Stages of Diabetic Retinopathy
The two most important visual complications of diabetic retinopathy are proliferative diabetic retinopathy (PDR) and Diabetic Macular edema (DME)
Diabetic retinopathy occurs in two main stages, and their following visual complications consist of DME and PDR.
Stage 1: Mild Nonproliferative retinopathy
At the first stage there are microaneurysms in the retinal blood vessels. The blood vessels surrounding the retina will swell and accumulate fluid. It is referred to as Mild Nonproliferative retinopathy. Due to diabetic complications such as hyperglycemia, the pericytes, the small blood vessels in the retina will burst because they are more likely to have poor blood glucose control. As the disease progresses, the nourishing blood vessels of the retina are blocked. Then finally as more retinal blood vessels are being damaged, there is a signal to form more blood vessels and this is when the disease enters the proliferation stage.
Stage 2:Proliferative Retinopathy
As the signals for more blood vessels are triggered, the disease enters the proliferative stage. The new blood vessels tend to accumulate closer to the vitreous humor and due to their delicate nature and improper respiration are in turn apt to rupture and bleed into the humor. This will cause a blurring in the vision until the humor is ultimately filled with blood resulting in total vision loss. However, since it is initially only presented through initial blurriness it can be possible to prevent further deterioration.
The figure is a moderate stage proliferative retinopathy, which can be seen by the prevalence of large aneurysms and clouding in the retina.
Macular Edema also occurs in approximately 40-50% of diabetic retinopathic patients. Fluids and proteins can accumulate in,on and around the macula, the main focusing area of the retina. The macula is responsible for allowing us to see sharply focused, straight line vision. As the fluids and protein deposits accumulate the macula becomes thicker and swells.
As a risk of severe oxygen deprivation in the eye due to the complications of the proliferative retinopathy and the macular edema, a small population of individuals can develop neovascular glaucoma from the anaerobic conditions in the eye. As the figure represents, macular edema can be detected by the accumulations of protein debris and fluids surrounding the center of the retina which is important for straight line vision.