Assessment of retinal nerve fiber thickness and optic nerve head blood flow in female patients diagnosed with fibromyalgia syndrome

ABSTRACT Purpose: Numerous neuroimaging and ophthalmic studies suggest optic nerve involvement in fibromyalgia syndrome. To further elucidate the etiopathogenesis of fibromyalgia syndrome, we compared optic nerve head blood flow area and retinal nerve fiber layer thickness between patients and controls and investigated the associations of these measures with fibromyalgia syndrome severity. Methods: Participants were divided into the following three groups according to Fibromyalgia Impact Questionnaire score: mild-moderate fibromyalgia syndrome (Group 1, n=47), severe fibromyalgia syndrome (Group 2, n=38), and healthy controls (Group 3, n=38). The optic nerve head blood flow area and retinal nerve fiber layer thickness were measured by optical coherence tomography angiography and compared among groups by ANOVA. Associations with fibromyalgia syndrome severity were evaluated by Spearman's correlation analysis. Results: Optic nerve head blood flow area did not differ between fibromyalgia syndrome Groups 1 and 2 (1.61 ± 0.08 vs.1.63 ± 0.09 mm2), but it was significantly lower in control Group 3 (1.49 ± 0.10 mm2, all p=0.001). Average retinal nerve fiber layer thickness values were significantly lower in Group 2 (101.18 ± 6.03 mm) than in Group 1 (103.21 ± 10.66 mm) and Group 3 (106.51 ± 8.88 mm) (p=0.041 and 0.020, respectively). The inferotemporal (134.36 ± 12.19 mm) and inferonasal (109.47 ± 16.03 mm) quadrant retinal nerve fiber layer thickness values were significantly lower in Group 2 than in Group 1 [inferotemporal (142.15 ± 17.79 mm), inferonasal (117.94 ± 20.53 mm)] and Group 3 [inferotemporal (144.70 ± 16.25 mm), inferonasal (118.63 ± 19.01 mm)] [inferotemporal, p=0.017 and 0.010, respectively; inferonasal, p=0.047 and 0.045, respectively]. The nasal-superior quadrant retinal nerve fiber layer thickness value was higher in Group 3 (91.08 ± 12.11 mm) than in Group 1 (84.34 ± 13.09 mm) and Group 2 (85.26 ± 13.11 mm) (p=0.031 and 0.038, respectively). A weak correlation was detected between disease severity and optic nerve head blood flow area. Conclusion: Neural and vascular structures of the eye are altered in fibromyalgia syndrome, particularly among severe cases. Therefore, optical coherence tomography angiography may provide valuable information for the diagnosis and elucidation of fibromyalgia syndrome pathophysiology.