depression than in those with depression
Before now, fibromyalgia has been considered non-neurodegenerative, meaning that no biological structures were being damaged or destroyed as they’re known to be in other neurological diseases such as multiple sclerosis or Alzheimer’s disease.
However, this research suggests that fibromyalgia may, in fact, involve some neurodegeneration in structures inside the central nervous system.
This, combined with earlier research on small nerve fiber damage in the skin, could mean that the degeneration is not confined to the central nervous system but may extend to the peripheral nervous system, which includes the nerves in the limbs, hands, and feet.