optical coherence tomography angiography

The number of patients vary widely among studies. In total, there were two multi-centred studies. There was a total of 19 retrospective studies, of which 12 were observational, two were observational cross-sectional, two were case-control and three were cross-sectional. There was a total of 58 prospective studies, of which 17 were observational, 30 were observational and cross-sectional, and 11 were observational case-control study. Eighty-eight articles were identified, with 11 papers being excluded as they were either reviews, inter-instrumental reliability study or case report/series. All papers that used OCTA were reviewed for findings in DR and bibliographies were hand-searched for further studies. We conducted a literature search via PUBMED database for articles written in the English language until January 1, 2019, with the following medical subject headings: “OCTA,” “OCT angiography,” “Diabetic Retinopathy,” or “Diabetes”. In this review, we will discuss the role of OCTA in the evaluation and monitoring of DR, diabetic maculopathy and the anterior segment involvement in DR.

It allows depth-resolved imaging of the retinal vasculature and is an ideal approach for various retinal conditions such as DR, retinal venous occlusion, uveitis, retinal arterial occlusion and age-related macular degeneration. This is performed through repeated scans at the same location to detect the changes in OCT reflectance signal from the flow through blood vessels. Optical coherence tomography angiography (OCTA) is a novel use of OCT to visualise the microvasculature of the retina and choroid without the need for dye injection. Optical Coherence Tomography (OCT) offers a non-invasive, rapid imaging modality that can provide imaging of the cross-sectional structures of the retina by using low-coherence interferometry to capture high resolution two dimensional images from the optical scattering from different layers of the retina and is an essential tool in the detection and monitoring of DME, and DMI with inner retinal thinning. While it has high sensitivity and specificity, it has been shown to have a low negative predictive value. Digital retinal fundus image analysis has been shown to be able to detect early DR and DME in routine DR screening. The main sight-threatening complications of DR are diabetic maculopathy, which include diabetic macular oedema (DME) and diabetic macular ischemia (DMI), and complications from PDR - vitreous haemorrhage and retinal detachment. Diagnosis of DR is based on clinical findings and can be divided into 2 categories - early non-proliferative diabetic retinopathy (NPDR) and more advanced proliferative diabetic retinopathy (PDR) associated with retinal ischemia and development of neovascularisation. Diabetic retinopathy is a leading cause of blindness in working age adults and is estimated to affect 1 in 3 diabetic patients.

The most common ocular complication is diabetic retinopathy (DR), which may be asymptomatic in the early stages, however, disease progression can lead to severe vision loss.

Diabetes is currently on the rise with 422 million of people in the world reported to have diabetes in 2014 and is a systemic disease with a multitude of complications which may involve the eyes.