Vitreoretinal Interface Cells Correlate In Vivo With Uveitis Activity and Decrease With Anti-Inflammatory Treatment.

Purpose: To highlight the utility of en face swept-source optical coherence tomography angiography (SS-OCTA) in assessing vitreoretinal interface cells (VRICs) of patients with active uveitis and their dynamics. Methods: In this prospective, single-center study, 20 eyes from patients with active uveitis were analyzed using six 6 × 6-mm macular scans at three time points: active inflammation (baseline), clinically improving (T1), and resolved inflammation (T2). VRICs were visualized using 3-µm en face OCT slabs on the inner limiting membrane. The variation of VRIC number, density, and size over time was assessed, and VRIC measurements were compared with clinical grading. Results: At baseline, the VRIC count was significantly higher (552.5 VRICs) than that of the healthy controls (478.2 VRICs), with a density of 15.3 cells/mm2. VRIC number decreased significantly to 394.8 (P = 0.007) at T1, with a density of 10.9 cells/mm2 (P = 0.007). VRIC size reduced from 6.8 µm to 6.3 µm at T1 (P = 0.009) and remained stable at T2 (P = 0.3). Correlation coefficients between inflammatory parameters (anterior chamber cells and National Eye Institute vitreous haze), and VRIC count indicated a positive correlation at baseline (r = 0.53), weakening at T1 (r = 0.36), and becoming negative at T2 (r = -0.24). Conclusions: En face SS-OCTA revealed increased VRIC number and size in active uveitis, likely due to monocyte recruitment. Post-inflammation control, VRIC number, size, and density significantly decreased, returning to normal despite residual anterior chamber cells or vitreous haze. Translational Relevance: Visualization of VRICs by in vivo OCT opens up new opportunities for therapeutic targets.

Automated quantification of uveitic keratic precipitates by use of anterior segment optical coherence tomography.

BACKGROUND: Evaluation of ocular inflammation via common imaging modalities like optical coherence tomography (OCT) has emphasised cell visualisation, but automated detection of uveitic keratic precipitates (KPs) remains unexplored. METHODS: Anterior segment (AS)-OCT dense volumes of the corneas of patients with uveitic KPs were collected at three timepoints: with active (T0), clinically improving (T1), and resolved (T2) inflammation. At each visit, visual acuity and clinical grading of the anterior chamber cells were assessed. A bespoke algorithm was used to create an en face rendering of the KPs and to calculate their volume and a ratio of the volume of precipitates over the analysed area. The variation of AS-OCT-derived measurements over time was assessed, and compared with clinical grading. RESULTS: Twenty eyes from 20 patients (13 females, mean age 39 years) were studied. At T0, the mean volume of the corneal KPs was 0.1727 mm3 , and it significantly reduced to 0.1111 mm3 (p = 0.03) only at T2. The ratio between the volume of the KPs and the corneal area decreased from T0 (0.007) to T1 (0.006; p = 0.2) and T2 (0.004; p = 0.009). There was a statistically significant correlation between the AC cell count and the AS-OCT volume measurements of the KPs at the three time points. CONCLUSIONS: AS-OCT can image uveitic KPs and through a bespoke algorithm we were able to create an en face rendering allowing us to extrapolate their volume. We found that objective quantification of KPs correlated with inflammatory cell counts in the anterior chamber.

In Vivo Visualization of Macrophage-Like Cells in Patients with Uveitis by Use of En Face Swept Source Optical Coherence Tomography.

AIMS: To detect macrophage-like cells (MLCs) in uveitis patients and describe their characteristics compared to healthy subjects by using en face SS-OCTA. METHODS: Fifteen consecutive patients with "active" uveitis and 11 healthy participants underwent 6 macular scans of 6×6mm using SS-OCTA. The 3µm en face OCT slabs on inner limiting membrane were used to visualize the MLCs. RESULTS: In healthy subjects there was an average of 478.2±149.7 MLCs with a density of 13.28±4.16 cells/mm2. MLCs were larger in patients with "active" uveitis than in controls (891.18±69.46 µm2 vs.885±77.53 µm2). Patients with "active" anterior uveitis had a significantly reduced count and density of MLCs (172±14.68 and 4.77±0.4 cell/mm2) compared to controls, while patients with posterior uveitis had a statistically increased count (546.1±132.4) and area (909.23+/-54.97 µm2) of MLCs compared to controls. CONCLUSIONS: MLCs detected with en face SS-OCTA are increased in number and size in active posterior uveitis eyes compared to controls.