Diabetic Retinopathy

What is diabetic retinopathy?

What is diabetic retinopathy?

Diabetes increases the risk of glaucoma, cataracts, and other eye problems. Diabetic retinopathy is a complication of diabetes that causes damage to the blood vessels of the retina, the thin and delicate tissue that lines the back of the eye and allows you to see fine detail. It is the most common type of diabetic eye disease, and the leading cause of irreversible blindness in working-age Americans.

What are the causes of diabetic retinopathy? How does it cause vision loss?

Elevated blood sugar levels resulting from diabetes can damage the small blood vessels that nourish the retina. These damaged blood vessels can leak fluid within the retina and cause swelling in the macula, the portion of the retina that provides the sharp vision needed for reading, driving and recognizing faces. This is known as diabetic macular edema, and it is the most common cause of decreased vision in diabetic retinopathy. As the condition worsens, there is less blood flow to the macula, which causes macular ischemia.

The decreased blood flow can be irreversible, and in some cases result in limited vision.

As the damage progresses, poor circulation to the retina and macula promotes the release of growth factors that cause new, abnormal blood vessels to develop. These blood vessels grow on the surface of the retina and can lead to bleeding, scarring and retinal detachments in a stage known as proliferative diabetic retinopathy. During this phase of the disease, a vitreous hemorrhage can develop, resulting in multiple floaters, which can be dense enough to cause severe vision loss.

What are the risk factors of diabetic retinopathy?

Proliferative diabetic retinopathy

Anyone with diabetes (types 1 or 2) is at risk of developing di abetic retinopathy. The important risk factors include:

Duration of Diabetes: Epidemiologic studies have shown that the longer you have diabetes, the higher your risk of developin g diabetic retinopathy. In type 1 diabetic patients, nine out of ten patients will suffer from the disease within 10-15 years of developing diabetes. With type 2 diabetic patients, one out of three has diabetic retinopathy at the time of their diabetes diagnosis, and eight out of ten have diabetic retinopathy 15 years after developing diabetes.

Sugar Control Over Time: Multiple studies have demonstrated that better sugar control results in decreased risk of diabetic retinopathy complications―and in slowing the progression of diabetic retinopathy. For every 1% decrease in HbA1C, there is a 40% reduction in the incidence of diabetic retinopathy. In general, diabetic patients who kept their blood sugar levels as close to normal as possible also were found to have significantl y less kidney and nerve disease. Better control also reduced the need for therapies to treat diabetic retinopathy. Patients should routinely see their primary care provider, who can determine the best form of blood sugar control for them.

Blood Pressure Control: Here, too, studies have shown that better control of blood pressure results in both decreasing the risk of contracting diabetic retinopathy and slowing the progression of the disease. Better blood pressure control resulted in less need for laser therapy to treat diabetic retinopathy. And it is proven that, additionally, controlling your blood pressure promotes overall better health.

Cholesterol level elevation is also associated with the worsening of diabetic retinopathy. Pregnancy can also worsen diabetic retinopathy, so during this period it might be necessary to be monitored more closely by your retina specialist.

In general, maintaining better overall control of your health in coordination with your primary medical doctor will lead to improved management of your diabetic retinopathy and decrease the need to have sight-saving treatments and interventions.

Diabetic macular adema

Early detection and treatment can prevent vision loss. If you are diabetic, be sure to schedule a comprehensive dilated eye exam at least once a year. It is important to remember that your diabetic retinopathy can progress without symptoms. You can develop both proliferative retinopathy or macular edema and still see normally, but you may remain at high risk for vision loss. Your retina specialist can determine if you have entered any stage of diabetic retinopathy or macular edema. Depending on the severity of either disease, he or she may suggest more frequent exams in order to more closely monitor your condition.

What are the symptoms of diabetic retinopathy?

There are often no symptoms during the early stages of the dise ase, nor is there any discernable pain. It is important, therefore, not to wait until you experience symptoms, and to have a comprehensive dilated eye exam at least once a year.

When symptoms do occur, they range from mildly blurred central vision to complete vision loss―and they can progress slowly or rapidly. It is critical to secure prompt medical attention if you noti ce any change in your vision.

Proliferative diabetic retinopathy frequently produces symptoms as a result of bleeding into the vitreous cavity. At first, you may notice a few specks of blood “floating” in your vision. If that occurs, see your retina specialist immediately. You may need treatment before more serious bleeding occurs. Hemorrhages tend to occur more than once, often during sleep.

On some occasions, the spots clear without treatment and your vision improves. It is likely, however, that the bleeding will reoccur and cause severe vision loss. You need to be examined by your retina specialist at the first sign of blurred vision. The close r you maintain contact with your retina specialist and the earlier you receive medical attention, the more likely that the treatment will be effective. If left untreated, proliferative retinopathy can lead to severe vision loss and even permanent blindness.

How is diabetic retinopathy diagnosed?

