What is diabetic retinopathy?
Diabetic retinopathy is the most common eye disease affecting people with diabetes. This complication of diabetes is the result of chronically elevated blood sugar levels damaging small blood vessels in the retina. The retina is the light-sensing tissue at the back of the eye. When light hits it, it sends signals to the optic nerve, which carries the information to the brain.
Chronically high blood sugar levels can cause tiny blood vessels to leak fluid and blood into the retina tissue. This results in swelling of the retina. The damage can also cause the vessels to close off completely, which prevents nourishing blood from flowing to the retina. The body reacts by trying to grow new blood vessels to feed the retina. However, these new abnormal blood vessels are defective and can begin leaking, making the problem worse.
As it progresses, diabetic retinopathy causes vision problems and eventually blindness. In fact, it’s a leading cause of blindness in American adults. Fortunately, doctors can find it in the early stages with a complete dilated eye exam. In some cases, eye doctors can help diagnose diabetes based on an eye exam in adults who don’t even know they have it.
About 2 in 5 people with diabetes have some degree of retinopathy. The longer you have diabetes, the higher your risk of developing it. The risk is especially high when your blood sugar levels are poorly controlled. Once you have diabetic retinopathy, your risk of progression depends on the severity of the disease and your blood sugar control.
Intensive blood sugar control can reduce the risk of progression by 54%. Controlling high blood pressure, if you have it, can also slow progression of diabetic retinopathy. If treatment becomes necessary, options include eye injections, laser treatments, and surgery. Left untreated, diabetic retinopathy will ultimately lead to blindness. See your eye doctor promptly if you notice vision changes. Contact your doctor right away if you have sudden vision changes.
What are the symptoms of diabetic retinopathy?
In the early stages of diabetic retinopathy, symptoms are often absent or very mild if they are present. This can make it hard to notice that you are having problems. As the disease progresses, symptoms can become more evident. Symptoms typically affect both eyes.
Common symptoms of diabetic retinopathy
Common diabetic retinopathy symptoms include:
- Blurry vision or vision that fluctuates between blurry and clear
- Dark or blank spots in your vision
- Floaters, which increase in number
- Poor night vision
- Trouble with colors appearing faded
Serious symptoms that might indicate a serious condition
In some cases, advanced diabetic retinopathy can lead to retinal detachment. This is a medical emergency because it can lead to permanent vision loss. Seek immediate medical care (call 911) if you, or someone you are with, have any of these serious symptoms including:
- Curtain-like shadow over your vision
- Flashes of light in one or both eyes
- Reduced side—or peripheral—vision
- Sudden blurry, hazy or spotty vision or sudden appearance of floaters
If you have diabetes, regular eye care is a vital part of your overall treatment plan. See your eye doctor at least once a year for a comprehensive dilated eye exam. Finding potential problems with your retina early can mean the difference between keeping your vision or having diabetic retinopathy steal it.
What are the stages of diabetic retinopathy?
There are four stages of diabetic retinopathy, depending on whether new, abnormal blood vessels are growing. Because the medical term for this new growth is proliferation, the stages of diabetic retinopathy are divided into non-proliferative (NPDR) and proliferative (PDR).
- Mild NPDR: Aneurysms develop in the retina’s blood vessels. These tiny balloon-like spots can leak fluid, including blood, into the retina. There are no symptoms at this stage.
- Moderate NPDR: Larger areas of blood vessels swell and the damage causes leakage of fluid, including blood and fats. Damaged blood vessels reduce normal blood flow to the retina, which in turn damages the retina itself. Blurry vision is possible with non-proliferative diabetic retinopathy.
- Severe NPDR: Restricted blood flow to the retina and other factors signal the body to grow new blood vessels for the retina. This is the beginning of the proliferative stage.
- PDR: The new blood vessels are numerous and thin-walled, which makes them more likely to bleed and leak into the vitreous—the gel-like substance within the eye. Scar tissue develops over the retina, which can cause retinal detachment and permanent vision loss. Before complete vision loss, people with PDR may notice ‘floaters’ in their vision. Eye floaters are dark spots created from bleeding blood vessels.
Clinicians also use the term vision-threatening diabetic retinopathy (VTDR) which includes:
- Severe nonproliferative diabetic retinopathy
- Proliferative diabetic retinopathy
- Diabetic macular edema. The risk of macular edema increases with worsening retinopathy, but it can occur at any stage.
In the United States alone, about 5.5 million adults have diabetic retinopathy and 1.2 million have VTDR. Following the increase in diabetes across the country, these numbers are predicted to triple by 2050. Prevalence will more than triple for diabetics 65 and older.
What causes diabetic retinopathy?
The cause of diabetic retinopathy is chronically elevated blood sugar levels. High blood sugar damages tiny blood vessels in the retina. The longer blood sugar levels remain uncontrolled, the more damage occurs. Diabetic retinopathy progresses in stages from non-proliferative to proliferative.
From severe non-proliferative to proliferative diabetic retinopathy, cumulative vascular damage causes new blood vessels to grow—or proliferate. These new, but abnormal vessels bleed easily into the clear gel that fills the eye—the vitreous humor. Scar tissue forms as the vessels heal. The scar tissue can create traction on the retina and block the normal flow of fluid through the eye.
What are the risk factors for diabetic retinopathy?
