Diabetes affects your body from head to toe. This includes your eyes. The most common and most serious eye complication of diabetes is diabetic retinopathy, which may result in poor vision or even blindness.
“Retinopathy” is the medical term for damage to the tiny blood vessels (capillaries) that nourish the retina, the tissue at the back of your eye that captures light and relays information to your brain. These blood vessels are often affected by the high blood sugar levels associated with diabetes.
Nearly half of people with known diabetes have some degree of diabetic retinopathy. The longer you have diabetes, the more likely it is you’ll develop diabetic retinopathy. Initially, most people with diabetic retinopathy experience only mild vision problems. But the condition can worsen and threaten your vision.
The threat of blindness is scary. But with early detection and treatment, the risk of severe vision loss from diabetic retinopathy is small. You can take steps to protect your sight if you have diabetes. These include a yearly eye examination and steps to keep your blood sugar, blood pressure and blood cholesterol under the best possible control.
Diabetic retinopathy is caused by damage of the blood vessels in the retina. Nonproliferative diabetic retinopathy develops first when the vessels in the eye become larger in certain spots. Proliferative diabetic retinopathy is the advanced form of the disease where new blood vessels start to grow in the eye.
Diabetic Retinopathy is caused due to diabetes problems that inadvertently affect the eye at a certain stage. Diabetes eye problem that requires treatment if some or more of the symptoms occur: blurry or double vision, dark or blank spots, pain or pressure in eyes and trouble seeing from the corner of the eyes.
Having diabetes puts you at risk of retinopathy, whether you have type1diabetes or type2 diabetes. Your risk increases the longer you have the disease.
Other risk factors for diabetic retinopathy include:
- Poorly controlled blood sugar levels
- High blood pressure
- High blood cholesterol
- Hispanic or African-American heritage
Screening and Diagnosis
Your eye doctor is likely to diagnose diabetic retinopathy, either nonproliferative or proliferative, if an eye examination reveals any of the following:
- Leaking blood vessels.
- Retinal hemorrhage.
- Swollen retina.
- Fatty deposits (exudates) in the retina.
- Areas of nerve fiber damage (cotton-wool spots).
- Changes in blood vessels, such as closures, beading or loops.
- Formation of new blood vessels (neovascularization).
- Vitreous hemorrhage.
- Scar tissue formation with retinal detachment.
As part of an eye examination, your doctor may include a diagnostic procedure called fluorescein angiography to identify leaking blood vessels. In fluorescein angiography, your doctor injects a dye into a vein in your arm. The dye circulates through your eyes, making the blood vessels in your retina easy to identify. Your doctor can pinpoint areas where normal blood vessels have become closed or have broken down and are leaking fluid. A camera with special filters takes flash pictures every few seconds for several minutes, providing your doctor with useful images. Your doctor also may request an optical coherence tomography (OCT) examination. This noninvasive imaging scan provides high resolution images of the retina that show, for example, the thickness of the retina and whether fluid has leaked into retinal tissue. OCT exams can be useful both as a diagnostic tool and as a way of monitoring treatment effectiveness.
The goal of photocoagulation, also known as laser treatment, is to stop the leakage of blood and fluid in the retina and thus slow the progression of diabetic retinopathy and vision loss. The decision to use the procedure depends on the type of diabetic retinopathy you have, its severity and how well it may respond to treatment.
Your doctor may recommend photocoagulation if you have:
- Diabetic macular edema, a swelling that involves or threatens the center of the retina.
- Severe nonproliferative diabetic retinopathy, especially if you have type 2 diabetes.
- Proliferative diabetic retinopathy.
- Neovascular glaucoma.
In photocoagulation, a high-energy laser beam creates small burns in areas of the retina with abnormal blood vessels to help seal any leaks. The procedure takes place in your doctor’s office or in an outpatient surgical center. Before surgery your eye doctor dilates your pupil and applies anesthetic drops to numb your eye. In some cases he or she numbs your eye more completely by injecting anesthetic around and behind your eye.
First, your chin and forehead are rested in an examination device called a slit lamp. This is a microscope that uses an intense line of light (slit) to allow your doctor to clearly view portions of your eye. Then, your doctor places a medical contact lens on your cornea, the layer of clear tissue at the front of your eye, to help focus laser light onto the sections of the retina to be treated.
Fluorescein angiographic photographs may serve as maps to show where the laser burns should be placed. During the procedure you may see bright flashes from the short bursts of high-energy light. To treat macular edema, the laser is focused on spots where blood vessels are leaking near the macula. The doctor makes “spot welds” to stop the leakage.
If the leaks are small, the laser is applied directly to specific points where the leaks occur (focal laser treatment). If the leakage is widespread or diffuse, laser burns are applied in a grid pattern over a broad area (grid laser treatment).
