Half of all people with diabetes develop diabetic retinopathy — a complication of the retina that can cause blurred or double vision — at some point. Generally the longer a person has the disease, and the less controlled their blood sugar is, the greater their chances of developing diabetic retinopathy. If left untreated, diabetic retinopathy can lead to irreversible vision loss.
With modern diagnosis and treatment methods, only a small number of people with retinopathy currently suffer serious vision problems. Seeing a retina specialist (an ophthalmologist with advanced training in disorders of the retina and vitreous) is crucial to detect the disease early and take preventive steps to avoid vision loss and blindness.
What Causes Diabetic Retinopathy?
People with diabetes have problems with the amount of glucose (sugar) in their blood. When the blood sugar levels are elevated for a prolonged period of time, it can damage the network of small blood vessels that nourish the retina.
There are two types of diabetic retinopathy. The earlier form, called nonproliferative diabetic retinopathy, causes mild symptoms (or no symptoms at all). The more advanced form is called proliferative diabetic retinopathy.
In nonproliferative diabetic retinopathy, the blood vessels in the retina weaken and start to leak fluid and blood. Microaneurysms, or tiny bulges in the blood vessels, can leak fluid into the retina. Other changes can occur, too. For example, the central portion of the retina called the macula can start to swell or thicken. This is known as macular edema, and is the leading cause of vision loss in people with diabetes.
In proliferative diabetic retinopathy, many of the blood vessels in the retina close, depriving the retina of oxygen. To compensate, the retina grows new blood vessels, but the blood vessels are abnormal and do not supply the retina with the blood supply or oxygen that it needs. They may leak into the vitreous, the clear gel-like substance that fills the center of the eye. The retina can also develop scar tissue, which may cause the retina to wrinkle or start to detach from the back of the eye. The abnormal blood vessels may also interfere from the normal tear drainage system, causing pressure to build. Eventually, this has the potential to damage the optic nerve and lead to glaucoma.
Symptoms of diabetic retinopathy include:
- Blurred vision
- Double vision
- Difficulty reading
- Dark areas of vision
- Floaters (visual disturbances that look like spots or specks)
- Pain or pressure in the eye
- Partial or total loss of vision
Diabetic retinopathy sometimes lacks symptoms, especially in its early stages. As the disease progresses, visual symptoms start to appear and worsen. If it advances to retinal tear or detachment, symptoms can be severe.
Diagnosing Diabetic Retinopathy
Diabetic retinopathy is diagnosed during a comprehensive eye exam with an ophthalmologist or a retina specialist. Visual acuity is tested and the eyes are dilated to give the doctor a close look at the internal structures. During diagnosis the doctor looks for the following:
- New blood vessels
- Abnormal blood vessels
- Scar tissue
- Swelling, blood or fatty deposits in the retina
- Irregularities in the optic nerve
- Signs of retinal detachment
The doctor may also perform a fluorescein angiography test. A special dye is injected into the arm, which circulates through the eyes. As it circulates, the doctor takes photos of the retina, looking for any blood vessels that are closed, damaged or leaking.
An optical coherence tomography test shows cross-sectional images of the retina to help the doctor determine whether fluid has leaked into the retinal tissues. If the tests detect signs of diabetic retinopathy, future OCT tests can be performed to monitor the effectiveness of treatment.
Once diabetic retinopathy diagnosis is confirmed, the doctor outlines treatment options and offers recommendations for the most appropriate way to proceed.
Worried about Your Eye Health?
If you are living with diabetes and would like to stay on top of your eye health with the help of a professional, our retina specialists can help. Please call our practice today and request an appointment for a consultation.