Diabetic Retinopathy
Introduction
Diabetic retinopathy is a complication of diabetes that affects vision. It is the leading cause of blindness in Americans under the age of 65 and currently the leading cause of new cases of legal blindness. The key to diabetic retinopathy is early detection by eye examinations and control of blood glucose and blood pressure to reduce the risk of development and progression.
What is Diabetes?
Diabetes mellitus is a metabolic abnormality that affects the way the body uses sugar (glucose). There are two major categories of diabetes: type I (juvenile onset) and type II (adult onset). Type I diabetes usually develops early in life and can lead to complications like diabetic retinopathy after several years. Type II diabetes may exist for many years before being diagnosed, and in some cases, retinopathy is found before diabetes itself.
What causes diabetic complications?
Complications of diabetes occur when high blood sugar damages small blood vessels in the eyes, kidneys, nerves, heart, and other organs. This damage, known as microangiopathy, is directly linked to prolonged high blood sugar. Good control of blood sugar, blood pressure, and cholesterol is essential to prevent these problems. Discuss your care plan with your physician to keep your diabetes under control.
How can I keep from going blind?
Strong diabetic control is key to preventing blindness. Chronically elevated blood sugar damages blood vessels, leading to retinopathy, kidney disease, heart disease, and strokes. Advances in diabetic care, including new medications, insulin pumps, and glucose monitoring technology, can help maintain good control and reduce the risk of blindness.
How do I know if I’m in good control?
The best test to evaluate diabetic control is the Glycated Hemoglobin (A1C) test. Diabetes can affect several parts of the eye, including the lens (cataract), retina (diabetic retinopathy), eye pressure (glaucoma), and optic nerve (optic neuropathy). These conditions can also occur in non-diabetic patients but are more common and more severe in people with diabetes.
How does diabetes affect the eye and vision?
The eye works like a camera. Light passes through the cornea and lens and is focused on the retina at the back of the eye. The retina processes images and sends signals to the brain through the optic nerve. Diabetes can damage the retina’s blood vessels, leading to retinopathy, and can also cause cataracts, glaucoma, or optic nerve problems. Proper control of blood sugar helps reduce the risk of these issues.
What is diabetic retinopathy?
The retina is a thin layer of tissue that lines the back of the eye. Over time, high blood sugar can damage its blood vessels, leading to diabetic retinopathy. It can be classified as non-proliferative (background) or proliferative retinopathy. Vision loss may occur in both forms due to macular edema, where the macula swells and vision decreases. Areas of poor circulation (ischemia) can also form, appearing as white spots known as cotton-wool spots.
Evaluation involves a retinal exam and tests such as fluorescein angiography and OCT (Optical Coherence Tomography) to detect swelling or circulation problems.
Classification of diabetic retinopathy:
Mild background retinopathy: The earliest stage, showing small vessel changes and hemorrhages. Better blood sugar control at this stage can prevent progression.
Moderate background retinopathy: More advanced changes with vessel blockages, hemorrhages, and yellow deposits (exudates). Blood pressure and cholesterol control are vital to prevent further damage.
Severe or pre-proliferative retinopathy: A more advanced stage with widespread damage and higher risk of progression to proliferative retinopathy. Laser treatment may be needed to prevent vision loss.
Proliferative retinopathy: The most advanced stage, with new blood vessels growing in the eye that can bleed or cause retinal detachment. Laser photocoagulation and anti-VEGF injections can reduce the risk of blindness.
Macular Edema
Swelling of the macula is the most common cause of vision loss in diabetes. It can occur at any stage and is treated with laser therapy or eye injections.
Treatments
Modern treatments include anti-VEGF injections (Lucentis, Eylea, Vabysmo, or Avastin), steroids, and laser procedures. These treatments can improve or stabilize vision in many patients. In some advanced cases, vitrectomy surgery is needed to remove blood and scar tissue to restore sight.
What is a cataract and should I have it removed?
A cataract is clouding of the lens of the eye. Cataracts are common in diabetics and can be treated with surgery. However, good blood sugar control and an eye exam before surgery are important to avoid swelling or complications after the procedure.
What is neovascular (rubeotic) glaucoma?
In advanced diabetes, new blood vessels can grow and block fluid drainage in the eye, raising pressure and damaging the optic nerve. Laser treatments and injections can help shrink these vessels and lower eye pressure.
What is optic neuropathy?
Optic neuropathy occurs when blood flow to the optic nerve is reduced. This can cause permanent vision loss, and currently there is no effective treatment for diabetic ischemic optic neuropathy.
Will I go blind?
With good diabetic control, regular exams, and timely treatment, most people with diabetes do not lose their vision. Early care and ongoing monitoring by a retinal specialist can prevent blindness.