At first, diabetic retinopathy may cause no symptoms or only mild vision problems. Eventually, it can cause blindness.

The condition can develop in anyone who has type 1 or type 2 diabetes. The longer you have diabetes and the less controlled your blood sugar is, the more likely you are to develop this eye complication.

The development and progression of DR is primarily caused by the tissue-damaging effects of chronic hyperglycemia that results in a complex interplay of multiple mechanisms , which cause two basic changes within the retinal vessels, namely: abnormal permeability, and occlusion with ischemia and subsequent neovascularization. ¹

●Biochemical pathways (glycation, protein kinase C, and polyol pathways) and changes in retinal blood flow are particularly important during early disease, even before the development of microaneurysms or other clinically visible findings.

●Angiogenesis factors such as vascular endothelial growth factor (VEGF) and insulin-like growth factor 1 (IGF-1) are more likely to be important later in the course of the disease, immediately prior to and during the development of proliferative DR or diabetic macular edema.

Differences in genetic susceptibility to the effects of hyperglycemia in the retina may exist among people at different stages of diabetic disease. This could result in inter- and intra-individual variations in biochemical or physiologic responses to hyperglycemia and may exist among people at different stages of diabetic disease. This variability may explain why a few patients with diabetes have minimal retinopathy despite years of severe hyperglycemia, whereas in others, severe retinopathy develops in a short period despite relatively good glycemic control.

Content 7