Comparative analysis of iridian anterior segment OCT and microbiological features in Fuchs Uveitis Syndrome and Posner-Schlossman Syndrome.

Purpose: To compare iridian Swept-Source Anterior Segment OCT (SS-AS-OCT) and microbiological features in Aqueous Humor (AH) in patients with Fuchs Uveitis Syndrome (FUS) and Posner-Schlossman Syndrome (PSS).

Methods: Comparative, retrospective-prospective single center study examining 131 eyes from 66 patients, including 33 eyes with PSS, 37 eyes with FUS, and 61 healthy eyes. AH samples were collected from affected eyes in all patients. Cross-sectional 6 mm SS-AS-OCT B-scans were taken from iris quadrants and analyzed for Stromal Thickness (ST), Smooth Index (SI), and Optical Density (OD) with ImageJ®. Statistical analysis was performed using SPSS®.

Results: Among 32 PSS patients, Cytomegalovirus (CMV) was detected in 21 (65.5%). Of 34 FUS patients, 22 (64.7%) tested positive for Rubella Virus (RV) and one for CMV (2,9%). FUS eyes showed decreased ST compared to PSS ones in the superior (328.2 ± 49.4 vs 352.2 ± 47.4; p = 0.010) and temporal (322.6 ± 54.4 vs 294.3 ± 47.9; p = 0.024) quadrants. FUS eyes had a higher mean SI (p = 0.021), notably in the temporal quadrant (p = 0.002). Both FUS and PSS eyes showed significant differences in all parameters compared to healthy eyes, except for ST and OD in the temporal quadrant in PSS, and OD in the nasal quadrant in FUS. Quantitative analysis of iris OCT images showed that RV-related and non-RV-related FUS eyes were similar, as were CMV-associated and non-CMV-associated PSS eyes.

Conclusions: CMV and RV were found to be the main etiologies of PSS and FUS respectively. Quantitative analysis of iris OCT images has proved to be an objective method to differentiate between these two syndromes.

Key messages: What is known The etiopathogenesis of Fuchs Uveitis Syndrome (FUS) and Posner-Schlossman Syndrome (PSS) remains under discussion. Viral etiology is the most widely accepted theory: Rubella virus (RV) has been associated mostly with FUS and cytomegalovirus (CMV) with PSS. Although FUS and PSS are distinct conditions, their differential diagnosis can be challenging at times due to clinical similarities, particularly iris damage. What is new The quantitative analysis of iris images from Swept Source Anterior Segment OCT is an objective, reliable, and non-invasive method that allows differentiation between FUS and PSS. In this study, RV in FUS and CMV in PSS have been detected in almost 2/3 of patients. This is the first study to perform a comparative analysis of aqueous humor results between PSS and FUS along with the examination of iris images using SS-AS-OCT.