Investigation of corneal sub-basal nerve plexus and dendritic cell density by in vivo confocal microscopy in thyroid-associated ophthalmopathy patients

Abstract

Abstract Purpose To investigate corneal sub-basal nerve plexus (SBP) and dendritic cell (DC) density by in vivo confocal microscopy (IVCM) and the association between corneal involvement and clinical features in thyroid-associated ophthalmopathy patients. Methods Thirty-three patients diagnosed with TAO and thirty-six age- and sex-matched healthy controls were included. Central corneal sub-basal nerve fibers and DC were evaluated with in vivo laser scanning confocal microscopy and analyzed using NeuronJ, a semi-automated ImageJ software and ImageJ's Cell Counter. Results Corneal nerve fiber length (CNFL), corneal nerve fiber density (CNFD), and corneal nerve branch density (CNBD) were significantly reduced in TAO patients compared to healthy controls. The DC density was significantly increased in TAO patients compared to healthy controls (Table 3) (Figs. 1 and 2). No correlation was found between IVCM parameters and thyroid-stimulating hormone (TSH), Graves’ disease duration, The Clinical Activity Score (CAS), and thyroid receptor antibody (Trab) level. There are significant negative correlations between DC density and corneal SBP IVCM parameters, including CNFL, CNFD, and CNBD. Conclusion Decreased sub-basal corneal nerve fibers correlated with increased corneal DC density, indicating corneal nerve loss associated with corneal inflammation in TAO patients. However, elucidation of the exact underlying mechanisms warrants further study.