This study has suggested that arterial hypertension history was a independent risk factor for DR, it was the same with Australia [21], which would be because that hypertension was a risk factor for DR [22] and many diabetic always had hypotension, the renin-angiotensin system was activated by chronic hyperglycemia, and then the vitreous fluid level of angiotensin II (AII) was elevated in patients with PDR and diabetic macular edema. The gene discussed is REN; the disease is diabetic macular edema.