Diabetic retinopathy is a complication of diabetes in which the back part of the eye called the retina is damaged. Small blood vessels are very susceptible to the damage that can be caused by high blood glucose levels (hyperglycemia) and your eyes have very tiny blood vessels. Your eyes also require a lot of blood and oxygen, and smaller blood vessels affected by diabetes can weaken, causing them to develop balloon-like swellings called microaneurysms (also called microvascular abnormalities) that can leak or even burst. When the walls of the blood vessels supplying your retina are damaged by an over accumulation of glucose and leak it causes a disruption in the flow of oxygen and nourishment to tissues supplied by them, which can lead to the damage or death of those tissues. Damaged blood vessels are eventually replaced by new blood vessel growth (neovascularization), but these are weaker and can also leak.
The damage from hyperglycemia is only the start, the real damage occurs from the lack of oxygen to the retina as a result, causing irreversible damage to the retina leading to impaired vision or blindness. Sight is not only one of most important senses a person possesses, it is also one of the most rewarding. Just consider all of the wonderful and beautiful things vision brings into your life on a daily basis...and then imagine one day losing your ability to enjoy such sights as a beautiful sunrise, sunset or even seeing the faces of your loved ones. Unfortunately for millions of people around the world that has, or is well on its way of happening due to diabetic retinopathy, and a person that has diabetes is four times more likely to suffer vision loss than someone who does not. Diabetes is the number one cause of blindness in the United States among adults aged 20 to 74 years of age accounting for about 24,000 new cases every year.
First stage of diabetic retinopathy - Abnormalities appear that are mild and non-spreading. Characterized by an increase in the blood vessel's permeability (porousness).
Second stage of diabetic retinopathy - Abnormalities appear that are moderate to severe and non-spreading. Characterized by closed blood vessels. Also known as Nonproliferative Diabetic Retinopathy (NPDR).
Third stage of diabetic retinopathy - The third stage is known as Proliferative Diabetic Retinopathy (PDR). Which is characterized by new growth of blood vessels on the retina and rear surface of the "vitreous chamber" of the eye. The Macula is the area located near the center of the retina, and is where visual perception is most acute. Macular edema is an eye disease that is characterized by a thickening or swelling of the retina caused by leaking blood vessels and can occur at any stage of retinopathy.
In the case of Type 1 patients it is rare for them to develop retinopathy severe enough to threaten their vision in the years before puberty or in the first three to five years after they are first diagnosed, however nearly all will have developed it to some degree by the time they reach their thirties. It has been estimated that roughly twenty one percent of people that have type 2 diabetes will have diabetic retinopathy by the time they are first diagnosed and most will develop it to some degree over time. Diabetic retinopathy also increases a person's chances of developing cataracts and glaucoma. Another concern for diabetic patients where vision is concerned is that of "autonomic neuropathy" which can affect the nerves in the eyes.