Having diabetes means you are at risk of developing diabetic retinopathy. The likelihood of developing it increases with the duration of diabetes. Having poorly controlled blood sugar also increases the likelihood. Other factors that make diabetic retinopathy more likely include:
- Being African American, Native American, or Hispanic
- Being pregnant
- Having high blood pressure or high cholesterol, both of which damage blood vessels
- Smoking or using tobacco
Reducing your risk of diabetic retinopathy
You can’t always prevent diabetic retinopathy. In fact, some people first find out they have diabetes when an eye doctor discovers problems in the retina. It’s very common for people with diabetes to have some degree of retinopathy. Fortunately, there are steps you can take to reduce the risk of progression of the disease including:
- Controlling your blood sugar. Intensive blood sugar control can reduce the risk of progression by 54% in people with mild to moderate retinopathy at baseline. When there is no retinopathy at baseline, it can reduce the risk of developing it by 76%.
- Controlling your blood pressure. For people with high blood pressure and diabetes, tight blood pressure control can reduce the risk of retinopathy progression by 34%.
Two other important strategies to protect your vision include stopping smoking and treating high cholesterol if you have it. Of course, seeing your eye doctor on a regular basis should also be part of your plan to protect your vision. People with diabetes need a comprehensive dilated eye exam at least once a year.
What are some conditions related to diabetic retinopathy?
Conditions related to diabetic retinopathy include:
- Diabetic macular edema—swelling of the macula part of the retina caused by retinopathy. DME is the most common cause of vision loss in diabetics.
- Cataract—clouding of the lens of the eye that occurs more frequently in people with diabetes.
- Glaucoma—increased pressure that damages the optic nerve; occurs with greater frequency in diabetics compared to the general population.
How do doctors diagnose diabetic retinopathy?
Diabetic retinopathy and diabetic macular edema can be diagnosed during a comprehensive dilated eye exam. With the eye dilated, the eye doctor can examine the retina and check for:
- Abnormal blood vessels
- New blood vessels or scar tissue
- Signs of leaking blood vessels
- Macular edema
- Changes in the lens such as cataract
- Nerve damage
Some eye clinics have equipment to photograph the retina at high resolution. This is important for the eye doctor to track the health of the retina over time, which helps diagnose diabetic retinopathy in its earliest stages. People with diabetes should have a dilated eye exam every year, and those with diabetic retinopathy need more frequent exams. Pregnant women with diabetes should see an ophthalmologist in the first trimester.
If the doctor suspects retinopathy or macular edema, an angiogram of the eye and other imaging studies can be performed to highlight the abnormal changes and help guide treatment if necessary.
How is diabetic retinopathy treated?
For mild to moderate diabetic retinopathy, immediate treatment may not be necessary. Instead, your eye doctor may recommend closely monitoring your vision with eye exams. Good blood sugar control can help prevent progression at this stage. So, your diabetes doctor will need to evaluate your diabetes management. Together, you can find ways to improve your treatment with diet, exercise and medication.
When diabetic retinopathy becomes advanced or proliferative, treatment is usually necessary. Your ophthalmologist may recommend the following treatment options:
- Eye injections into the vitreous with vascular endothelial growth factor (VEGF) inhibitors to stop the formation of new blood vessels in the retina.
- Focal laser photocoagulation to slow or stop the leakage of fluid and blood into the eye by burning leaky areas to seal them
- Panretinal photocoagulation or scatter laser treatment to decrease proliferation of abnormal blood vessels
- Vitrectomy to surgically remove blood from the vitreous cavity and scar tissue pulling on the retina
Unfortunately, diabetic retinopathy treatment is not a cure. The underlying problem, diabetes, is still present. So, there will always be a risk of future problems and vision loss. You will still need regular eye care and medical care to manage your diabetes and protect your vision.
What are the potential complications of diabetic retinopathy?
Your diabetic retinopathy prognosis depends on several factors. This includes the severity of the retinal damage and your blood sugar control. Potential complications of diabetic retinopathy include:
- Glaucoma, which can happen when new blood vessels and scar tissue develops in the front part of the eye. This interferes with the normal outflow of fluid and increases pressure inside the eye. This pressure can eventually damage the optic nerve, causing vision problems and vision loss.
- Retinal detachment, which is a medical emergency. It happens when scar tissue pulls the retina off the wall of the eye. Without immediate treatment, retinal detachment can lead to permanent vision loss.
- Vitreous hemorrhage, which occurs when leaky blood vessels bleed into the gel that fills the eye. Severe hemorrhages can completely block your vision. Most cases clear up within weeks or months. However, if the retina is damaged in the process, vision loss can be permanent.
Ultimately, diabetic retinopathy will lead to blindness without proper treatment. To protect your vision, follow your diabetes management plan closely and see your eye doctor on a regular basis.
How does diabetic retinopathy affect quality of life?
One way to understand the impact of vision loss from diabetic retinopathy is to study its effect on patient quality of life, which includes physical, mental and social well-being. The more diabetic retinopathy affects vision, the more severe its impact on health-related quality of life, based on quality of life questionnaires that include vision-specific questions.
The effects of diabetic retinopathy are most pronounced in social and emotional health. Beyond its disability, vision loss from diabetic retinopathy has a negative effect on family, social activity and relationships, and work, which in turn impacts finances.
This information supports efforts in early diagnosis and prevention of diabetic retinopathy, but also means it is important to offer treatment and support to patients who develop diabetic retinopathy and vision loss.
Diabetic retinopathy awareness
Education, awareness and screening for diabetes and diabetic retinopathy can improve prevention and decrease its burden. The Centers for Disease Control (CDC) launched the Vision Health Initiative in 2007 to identify populations at risk for eye disease (including diabetic retinopathy), increase awareness of eye health, and improve access to eye care at the state and local level.
November is Diabetic Eye Disease Awareness Month.