Are the eyes the window on what is wrong with the brain in fibromyalgia? Research published in 2015 and 2016 suggests that this may be the case.
Fibromyalgia is generally thought to be a disorder of the central nervous system, which includes the brain and spine. It also includes the eyes and structures that help our brain interpret what we see.
The optic nerve, which looks like a cable made up of many smaller fibers, is the main one of these structures.
Among them is a layer of nerves called retinal nerve fiber layer (RNFL).
Nerve fibers are of particular interest to researchers because of other recent work that reveals dysfunction of small nerve fibers. He suggests that in people with fibromyalgia, a small-fiber neuropathy (nerve injury) may be responsible for at least some of the pain.
In two studies, Spanish researchers also found signs of neuropathy in the small fibers of the eye.
Blood circulation problems
In the study published in 2015, researchers examined blood flow to the optic nerve and the RNFL. Blood flow, also called perfusion, is thought to be irregular in many brain regions of people with fibromyalgia.
The researchers examined and photographed the eyes of 118 people with this disease, as well as 76 healthy people in the control group.
The photos were then analyzed with special software. The researchers concluded that fibromyalgia eyes actually had low perfusion rates in many areas, but the only significant difference was in some RNFLs.
Thinning of the optic nerve
The study published in 2016 builds on this research and involves many of the same researchers. This time, they included 116 people with fibromyalgia and 144 in the control group.
a significant decrease in RNFL in fibromyalgia compared to controls
a thinning of several structures in the eye
greater thinning of the optic nerve in patients with severe fibromyalgia than in those with a less severe case
greater thinning of the optic nerve in subgroups without depression than in those with depression
Until now, fibromyalgia was considered non-neurodegenerative, that is to say that no biological structure was damaged or destroyed, as is known in other neurological diseases such as multiple sclerosis or Alzheimer’s disease.
However, this research suggests that fibromyalgia may actually involve neurodegeneration in central nervous system structures.
This, combined with previous research on the damage of small nerve fibers in the skin, could mean that degeneration is not limited to the central nervous system but can extend to the peripheral nervous system, which includes the nerves of the limbs, hands and feet.
The relationship between fibromyalgia, optic nerve and neurodegeneration
Fibromyalgia has always been a problem for doctors. We have pain but no obvious cause. If this research is accurate, which we will not know until it has been reproduced, it could mean that our pain comes from a very understandable source. After all, neuropathic pain has long been recognized.
Suddenly, this makes our “mysterious” pain not mysterious.
On the other hand, it opens new doors to interrogation. If we have damaged nerves, why? What causes the damage?
Potential candidates could include autoimmunity, which would imply that the immune system becomes dangerous and attacks the nerves as if they were bacteria or viruses, as well as problems related to how the body uses substances that develop or maintain the nerves.
Researchers have long speculated about possible autoimmunity in fibromyalgia, but so far, we have no solid evidence in this regard. Now that researchers have discovered the actual damage, they can better understand where to look for autoimmune activity.
They may also be able to detect shortcomings or inefficiencies in the way the nerves are maintained.
With regard to diagnostic tests, it is too early to say whether eye abnormalities could lead to a more objective test than we currently have. In this case, the detection of fibromyalgia would be a major advance.
Since thinning was worse in more severe cases, it could provide physicians with a marker to track treatment progress.
It is also possible that these discoveries lead to targeted treatments.
We will not fully understand the impact of this research for some time, as any advances in diagnosis and treatment should occur after further research confirms or contradicts these findings.
Garcia-Martine E., Garcia-Campayo, Puebla-Guedea, M. et al. Fibromyalgia correlates with the thinning of the retinal nerve fiber layer. PLoS One. September 1, 2016; 11 (9): e0161574.
Pilar Bambo, Garcia-Martin, F, Gutierrez-Ruiz, et al. Study of the changes in the perfusion in the optical disc of patients with fibromyalgia syndrome using the new colorimetric analysis software. French Journal of Ophthalmology. 2015 Sep; 38 (7): 580-7.