Vessel density on optical coherence tomography angiography is prognostic for future disease course in intermediate uveitis.

As most rare diseases, intermediate uveitis lacks reliable endpoints necessary for randomized clinical trials. Therefore, we investigated longitudinal changes of retinal and choriocapillaris perfusion on optical coherence tomography angiography (OCT-A) in intermediate uveitis and their prognostic value for future best corrected visual acuity (BCVA) and central retinal thickness (CRT). In this retrospective, longitudinal cohort study eyes of patients with intermediate uveitis were imaged by swept-source OCT-A (macula-centered 3 × 3 mm; PLEX Elite 9000, Zeiss) and stratified into clinically stable, worsened and improved based on changes in clinical parameters. Superficial (SRL) and deep retinal layers (DRL) were automatically analyzed for vessel density (VD) and choriocapillaris layer for non-perfused area (CCNPA) using ImageJ. Mixed-effects regression analysis controlling for age, sex, and OCT-A signal strength index (SSI) was used to evaluate the prognostic value of OCT-A parameters. 91 eyes (62 stable, 12 worsened, and 17 improved) were included in the analysis and mean follow-up time was 296 days. Longitudinal changes of VD were different between all three groups (p = 0.002 for SRL and p = 0.017 for DRL). Clinically worsened eyes showed a decrease in VD (- 0.032 ± 0.055 for SRL and - 0.027 ± 0.025 for DRL), whereas clinically improved eyes showed an increase in VD (0.037 ± 0.039 for SRL and 0.001 ± 0.023 for DRL). No difference was found for CCNPA. When controlling for age, sex, and SSI, observed differences held true in clinically worsened eyes for DRL (p = 0.011) and in clinically improved eyes for SRL (p = 0.002). An increase of CCNPA in clinically worsened eyes (p = 0.03) compared to clinically stable and improved eyes was evident. Predictive analysis revealed an association of VD in SRL and DRL at baseline with BCVA at follow-up (p = 0.039 and p = 0.047, respectively) and of VD in SRL at baseline with CRT at follow-up (p = 0.046). Alterations in retinal perfusion on OCT-A in intermediate uveitis are partly reversible and OCT-A VD may serve to predict future BCVA and CRT. Thus, perfusion parameters on OCT-A might aid monitoring and serve as prognostic imaging-biomarker.

Spectrally resolved autofluorescence imaging in posterior uveitis.

Clinical discrimination of posterior uveitis entities remains a challenge. This exploratory, cross-sectional study investigated the green (GEFC) and red emission fluorescent components (REFC) of retinal and choroidal lesions in posterior uveitis to facilitate discrimination of the different entities. Eyes were imaged by color fundus photography, spectrally resolved fundus autofluorescence (Color-FAF) and optical coherence tomography. Retinal/choroidal lesions' intensities of GEFC (500-560 nm) and REFC (560-700 nm) were determined, and intensity-normalized Color-FAF images were compared for birdshot chorioretinopathy, ocular sarcoidosis, acute posterior multifocal placoid pigment epitheliopathy (APMPPE), and punctate inner choroidopathy (PIC). Multivariable regression analyses were performed to reveal possible confounders. 76 eyes of 45 patients were included with a total of 845 lesions. Mean GEFC/REFC ratios were 0.82 ± 0.10, 0.92 ± 0.11, 0.86 ± 0.10, and 1.09 ± 0.19 for birdshot chorioretinopathy, sarcoidosis, APMPPE, and PIC lesions, respectively, and were significantly different in repeated measures ANOVA (p < 0.0001). Non-pigmented retinal/choroidal lesions, macular neovascularizations, and fundus areas of choroidal thinning featured predominantly GEFC, and pigmented retinal lesions predominantly REFC. Color-FAF imaging revealed involvement of both, short- and long-wavelength emission fluorophores in posterior uveitis. The GEFC/REFC ratio of retinal and choroidal lesions was significantly different between distinct subgroups. Hence, this novel imaging biomarker could aid diagnosis and differentiation of posterior uveitis entities.