What is Diabetic Eye Disease?
Diabetic eye disease can affect many parts of the eye, including the retina, macula, lens and optic nerve. A diabetic eye disease is a group of eye conditions that can affect people with diabetes.
Diabetic retinopathy affects blood vessels in the light-sensitive tissue called the retina that lines the back of the eye. It is the most common cause of vision loss among people with diabetes and the leading cause of vision impairment and blindness among working-age adults.
Diabetic macular edema (DME). A consequence of diabetic retinopathy, DME is swelling in an area of the retina called the macula. Diabetic eye disease also includes cataracts and glaucoma.
What Causes Diabetic Retinopathy?
Chronically high blood sugar from diabetes is associated with damage to the tiny blood vessels in the retina, leading to diabetic retinopathy. The retina detects light and converts it to signals sent through the optic nerve to the brain. Diabetic retinopathy can cause blood vessels in the retina to leak fluid or hemorrhage (bleed), distorting vision. In its most advanced stage, new abnormal blood vessels proliferate (increase in number) on the surface of the retina, which can lead to scarring and cell loss in the retina.
What is Diabetic Macular Edema?
DME is the build-up of fluid (edema) in a region of the retina called the macula. The macula is important for the sharp, straight-ahead vision that is used for reading, recognizing faces, and driving. DME is the most common cause of vision loss among people with diabetic retinopathy. About half of all people with diabetic retinopathy will develop DME. Although it is more likely to occur as diabetic retinopathy worsens, DME can happen at any stage of the disease.
Who is At Risk for Diabetic Retinopathy?
People with all types of diabetes (type 1, type 2 and gestational) are at risk for diabetic retinopathy. Risk increases the longer a person has diabetes. Between 40 and 45 percent of Americans diagnosed with diabetes have some stage of diabetic retinopathy, although only about half are aware of it. Women who develop or have diabetes during pregnancy may have rapid onset or worsening of diabetic retinopathy.
What are the Symptoms?
The early stages of diabetic retinopathy usually have no symptoms. The disease often progresses unnoticed until it affects vision. Bleeding from abnormal retinal blood vessels can cause the appearance of “floating” spots. These spots are sometimes clear on their own. But without prompt treatment, bleeding often recurs, increasing the risk of permanent vision loss. If DME occurs, it can cause blurred vision.
How are Diabetic Retinopathy and DME Detected?
Diabetic retinopathy and DME are detected during a comprehensive dilated eye exam that includes:
Visual Acuity Testing. This eye chart test measures a person’s ability to see at various distances.
Tonometry. This test measures pressure inside the eye.
Pupil Dilation. Drops placed on the eye’s surface dilate (widen) the pupil, allowing a physician to examine the retina and optic nerve.
Optical Coherence Tomography (OCT). This technique is similar to ultrasound but uses light waves instead of sound waves to capture images of tissues inside the body. OCT provides detailed images of tissues that can be penetrated by light, such as the eye.
If DME or severe diabetic retinopathy is suspected, a fluorescein angiogram may be used to look for damaged or leaky blood vessels. In this test, a fluorescent dye is injected into the bloodstream, often into an arm vein. Pictures of the retinal blood vessels are taken as the dye reaches the eye.
How Can People With Diabetes Protect Their Vision?
Vision lost to diabetic retinopathy is sometimes irreversible. However, early detection and treatment can reduce the risk of blindness by 95 percent. Because diabetic retinopathy often lacks early symptoms, people with diabetes should get a comprehensive dilated eye exam at least once a year. People with diabetic retinopathy may need eye exams more frequently. Women with diabetes who become pregnant should have a comprehensive dilated eye exam as soon as possible. Additional exams during pregnancy may be needed.
Treatment for diabetic retinopathy is often delayed until it starts to progress to PDR, or when DME occurs. Comprehensive dilated eye exams are needed more frequently as diabetic retinopathy becomes more severe. People with severe non-proliferative diabetic retinopathy have a high risk of developing PDR and may need a comprehensive dilated eye exam as often as every 2 to 4 months.
How is DME Treated?
DME can be treated with several therapies that may be used alone or in combination.
Anti-VEGF Injection Therapy. Anti-VEGF drugs are injected into the vitreous gel to block a protein called vascular endothelial growth factor (VEGF), which can stimulate abnormal blood vessels to grow and leak fluid.
Focal/Grid Macular Laser Surgery. In focal/grid macular laser surgery, a few to hundreds of small laser burns are made to leaking blood vessels in areas of edema near the center of the macula. Laser burns for DME slow the leakage of fluid, reducing swelling in the retina.
Corticosteroids. Corticosteroids, either injected or implanted into the eye, may be used alone or in combination with other drugs or laser surgery to treat DME.
WHAT IS A VITRECTOMY?
A vitrectomy is the surgical removal of the vitreous gel in the center of the eye. The procedure is used to treat severe bleeding into the vitreous and is performed under local or general anesthesia. Ports (temporary water-tight openings) are placed in the eye to allow the surgeon to insert and remove instruments, such as a tiny light or a small vacuum called a vitrector. A clear salt solution is gently pumped into the eye through one of the ports to maintain eye pressure during surgery and to replace the removed vitreous. The same instruments used during vitrectomy also may be used to remove scar tissue or to repair a detached retina.
What if Treatment Doesn’t Improve Vision?
An eye care professional can help locate and make referrals and suggest devices that may help make the most of the remaining vision. Many community organizations and agencies offer information about low vision counseling, training, and other special services for people with visual impairment. A nearby school of medicine or optometry also may provide low vision and rehabilitation services.
If you have diabetes and want to protect your vision, schedule an appointment with VisionQuest Eyecare.
Dr. Collin Rush is passionate about bringing clear eyesight and better eye health to the community. Having graduated in the top 1% of his class at Indiana University School of Optometry, Dr. Rush primarily focuses on dry eye and keratoconus but is also trained in laser therapies for glaucoma and secondary cataracts.