Abstract
Purpose: :
To compare ocular and visual findings of subjects with fibromyalgia (FM) and healthy controls using in vivo corneal confocal microscopy (IVCM).
Methods: :
Prospective, IRB approved study comparing ophthalmic signs and symptoms of 19 subjects with FM and 19 healthy controls (HC). IVCM, Schirmer test, ocular surface stain, tear break up time (TBUT), corneal sensation, Ocular Surface Disease Index (OSDI) and NEI Visual Functioning Questionnaire (VFQ-25) were assessed in all subjects. Two-tailed t-tests were performed to compare subjects with FM and HC. Pearson correlation analyses were used to assess relationships between IVCM and clinical findings of ocular surface disease.
Results: :
There were significant differences in IVCM parameters between subjects with FM and HC. Subbasal nerve density was lower in FM with decreased number of nerves (p=0.019) and decreased total nerve length (p=0.0004). There was also a trend towards increased nerve tortuosity in subjects with FM (p=0.075). Basal epithelial cell density was significantly lower in FM than in HC (p=0.007). Corneal thickness, epithelial thickness, stromal cell and endothelial cell densities were similar in the two groups. There were no significant differences in Schirmer testing, ocular surface staining or TBUT between the 2 groups. Patients with FM had increased corneal sensation (p=0.044), higher OSDI scores (p<0.0001), and lower VFQ-25 scores (p=0.0001), indicating more ocular and visual symptoms in this cohort. OSDI scores correlated with the number of subbasal nerves (r=-0.41, p=0.01), overall nerve length (r=-0.35, p=0.03), and nerve tortuosity (r=0.41, p=0.009). VFQ-25 scores correlated with the number of subbasal nerves (r=0. 54, p=.0005) and nerve tortuosity (r=-0.36, p=0.03). There was also a correlation of number of corneal nerves with age (r=-0.37, p=0.02) and overall nerve length with corneal sensation (r=-0.33, p=0.04).
Conclusions: :
Our preliminary results indicate that subjects with fibromyalgia have decreased subbasal corneal nerve density. Clinical correlations indicate an association between the subbasal nerve plexus and ocular and visual symptoms.
Keywords: microscopy: confocal/tunneling • cornea: tears/tear film/dry eye • cornea: clinical science