Conjunctival vessel density as inflammatory ocular surface marker in systemic autoimmune disease.

Aims/Purpose: Autoimmune diseases are characterized by a pro‐inflammatory environment, with over‐release of chemokines, as IL‐6, IL‐1β and TNFα. These might have a pro‐vasodilation effect at a conjunctival level, with the clinical result of hyperaemia. Hyperaemia is hardly evaluable from a research point of view. The aim of this study is to investigate the use of conjunctival vessel density (CVD) as a marker of vessel dilation and, indirectly, of ocular surface inflammation, in a cohort of patients affected by autoimmune diseases. Methods: Study design: cross‐sectional, observational. CVD score was obtained analysing vessel‐enhanced images obtained by R‐scan module of Keratograph 5M (OCULUS Optikgeräte GmbH, Wetzlar, Germany). Images were loaded in ImageJ software package and in‐house scripts were used to analyse CVD at baseline and at follow‐up visit. CVD was obtained through the same methodology widely used in retinal research to study macular vessel density. Clinical data were collected and the correlations were reported. Results: We collected data from a cohort of patients suffering from autoimmune diseases. All the eyes were categorized considering both systemic and topic treatments, co‐existence of more autoimmune disorders, clinical signs and severity of dry eye. CVD values resulted significantly correlated with dry eye severity, in particular the higher was dry eye severity score, the higher was CVD (p < 0.05). Conclusions: CVD is a new quantitative metric to objectively measure conjunctival hyperaemia; this diagnostic methodology resulted highly feasible to be performed in clinical practice, without inducing patients' distress, and resulted a parameter highly correlated with the pro‐inflammatory status of the patients. Reference 1.Singh RB, Liu L, Anchouche S, Yung A, Mittal SK, Blanco T et al. Ocular redness ‐ I: Aetiology, pathogenesis, and assessment of conjunctival hyperemia. Ocul Surf 2021. 2. Wu S, Hong J, Tian L, Cui X, Sun X, Xu J. Assessment of Bulbar Redness with a Newly Developed Keratograph. Optom Vis Sci 2015. 3. Arrigo A, Aragona E, Saladino A, Amato A, Bandello F, Battaglia Parodi M. The impact of different thresholds on optical coherence tomography angiography images binarization and quantitative metrics. Sci Rep 2021. [ABSTRACT FROM AUTHOR]