Diabetic Retinopathy Grading by Digital Curvelet Transform

Table 1

International clinical DR severity scale [5, 6].

Severity level	Findings observable
No DR	No abnormalities
Mild NPDR	This is the earliest stage of retinopathy and vision is usually normal except in some cases. Small swellings known as micro-aneurysms or flame-shaped hemorrhages start to develop in the fundus quadrants
Moderate NPDR	There will be micro-aneurysms or hemorrhages of greater severity in one to three quadrants and leakage might occur, resulting cotton wool spots and exudates and so fourth to be present in the retina
Severe NPDR	Any of the following: (i) Severe (more than 20) hemorrhages and MAs in all four quadrants of the fundus; (ii) Definite venous beading in at least two quadrants; (iii) Severe damage to the small blood vessels in at least one quadrant but no signs of any PDR
PDR	One or more of the following: Neovascularization; Vitreous/preretinal hemorrhage