Diabetes causes problems in the retina with what are collectively called microvascular abnormalities. The small blood vessels develop microaneurysms and leak blood. New blood vessel growth (neovascularization) occurs. Unfortunately, these blood vessels are weak and also leak. These leaks (hemorrhages) can cause irreversible damage to the retina and permanent vision loss.
Patients with controlled diabetes do better than those with uncontrolled diabetes. However, even a person whose diabetes is under perfect control can still develop diabetic retinopathy — hence, the need for yearly retinal exams.
Diabetic retinopathy — vision-threatening damage to the retina of the eye caused by diabetes — is the leading cause of blindness among working-age Americans.
The good news: Diabetic retinopathy often can be prevented with early detection, proper management of your diabetes and routine eye exams performed by your optometrist or ophthalmologist.
According to the International Diabetes Federation (IDF), the United States has the highest rate of diabetes among 38 developed nations, with approximately 30 million Americans — roughly 11 percent of the U.S. population between the ages of 20 and 79 — having the disease.
Generally, diabetics don't develop diabetic retinopathy until they have had diabetes for at least 10 years. But it is unwise to wait that long for an eye exam.
With any diagnosis of diabetes, your primary care physician should refer you to an eye doctor (optometrist or ophthalmologist) for a dilated eye exam at least once a year.
How Does Diabetes Cause Diabetic Retinopathy?
Diabetes mellitus (DM) causes abnormal changes in the blood sugar (glucose) that your body ordinarily converts into energy to fuel different bodily functions.
Uncontrolled diabetes allows unusually high levels of blood sugar (hyperglycemia) to accumulate in blood vessels, causing damage that hampers or alters blood flow to your body's organs — including your eyes.
Diabetes generally is classified as two types:
· Type 1 diabetes. Insulin is a natural hormone that helps regulate the levels of blood sugar needed to help "feed" your body. When you are diagnosed with type 1 diabetes, you are considered insulin-dependent because you will need injections or other medications to supply the insulin your body is unable to produce on its own. When you don't produce enough of your own insulin, your blood sugar is unregulated and levels are too high.
· Type 2 diabetes. When you are diagnosed with type 2 diabetes, you generally are considered non-insulin-dependent or insulin-resistant. With this type of diabetes, you produce enough insulin but your body is unable to make proper use of it. Your body then compensates by producing even more insulin, which can cause an accompanying abnormal increase in blood sugar levels.
With both types of diabetes, abnormal spikes in blood sugar increase your risk of diabetic retinopathy.
Eye damage occurs when chronically high amounts of blood sugar begin to clog or damage blood vessels within the eye's retina, which contains light-sensitive cells (photoreceptors) necessary for good vision.
Symptoms Of Diabetic Retinopathy And Other Diabetes-Related Eye Problems
You first may notice diabetic retinopathy (DR) or other eye problems related to diabetes when you have symptoms such as:
Eye floaters and spots
Development of a scotoma or shadow in your field of view
Blurry and/or distorted vision
Corneal abnormalities such as slow healing of wounds due to corneal abrasions
Near vision problems unrelated to presbyopia
During an eye examination, your eye doctor will look for other signs of diabetic retinopathy and diabetic eye disease. Signs of eye damage found in the retina can include swelling, deposits and evidence of bleeding or leakage of fluids from blood vessels.
Your eye doctor will use a special camera or other imaging device to photograph the retina and look for telltale signs of diabetes-related damage. In some cases, he or she may refer you to a retinal specialist for additional testing and possible treatment.
For a definitive diagnosis, you may need to undergo a test called a fluorescein angiography. In this test, a dye is injected into your arm intravenously and gradually appears in the blood vessels of the retina, where it is illuminated to detect diabetes-related blood vessel changes and blood leakage in the retina.
One sometimes overlooked symptom of diabetic eye disease is nerve damage (neuropathy) affecting ocular muscles that control eye movements. Symptoms can include involuntary eye movement (nystagmus) and double vision.
Source: All About Vision.