optical coherence tomography angiography

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. Future studies may demonstrate how quantitative OCTA measures may have a role in detecting early retinal changes in patients with diabetes.ĭiabetes 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. OCTA may potentially serve as a useful non-invasive imaging tool in the diagnosis and monitoring of diabetic retinopathy and maculopathy in the future. Future applications of OCTA in the anterior segment include detection of anterior segment ischemia and iris neovascularisation associated with proliferative DR and risk of neovascular glaucoma. However, there are many limitations of OCTA in DR, such as difficulty in segmentation between superficial and deep capillary plexus and its use in diabetic macula edema where the presence of cystic spaces may affect image results. OCTA may also serve as a non-invasive imaging method to detect diabetic macula ischemia, which may help predict visual prognosis. These quantitative measures may be able to detect changes with the severity and progress of DR for clinical research. Recent studies on the role of OCTA in DR include the use of vascular parameters e.g., vessel density, intercapillary spacing, vessel diameter index, length of vessels based on skeletonised OCTA, the total length of vessels, vascular architecture and area of the foveal avascular zone. With the introduction of optical coherence tomography angiography (OCTA), it may serve as a potential rapid, non-invasive imaging modality as an adjunct. Currently, the standard imaging technique to monitor and prognosticate DR and diabetic maculopathy is dye-based angiography.

Diabetic retinopathy (DR) is a leading cause of vision loss in adults.

Optical coherence tomography angiography