Regular Chinese Green Tea Consumption Is Protective for Diabetic Retinopathy: A Clinic-Based Case-Control Study

Table 1

Grading schemes of diabetic retinopathy.

Severity of diabetic retinopathy	Grading schemes
Minimal nonproliferative diabetic retinopathy (NPDR)	Level 15 through 20
Mild NPDR	Level 35
Moderate NPDR	Level 43 through 47
Severe NPDR	Level 53
Proliferative diabetic retinopathy (PDR)	Level more than 60
Macular edema	Hard exudates in the presence of microaneurysms and blot hemorrhage with one disc diameter from the foveal center or presence of focal photocoagulation scars in the macular areas.
Clinically significant macular edema (CSME)	Macular edema within 550 m of the foveal center or if focal photocoagulation scars were present in the macular area.
Sight-threatening retinopathy (STDR)	Severe NPDR, PDR, or CSME.