Pos1259 Evaluation of Conjunctival Vascularization Through Anterior Segment-Optical Coherence Tomography Angiography in Patients With Primary Sjögren’s Syndrome

Background: Primary Sjögren's syndrome (pSS) is an autoimmune systemic disease that involves the exocrine glands as its primary target. Particularly, lacrimal glands are characterized by inflammatory infiltrate, cytokine production and epithelial cells apoptosis, and the main clinical manifestation is the keratoconjunctivitis sicca. Optical coherence tomography angiography (OCTA) is a non-invasive diagnostic technique for imaging the retinal vasculature, and it has been evaluated for its ability to detect subclinical microvascular alterations in systemic diseases. Role of OCTA in the anterior segment (AS, AS-OCTA) evaluation has been studied in inflammatory conditions, such as uveitis and scleritis, although a standardized protocol is lacking [1]. A recent study reported that pSS had a lower retinal vascular density, but a higher conjunctival vascularization compared to healthy controls (HC) at the OCTA evaluation (2). Objectives: Aim of this study is to evaluate conjunctival vascularization in pSS patients compared to a group of HC and its correlation with systemic disease parameters. Methods: Cross-sectional pilot study enrolling consecutive pSS patients and HC, comparable for age and sex. Subjects with concomitant infectious/inflammatory ocular disorders were excluded. Demographic, clinical and laboratory data were collected, such as age, sex, smoking habit, disease duration, erythrocyte sedimentation rate, C-reactive protein, IgG, IgA, IgM and complement levels, rheumatoid factor, antinuclear, anti-SSA and anti-SSB antibody positivity, EULAR SS disease activity index and EULAR SS Patient-Reported Index, ongoing antirheumatic treatments. Patients and HC underwent an ophthalmological evaluation including Schirmer's test, tears breakup time (BUT) test, ocular surface staining graded through the Oxford scale and AS-OCTA. OCTA en face images were processed using the software Mthlab and transformed into a gray scale with pixel ranging from 0 to 255. A threshold equal to 110 was set to identify vessels and their percentage was calculated. Statistical analysis was accomplished using Pearson/Spearman, t-test/Mann-Whitney or χ2test when appropriate. Receiver Operating Characteristic (ROC) curve analysis was performed in pSS and HC to evaluate AS-OCTA diagnostic accuracy. Results: 35 pSS patients and 15 HC were enrolled. Demographic and clinical data of the study population are showed in table 1. Schirmer and BUT values were significantly reduced in pSS compared to HC, while OSDI resulted higher in pSS. According to AS-OCTA data, pSS showed a higher vascularization compared to HC (Table 1). According to patients' clinical parameters, a negative correlation resulted between AS-OCTA vascular density and both C3 (p=0.03, r=-0.3) and C4 levels (p=0.02, r=-0.3), while a positive correlation with disease duration was observed (p=0.01, r=0.3). Moreover, patients under prednisone (PDN) treatment had higher AS-OCTA values compared to those not assuming PDN (p=0.03). ROC curves and related areas under the curve (AUC) showed a medium-high accuracy of the diagnostic test (AUC 0.77, CI 95% 0.68-0.87, p<0.0001, cut-off value >0.143, sensitivity 80.3%, specificity 63.3%, Likelihood ratio 2.19). Conclusion: Our results show that pSS patients have a more pronounced vascularization of the conjunctiva compared to HC, probably secondary to an inflammatory response. Moreover, anterior vascular density seems to be correlated with disease duration and systemic pSS activity. In conclusion, AS-OCTA could represent a valid tool to better evaluate conjunctival inflammation in pSS. REFERENCES: [1] Pichi F, Roberts P, Neri P. The broad spectrum of application of optical coherence tomography angiography to the anterior segment of the eye in inflammatory conditions: a review of the literature. J Ophthalmic Inflamm Infect. 2019 Sep 4;9(1):18; [2] Yang QC, Yao F, Li QY, Chen MJ, Zhang LJ, Shu HY et al. Ocular microvascular alteration in Sjögren syndrome. Quant Imaging Med Surg. 2022 Feb;12(2):1324-1335. Acknowledgements: NIL. Disclosure of Interests: None declared.