Diagnosis
3
Table 1. Diabetic Retinopathy Disease Severity Scale and
International Clinical Diabetic Retinopathy Disease
Severity Scale
Disease Severity Level
Findings Observable Upon Dilated
Ophthalmoscopy
No apparent retinopathy No abnormalities
Mild NPDR Microaneurysms only
Moderate NPDR More than just microaneurysms but less than severe
NPDR
Severe NPDR
U.S. Definition
Any of the following (4-2-1 rule) and no signs of
proliferative retinopathy:
• Severe intraretinal hemorrhages and
microaneurysms in each of four quadrants
• Definite venous beading in two or more quadrants
• Moderate IRMA in one or more quadrants
International Definition Any of the following and no signs of proliferative
retinopathy:
• >20 intraretinal hemorrhages in each of four
quadrants
• Definite venous beading in two or more quadrants
• Prominent IRMA in one or more quadrants
PDR One or both of the following :
• Neovascularization
• Vitreous/preretinal hemorrhage
IRMA, intraretinal microvascular abnormalities; NPDR, nonproliferative diabetic
retinopathy; PDR, proliferative diabetic retinopathy
Note:
• Any patient with two or more of the characteristics of severe NPDR is considered to have
very severe NPDR.
• PDR may be classified as high-risk and non-high-risk. See Table 8 for more information.
Adapted with permission from Wilkinson CP, Ferris FL III, Klein RE, et al. Proposed international
clinical diabetic retinopathy and diabetic macular edema disease severity scales. Ophthalmolog y
2003;110:1679.