Diabetic retinopathy is detected during a comprehensive eye exam. After a check of your vision and eye pressure, drops are placed in your eyes to dilate, or widen, the pupils. Your retina specialist uses a special magnifying lens to examine your retina for signs of dia betic retinopathy, looking for:

  • Swelling and thickening of the retina that threatens central vision
  • Poor retinal blood vessel circulation
  • Growth of new abnormal blood vessels on the surface of the retina
  • Scar tissue formation on the retina that can lead to retinal detachment

It may be appropriate to conduct some special tests to help determine the stage of the retinopathy and/or decide if treatment is needed.


Here are a few of the specific tests that might be performed:

Fundus Photograph: Using a specialized camera that focuses on the retina, photographs of the back of the eye are taken to both detect and document the diabetic retinopathy. These allow for easier comparison and monitoring of the progression of diabetic retinopathy on follow-up visits.

Optical Coherence Tomography (OCT): This is a non-invasive test— similar to an ultrasound—that uses simple light to obtain highly detailed images of the macula, the functional center of the retina responsible for our high resolution and color vision. The OCT will be conducted at each visit to help determine if there is any diabetic macular edema present.

Fluorescein Angiogram: This test requires the injection of a special organic vegetable dye into the vein(s) in your arm. Photos are taken as the dye passes through the blood vessels in your retina, and identifies any leaking blood vessels that may require treatment. Unlike the dye used with MRIs and CT scans, this dye does not affect the kidneys. Since the dye is different, those patients with allergies to dyes used in MRIs and CT scans may undergo a fluorescein angiogram without concern.

After the exam, your close-up vision may remain blurred for several hours due to the dilating drops. Proper examination, testing and timely follow up allow for early detection of diabetic retinopathy and its complications before they result in vision loss. Your retina specialist will determine those tests needed to help assess your condition, and the nature and frequency of follow-up treatment most appropriate for your circumstances.

What are the four stages of diabetic retinopathy?

Mild Non-proliferative Diabetic Retinopathy

The features of mild non-proliferative retinopathy manifest some of the earliest stages of diabetic retinopathy. Small areas of balloonlike dilation of blood vessels, called microaneurysms, start to appear, along with small intraretinal hemorrhages and cotton wool spots. It’s important to note that not all patients with mild n onproliferative retinopathy will experience a change in their vision.

Moderate Non-proliferative Diabetic Retinopathy

Moderate non-proliferative retinopathy is a progression from th e mild stage. Many more microaneurysms, intraretinal hemorrhages and cotton wool spots emerge and there is further damage to the retinal blood vessels. The danger is that such damage can resul t in reduced blood flow to the surrounding retinal tissue, leadin g to vision loss.

Severe Non-proliferative Diabetic Retinopathy

As the retinopathy progresses and more blood vessels have been affected, a larger area of the retina has been deprived of blood flow. This results in the retina producing new blood vessels in an at tempt to enhance nourishment, which can result in vision loss.

Proliferative Diabetic Retinopathy

At this advanced stage, the signals sent by the retina for nourishment trigger the growth of new blood vessels along the retina and into other parts of the eye. These blood vessels, while abnormal and fragile, do not produce new or worsen existing symptoms or vision loss. Over time, however, they have a tendency to bleed and pull on the retina. Left untreated, severe vision loss and even permanent blindness can occur.

How is non-proliferative diabetic retinopathy treated?

During the stages of mild and moderate non-proliferative diabetic retinopathy, no treatment is needed unless macula edema is present. To prevent the progression of diabetic retinopathy, people with diabetes should control their blood sugar, blood pressure and cholesterol in coordination with seeing their primary care doctor.

If you develop macular edema, your vision might be affected and reduced. Fortunately, results of many major clinical trials have led to the development of numerous approved treatments for diabetic retinopathy. These include intravitreal injections of medications into the central cavity of the eye, and focal laser therapy.

Intravitreal medications have a temporary effect and, unfortunately, you might need repeated injections to better control your diabetic retinopathy. Depending on the specifics of the disease, your retina specialist will recommend one of the following:

Syringe with needle

Anti-Vascular Endothelial Growth Factor (VEGF): Research has shown that VEGF plays a major role in stimulating leakage within the macula and development of abnormal blood vessels.

These medications block the VEGF signal to decrease the diabetic macular edema. There are three different anti-VEGF medications that can be injected into the eye: bevacizumab (Avastin®), ranibizumab (Lucentis®) and aflibercept (Eylea®). All three produce similar benefits in treating diabetic retinopathy, and recently the FDA approved the use of Lucentis for any stage of diabetic retinopathy.

Steroids: These medications work both on stopping the VEGF signal and on other signals that lead to leakage within the macula. Your retina specialist may recommend these medications as an option. There are three different steroids: triamcinolone, Ozurdex® and Iluvein®. Depending on the degree of your diabetic retinopathy, your retina specialist might recommend steroids as part of your treatment plan.

Focal laser treatment

Focal laser treatment is conducted with a special laser that seals the leaking blood vessels, thus slowing the leakage of fluid and reducing the amount of fluid within the macula. Your retina specialist might recommend more than one session to better control the leaking fluid. Given the development of so many intravitreal medications, focal laser is not used as frequently, but still plays a major role in controlling diabetic retinopathy.

