Traditionally, abnormalities of the retinal vasculature and perfusion in retinal vascular disorders, such as diabetic retinopathy and retinal vascular occlusions, have been visualized with dye-based fluorescein angiography (FA). Optical coherence tomography angiography (OCTA) is a newer, alternative modality for imaging the retinal vasculature, which has some advantages over FA, such as its dye-free, non-invasive nature, and depth resolution. The depth resolution of OCTA allows for characterization of the retinal microvasculature in distinct anatomic layers, and commercial OCTA platforms also provide automated quantitative vascular and perfusion metrics. Quantitative and qualitative OCTA analysis in various retinal vascular disorders has facilitated the detection of pre-clinical vascular changes, greater understanding of known clinical signs, and the development of imaging biomarkers to prognosticate and guide treatment. With further technological improvements, such as a greater field of view and better image quality processing algorithms, it is likely that OCTA will play an integral role in the study and management of retinal vascular disorders. Artificial intelligence methods—in particular, deep learning—show promise in refining the insights to be gained from the use of OCTA in retinal vascular disorders. This review aims to summarize the current literature on this imaging modality in relation to common retinal vascular disorders.

This review provides an overview of conventional and novel retinal imaging modalities for hydroxychloroquine (HCQ) retinopathy. HCQ retinopathy is a form of toxic retinopathy resulting from HCQ use for a variety of autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus. Each imaging modality detects a different aspect of HCQ retinopathy and shows a unique complement of structural changes. Conventionally, spectral-domain optical coherence tomography (SD-OCT), which shows loss or attenuation of the outer retina and/or retinal pigment epithelium–Bruch’s membrane complex, and fundus autofluorescence (FAF), which shows parafoveal or pericentral abnormalities, are used to assess HCQ retinopathy. Additionally, several variations of OCT (retinal and choroidal thickness measurements, choroidal vascularity index, widefield OCT, en face imaging, minimum intensity analysis, and artificial intelligence techniques) and FAF techniques (quantitative FAF, near-infrared FAF, fluorescence lifetime imaging ophthalmoscopy, and widefield FAF) have been applied to assess HCQ retinopathy. Other novel retinal imaging techniques that are being studied for early detection of HCQ retinopathy include OCT angiography, multicolour imaging, adaptive optics, and retromode imaging, although further testing is required for validation.

Purpose: To characterize and evaluate differences in fundus autofluorescence (FAF) alteration in polypoidal choroidal vasculopathy (PCV) and typical neovascular age-related macular degeneration (tAMD). Methods: The authors used multimodal imaging to delineate the area of macular neovascularization (MNV) and extent of subretinal fluid (SRF). Macular FAF alteration was categorized to those limited to the area of the neovascular lesion (Zone 1), area beyond Zone 1 affected by subretinal fluid or pigment epithelial detachment (Zone 2), and area beyond Zone 2 (Zone 3). Loss of FAF signal that correlated with complete outer retina and RPE loss (c-RORA) was documented. Results: The authors included 94 eyes from 94 patients (48 with diagnosis of PCV; 46 with diagnosis of tAMD). The PCV eyes had greater subfoveal choroidal thickness (250 ± 92 vs. 178 ± 86 µm, P < 0.001) compared with tAMD. FAF alteration was seen in all eyes in Zone 1 and 2. Polypoidal lesion(s) appear as hyper-AF, iso-AF, or hypo-AF round lesions. The FAF alteration extending to Zone 3 was observed in 41.7% of PCV eyes and 19.6% of tAMD eyes (P = 0.02), in which hyper-AF pattern was predominant. Furthermore, Zone 3 FAF alteration was associated with choroidal vascular hyperpermeability in eyes with PCV but not in tAMD (40% vs. 0%, P = 0.03). Conclusion: These findings highlight that retinal pigment epithelium dysfunction may affect widespread areas in PCV and may be the effect of choroidal congestion.