Exploring corneal and peripapillary biomarkers in patients with Sjögren’s Syndrome

Abstract

Purpose : Subbasal corneal nerve plexus (SNP) is the most densely innervated body structure. Inflammatory processes in patients with primary Sjögren's syndrome (pSS) can lead to a change in corneal tropism and damage to the trigeminal nerve, which could correlate with the loss of retinal nerve fibers. The aim of our study was to investigate the corneal, optic nerve metrics as well as the peripapillary microvasculature and to identify potential ocular biomarkers for neuro/microvascular changes in patients with pSS.

Methods : Central cornea images were prospectively captured from 48 eyes with clinically diagnosed pSS and 38 eyes of age-matched healthy controls using In-vivo corneal confocal microscopy (IVCCM) (Heidelberg Retina Tomograph Rostock Cornea Module - HRT III RCM). Corneal nerve fiber length (CNFL), fiber density (CNFD), branching density (CNBD), total fiber branching density (CTBD), fiber area (CNFA), fiber width (CNFW) and fractal dimension (CNFrac) were measured with ACC Metrics software. OCTA and SD-OCT scans were obtained using SPECTRALIS® II (Heidelberg Engineering, Germany). RNFL and BMO were analyzed with the built-in software. Peripapillary OCTA images (2.9x2.9mm) were analyzed using Erlangen-Angio-Tool. Peripapillary Vessel Area Density (pVAD) was measured at the level of nerve fibre layer plexus (NFLVP) in the innermost circle c1.

Results : Patients with pSS had significantly lower values of CNFD and a higher value of CNFW compared to controls (CNFD: 22.4±8.3 vs. 26.2±7.6 fibres/mm², Cohen`s D 0.47; CNFW: 0.022±0.001 vs. 0.021±0.001 mm/mm<sup>2</sup>, Cohen`s D 0.52; always p<0.05). There were no statistically significant differences between groups for RNFL, BMO and pVAD measurements. No correlation was found between pVAD and RNFL/ SNP. Correlation analysis for RNFL showed a significant correlation with CNFL (ρ = .246), CTBD (ρ = .245), and CNFrac (ρ = .311) (always p< 0.05). Correlation analysis for BMO showed a significant correlation with CNFD (ρ = .291), CNFL (ρ = .289) and CNFrac (ρ = .252) (always p< 0.05).

Conclusions : Patients with pSS have a lower CNFD and thicker corneal nerves compared to healthy eyes. Nerve fibre loss and swelling indicate an ongoing corneal inflammatory process. A low to moderate positive correlation between the SNP and optic nerve metrics suggest a link between peripheral and central nerve changes. Peripapillary microvasculature does not seem to be altered in patients with pSS.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.