How is proliferative diabetic retinopathy treated?

In addition to the intravitreal medications mentioned above, there are two major therapies for the treatment of proliferativ e diabetic retinopathy—panretinal photocoagulation laser treatment and vitrectomy.

Scatter Laser Treatment (Panretinal Photocoagulation)

Panretinal photocoagulation laser treatment is an in-office procedure that helps to shrink the abnormal blood vessels that cause bleeding and scarring. Your retina specialist places laser spots throughout the entire peripheral retina, causing the abnormal blood vessels to shrink. Because it’s necessary to use a large number of laser spots, more than one session is often required to complete the treatment. Although you may notice some loss of side vision―and it may slightly reduce your color and night vision―this laser treatment is needed to preserve your central vision. It is more effective before the fragile, new blood vessels have started to bleed, which is why it is so important to have regular, comprehensive dilated eye exams. Even if bleeding has begun, scatter laser treatment may still be possible, depending on the amount of bleeding.

In some instances, intravitreal medications may be used in conjunction with laser to treat severe forms of proliferative diabetic retinopathy.

Some degree of discomfort is common with panretinal photocoagulation laser treatment. It typically subsides at the end of the procedure, but some patients report mild discomfort or a slight headache that can last for the rest of the day.


Syringe with needle

You may require a surgical procedure called a vitrectomy if the bleeding is severe, if it does not clear up on its own, or if you develop a retinal detachment related to your diabetic retinopathy. This procedure is almost always performed on an out-patient basis under local anesthesia. Your doctor inserts tiny instruments through small incisions in the sclera―the white portion of the eye―and removes the gel and blood from the center of the eyeball. He or she wil l then replace the clouded gel with a clear saline solution, gas bubbl e or silicone oil. The gas bubble will gradually dissipate on its ow n; a second procedure is needed to remove the silicone oil. Following the procedure, an eye patch is placed on the operated eye and you need to return to the office the next day.

Prior to the procedure, your doctor will explain the rare but p ossible complications of vitrectomy surgery.

What happens during an intravitreal injection?

Intravitreal injections are performed in your doctor’s office. Before the treatment, your retina specialist dilates, examines and assesses both of your eyes. Numbing drops will be applied to your eye, followed by a sterilizing solution to prevent infections. After a few minutes, your eye will be numb and your retina specialist will use a small tool called a speculum to help keep the eyelids open.

The medications are then injected into the middle cavity of the eye using a small needle. You will feel pressure as the medication is injected into the eye, and generally there is little to no discomfort associated with the procedure. Following your treatment, you will not experience any decline in vision. In some patients, the pressure of the eye may transiently rise, which your retina specialist can treat if needed. After the injection, your eye might feel dry on the first day and you may use overthecounter artificial tears to help alleviate those symptoms. You should call your retina specialist if any abnormal symptoms develop.

What happens during laser treatment?

Focal laser treatments are performed in the office with the lights dimmed. Before the treatment, your physician will dilate your pupil and apply drops to numb the eye. As you sit facing the laser machine, he or she will hold a special lens to your eye. During the procedure, you will see flashes of bright light. Although the flashing lights are often described as annoying, there is generally little to no discomfort associated with this procedure.

Laser treatment will at best stabilize vision, but in most cases it cannot restore vision that has been lost. This is yet another reason that treating diabetic retinopathy early is the best way to prevent vision loss.

It is highly uncommon to experience a decline in vision following treatment, and with the majority of patients who do, it is a temporary condition. You should call your retina specialist immediately if any abnormal symptoms develop.

What can I do if I already have lost some vision from diabetic retinopathy?

Ask your retina specialist about referring you to a low vision specialist, and how low vision services and devices can help you make the most of your remaining vision. Closed circuit television with electronic magnification and image intensification is a commonly-used aide, as are lens magnifiers combined with a brighter light. Patients are often given the opportunity to test low vision products at home before purchasing them.

What is the best way to prevent diabetic retinopathy?

The National Eye Institute suggests that you keep your health on TRACK:

  • Take your medicines as prescribed by your primary care doctor
  • Reach and maintain a healthy weight
  • Add physical activity to your day
  • Control your ABCs
  • A1C
  • Blood pressure
  • Cholesterol
  • Kick the smoking habit

Regular dilated eye exams, as recommended by your retina specialist, help in reducing the risk of developing severe complications from diabetic retinopathy. It is extremely important for diabetic patients to maintain the eye examination schedule put in place by their retina specialist. Y our examination schedule is determined by the severity of your disease. With early detec tion and regular follow-up, your retina specialist can employ a treatment regimen to prevent vision loss and preserve the activities you most enjoy.

Are there promising therapies in development?

Many major research centers, including The Retina Group of Washington, are conducting and supporting research designed to seek better ways to detect, treat and prevent vision loss in pe ople with diabetes. Researchers are continuing to study drugs that stop the growth of abnormal blood vessels. Someday, these drugs may help people control their diabetic retinopathy and reduce the need for laser surgery.

Ask your doctor if you qualify for one of these studies, or any other questions that you may have.


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