Diagnosing fibromyalgia (FM) can be difficult for clinicians because there is no specific diagnostic test and they often rely on a group of symptoms described by their patients.
Now, in a study titled “Fibromyalgia Is Correlated with Retinal Nerve Fiber Layer Thinning,” published in the journal PloS One, researchers revealed that a noninvasive eye examination can aid in diagnosing fibromyalgia.
Imaging techniques such as MRI can detect neuronal changes in pain-related brain regions of fibromyalgia patients. However, these types of exams are expensive and not always available in clinical practices. This led researchers to investigate visual loss in fibromyalgia patients, since it is a hallmark of neuronal dysfunction easily detected by routine tests.
The research team examined the visual function of 116 fibromyalgia patients and 144 age-matched healthy controls. Researchers used optical coherence tomography (OCT) to measure a layer of nerve fibers that coats the eye, known as the retinal nerve fiber layer (RNFL).
“The ophthalmologic tests described in this study allow for the eye to be utilized as a ‘window’ to the central nervous system, specifically to directly observe the axons in the optic nerve,” the authors wrote in their report.
Ophthalmologists routinely use OCT to diagnose diseases such as glaucoma and diabetic retinopathy because it is noninvasive, inexpensive, fast, and comfortable for the patient. Using this same technique, researchers found a significant decrease in the thickness of RNFL in fibromyalgia patients, even in those with mild fibromyalgia, according to the Fibromyalgia Impact Questionnaire (FIQ).
From the fibromyalgia patients analyzed, OCT distinguished those with biologic fibromyalgia (low depression but high sensitivity to pain), compared to patients suffering from depressive or atypical fibromyalgia.
Future studies with more fibromyalgia patients followed by longer periods will be required to confirm the use of OCT as a diagnostic tool. These studies will also confirm whether OCT can be used to follow disease progression, to identify patients with worse prognoses or at higher risk for loss of quality of life, and to measure treatment effectiveness.
“Obviously, fibromyalgia patients should be diagnosed and followed-up by a rheumatologist, but ophthalmologic tests are new, noninvasive, and cost-effective tools that can be used to facilitate the diagnosis of fibromyalgia and may reduce the expenses associated with diagnosis of this disease,” the authors concluded.