Quantifying Retinal Microvascular Changes in Uveitis Using Spectral-Domain Optical Coherence Tomography Angiography

Abstract

Purpose To quantify retinal capillary density and morphology in uveitis using SD-OCTA. Design Cross-sectional, observational study Methods Healthy and uveitic subjects were recruited from two tertiary care eye centers. Prototype SD-OCTA devices (Cirrus, Carl Zeiss Meditec, Inc., Dublin, CA) were used to generate 3×3 mm2 OCTA images centered on the fovea. Subjects were placed into 3 groups based on the type of optical microangiography (OMAG) algorithm used for image processing (intensity-and/or phase) and type of retinal segmentation (automatic or manual). A semi-automated method was used to calculate skeleton density (SD), vessel density (VD), fractal dimension (FD), and vessel diameter index (VDI). Retinal vasculature was assessed in the superficial retinal layer (SRL), deep retinal layer (DRL), and non-segmented retinal layer (NS-RL). A generalized estimating equations model was used to analyze associations between the OCTA measures and disease status within each retinal layer. A P value < 0.05 was accepted as significant. Reproducibility and repeatability were assessed using the Intraclass Correlation Coefficient (ICC). Results The SD, VD, and FD of the parafoveal capillaries were lower in uveitic eyes compared to healthy eyes in all retinal segments. In addition, SD and VD were significantly lower in the DRL of subjects with uveitic macular edema. There was no correlation in any capillary parameters and anatomic classification of uveitis. Conclusions Quantitative analysis of parafoveal capillary density and morphology in uveitis demonstrates significantly lower capillary density and complexity. SD-OCTA algorithms are robust enough to detect these changes and can provide a novel diagnostic index of disease for uveitis subjects.

Radiation Maculopathy After Proton Beam Therapy for Uveal Melanoma: Optical Coherence Tomography Angiography Alterations Influencing Visual Acuity

“…Fractal dimension has previously been used to investigate the retinal microvasculature in fundus [49][50][51][52] or OCTA 10,12,13 images. By evaluating pattern repetition at different scales, 53 fractal dimension is particularly adapted to assess the integrity of arborized vascular networks.…”

“…Fractal dimension is a promising endpoint to measure vascular network disorganization in OCTA images, which has been used successfully in diabetic retinopathy [10][11][12] and posterior uveitis. 13 Ocular irradiation by I-125 plaque brachytherapy induces microvascular changes detected by OCTA. 14,15 However, the consequences of proton-beam therapy, a major treatment modality for uveal melanoma, have not been assessed by OCTA.…”

Quantitative microvascular analysis of retinal venous occlusions by spectral domain optical coherence tomography angiography

“…[13–15] These parameters are designed to quantitatively characterize capillary density (VD, SD) and capillary morphology (FD, VDI) since both density (“dropout”) and morphology (e.g. vessel dilation) are known variables in the development and progression of retinal vascular disease.…”

Repeatability, interocular correlation and agreement of quantitative swept-source optical coherence tomography angiography macular metrics in healthy subjects

“…Existing studies have reported enlarged foveal avascular zone (FAZ) area in retinal ischaemic diseases such as diabetic retinopathy (DR)10 and retinal vascular obstruction (RVO)11; decreased FAZ area in retinopathy of prematurity12; decreased vessel density in DR10 and glaucoma13; lower fractal dimension in RVO,11 DR10 and uveitis eyes14; increased vessel diameter index (VDI) in RVO11 and DR10; and decreased FAZ circularity in glaucoma15 and DR 10. These studies demonstrate that quantitative OCTA metrics may provide useful information for the diagnosis of ocular diseases potentially.…”