Shortly after laser treatment, you can usually return home, but you won’t be able to drive, so make sure to arrange for a ride. Your vision will be blurry for about a day. Even when laser surgery is successful in sealing the leaks, new areas of leakage may appear later. For this reason you’ll have follow-up visits and, if necessary, additional laser treatments.
Immediately following laser surgery to treat macular edema, small spots caused by the laser burns may appear in your visual field. The spots generally fade and disappear with time. If you have blurred vision from macular edema before surgery, you may not recover completely with normal vision.
For proliferative diabetic retinopathy, doctors use a form of laser surgery called panretinal or scatter photocoagulation. With this technique the entire retina except the macula is treated with scattered laser burns. The treatment causes abnormal new blood vessels to shrink and disappear. Thus it reduces the chances of a vitreous hemorrhage and traction retinal detachment. Panretinal photocoagulation is usually done in two or more sessions.
You may notice some loss of peripheral vision afterward. Panretinal photocoagulation is a trade-off. Some of your side vision is sacrificed to save as much of your central vision as possible. You may also notice difficulties with your night vision.
A vitreous hemorrhage may clear up on its own. But if the hemorrhage is massive and doesn’t clear, a vitrectomy may help to restore your sight and may allow the application of needed laser treatment.
In this procedure your surgeon uses delicate instruments to remove the blood-filled vitreous. A vitreous cutter cuts the tissue and removes it, piece by piece, from your eye. The tissue that is removed is replaced with a balanced salt solution to maintain the normal shape and pressure of the eye. A light probe illuminates the inside of the eye. The surgeon performs the procedure while looking through a microscope suspended over the eye. In this way the vitreous blood is removed to re-establish clear vision. A vitrectomy is also used to remove scar tissue when it begins to pull the retina away from the wall of the eye.
This allows a detached retina to settle back and flatten out. Your eye doctor may decide not to operate on a retina detached by scar tissue if the detachment is located away from the macula and doesn’t appear to be progressing. During a vitrectomy the surgeon may also use a laser probe to perform panretinal photocoagulation. This can help prevent renewed growth of abnormal blood vessels, bleeding and scar tissue formation.
Vitrectomy can be performed under local or general anesthesia. Sometimes it is necessary to inject a bubble of expandable gas into the eye cavity. As the gas bubble expands, it pushes on the retina and helps it reattach. You may be required to remain in a face-down position for several days until the gas bubble spontaneously goes away. Your eye will be red, swollen and sensitive to light for some time after surgery. For a short time afterward, you’ll need to wear an eye patch and apply medicated eye drops to help the healing. Full recovery may take weeks.
You can take steps to slow the progression of diabetic retinopathy.
Control your blood sugar
Tight control of blood sugar slows the onset and progression of retinopathy and lessens the need for surgery. Tight control means keeping your blood sugar levels as close to normal as possible. Ideally, this means levels between 90 and 130 milligrams per deciliter (mg/dL) before meals and less than 180 mg/dL two hours after starting a meal – with a glycosylated hemoglobin A1C level less than 6 percent. A glycosylated hemoglobin A1C test, also called a glycated hemoglobin test, reflects your average blood sugar level for the two- to three-month period before the test. Your doctor uses it to determine how well you’re managing your blood sugar.
Tight control isn’t possible for everyone, including some older adults, young children and people with cardiovascular disease. Talk to your doctor, your endocrinologist or diabetes educator about the best blood sugar control goals and management plan for you. A management plan frequently involves taking insulin or other medications, monitoring blood sugar levels, following a healthy eating plan, getting regular exercise and maintaining a healthy weight. It may take some time before the benefits of lowering your blood sugar are realized. And remember that better control lowers but doesn’t eliminate your risk of developing retinopathy.
Keep an eye on vision changes
In addition to getting an annual eye exam, be alert to any sudden changes in your vision. Have your eyes checked promptly if you experience vision changes that last more than a few days or aren’t associated
with a change in blood sugar, or if your vision becomes blurry, spotty or hazy.
Keep your blood pressure down
Tight blood pressure control slows the progression of diabetic retinopathy.
To reduce your blood pressure, you may need to make lifestyle changes and take medications.
Control your cholesterol
Total blood cholesterol levels above 240 mg/dL are associated with a significantly increased risk of vision loss. As with high blood pressure, treatments to improve your blood cholesterol may include lifestyle changes and medications.
Smoking is especially bad for people with diabetes because it promotes the closure of blood vessels.
Stress can cause swings in blood sugar levels in people with diabetes. Stress may affect your ability to control your blood sugar. For example, you may be too busy to exercise or eat a good meal. Stress hormones also can directly affect your blood sugar levels, causing them to rise or fall. Don’t hesitate to seek help from a counselor, therapist or support group to control your stress. Relaxation techniques such as meditation also may be helpful.