Diabetic Retinopathy: From Clinical Investigation to Fractal Analysis of OCTA Images

Retinal blood vessels form a complex branching pattern that has been shown to be fractal. Since the retinal blood vessels grow through the diffusion of angiogenic factors within the retinal plane, the Fractal Dimension (FD) of the vascular network lies between 1 and 2: This means that the branching pattern fills space more than a line, but less than a plane. In healthy human subjects, the retinal FD has been reported to be approximately 1.7, but it can be altered by the rarefaction or proliferation of blood vessels under pathological conditions. We consider Diabetic Retinopathy (DR), a retinal microvascular complication of diabetes mellitus, associated with chronic hyperglycemia. The aim of this paper is to analyze the fractal dimensions of the superficial and deep retinal vascular plexuses in Optical Coherence Tomography Angiography (OCTA) images. This could help ophthalmologists to make an early diagnosis of this pathology and reduce the risk of severe retinal complications and vision loss.