Fibromyalgia syndrome and the eye-Implications in corneal ultrastructure on confocal microscopy.

Abstract

Fibromyalgia is a chronic systemic disorder associated with varied manifestations ranging from fatigue, sleep disturbances, headaches, muscular pain, cognitive issues, or even without symptoms. It is also known to be associated with chronic neuropathic pain.[1,2] Ocular features described include severe pain, necrotizing scleritis, and changes in optic disc perfusion.[3] Small fiber neuropathy and dysautonomia symptoms correlate with corneal denervation more commonly in women with fibromyalgia. These nerve plexus features were found to be associated with neuropathic pain and fibromyalgia in previous studies.[4] These patients have a higher incidence of dry eye disease as compared to the normal population.[5,6] Approximately 50% of patients with fibromyalgia have damage to small unmyelinated nerve fibers around the body.[7] Small fiber polyneuropathy may cause symptoms sometimes identified as fibromyalgia.[8] A skin punch biopsy is a sensitive and specific test that demonstrates the reduction in nerve fiber density associated with small fiber neuropathy. In vivo confocal microscopy (IVCM) is a noninvasive tool that can demonstrate nerve-related changes in the cornea and hence serve as an adjunct to skin biopsy for diagnosis and evaluation of the disease.[9] This photoessay highlights the nerve-related changes and the presence of microneuromas in the cornea and the use of IVCM in aiding in the diagnosis and management of these patients. Case Reports Three patients previously diagnosed with fibromyalgia presented with ocular pain and mild mixed dry eye. IVCM showed decreased corneal nerve fiber branching density with microneuromas in the cornea [Fig. 1]. They were on systemic therapy for chronic pain and their ocular condition was managed with topical anti-inflammatory and lubricating eye drops. These patients can be at a risk for postoperative dry eye and wound-healing complications and should be evaluated in detail preoperatively to avoid this.Figure 1: (a, b, and c) show microneuromas in the subbasal nerve plexus on IVCM of all three patients with fibromyalgia and dry eye. Figure d shows reduced nerve density, e shows altered nerve morphology and f shows the image used for the calculation of nerve density using the CCMetrics softwareFinancial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.