Optical Coherence Tomography Angiography in Diabetic Patients: A Systematic Review

Abstract

Background: Diabetic retinopathy (DR) is the leading cause of legal blindness in the working population in developed countries. Optical coherence tomography (OCT) angiography (OCTA) has risen as an essential tool in the diagnosis and control of diabetic patients, with and without DR, allowing visualisation of the retinal and choroidal microvasculature, their qualitative and quantitative changes, the progression of vascular disease, quantification of ischaemic areas, and the detection of preclinical changes. The aim of this article is to analyse the current applications of OCTA and provide an updated overview of them in the evaluation of DR. Methods: A systematic literature search was performed in PubMed and Embase, including the keywords “OCTA” OR “OCT angiography” OR “optical coherence tomography angiography” AND “diabetes” OR “diabetes mellitus” OR “diabetic retinopathy” OR “diabetic maculopathy” OR “diabetic macular oedema” OR “diabetic macular ischaemia”. Of the 1456 studies initially identified, 107 studies were screened after duplication, and those articles that did not meet the selection criteria were removed. Finally, after looking for missing data, we included 135 studies in this review. Results: We present the common and distinctive findings in the analysed papers after the literature search including the diagnostic use of OCTA in diabetes mellitus (DM) patients. We describe previous findings in retinal vascularization, including microaneurysms, foveal avascular zone (FAZ) changes in both size and morphology, changes in vascular perfusion, the appearance of retinal microvascular abnormalities or new vessels, and diabetic macular oedema (DME) and the use of deep learning technology applied to this disease. Conclusion: OCTA findings enable the diagnosis and follow-up of DM patients, including those with no detectable lesions with other devices. The evaluation of retinal and choroidal plexuses using OCTA is a fundamental tool for the diagnosis and prognosis of DR.

Retinal Vascularization Abnormalities Studied by Optical Coherence Tomography Angiography (OCTA) in Type 2 Diabetic Patients with Moderate Diabetic Retinopathy

“…Xiang et al and Nazir et al have demonstrated the ability of the technique to distinguish DR severity. In the near future, OCTA will help to conduct the DR progression assessment using AI [ 59 , 60 , 61 ].…”

Advances in Optical Coherence Tomography Imaging Technology and Techniques for Choroidal and Retinal Disorders

“…This technology was first introduced in 1991 [ 1 ] and has been rapidly adopted into clinical practice in retina. Diagnostic evaluation in retinal and choroidal diseases are often conducted with OCT, including neovascular age-related macular degeneration (AMD) [ 2 ], central serous chorioretinopathy (CSCR) [ 3 ], vascular retinal disorders [ 4 ], and other vitreoretinal disorders [ 5 ]. OCT biomarkers have also been instrumental in further understanding and monitoring chorioretinal disease status; these biomarkers include central macular thickness, subretinal/intraretinal fluid, neurosensory detachment height, subfoveal choroidal thickness, choroidal vessel diameter, and choroidal vascularity index [ 6 , 7 , 8 ].…”

Long‐term follow up of macular perfusion evaluated by optical coherence tomography angiography after rhegmatogenous retinal detachment surgery

“…2 of 14 OCT angiography (OCTA) is a non-invasive, dye-free procedure used to study the retinal capillary plexuses and choriocapillaris (CC) and is based only on the red cell movement inside the vessels [10]. Changes in the capillary vessels could serve as a marker of functional impairment and can correlate with the presence of photoreceptor or other neuron neurodegeneration, as has been described in other retinal diseases with vascular impairment [11]. However, microvascular modifications after RRD surgery are not welldescribed, and it is not clear if they are associated with unrecovered visual acuity (VA) in otherwise successful RRD surgeries without clear changes on OCT.…”

“…Both the fovea and the foveal slope lack retinal vessels; this area is known as the foveal avascular zone (FAZ) [12]. The FAZ varies in size and shape (acircularity index) across healthy subjects [13], in different retinal [11] or neurodegenerative diseases, [14][15][16][17] and in cardiovascular systemic pathology [18].…”