Diabetic Retinopathy: Symptoms and Stages
Diabetic retinopathy symptoms range from none (early in the disease) to vision changes, including trouble reading and difficulty seeing far away. As the disease progresses, other symptoms like blurred vision, dark floating spots, and streaks that look like cobwebs can occur.
These symptoms typically affect both eyes and can come and go. The most severe symptom—vision loss and blindness—is the most frequent cause of new cases of blindness among adults ages 20–74.
When diabetic retinopathy causes other eye conditions, such as glaucoma, you may start to lose your peripheral vision. It is estimated that two in five people with diabetes have some form of diabetic retinopathy.
The good news is that you can prevent, manage, and treat diabetic retinopathy with early detection and adequate blood sugar control.
Frequent Symptoms and Stages of Retinopathy
There are four stages of diabetic retinopathy: mild nonproliferative diabetic retinopathy (NPDR), moderate NPDR, severe NPDR, and proliferative diabetic retinopathy (PDR).
The progression of retinopathy appears to depend on several factors, including retinopathy stage at baseline diagnosis, duration of diabetes, diabetes control, and blood pressure. Other factors commonly associated with the disease include nephropathy (kidney disease) and dyslipidemia.
Many clinical trials have demonstrated a clear relationship between high blood sugar and retinopathy. In fact, studies have found that a 10% reduction in hemoglobin A1C (three-month average of blood sugar) can reduce the risk of retinopathy by 43%.
Mild Nonproliferative Diabetic Retinopathy
This is the first stage of diabetic retinopathy. In this stage, a person may experience no symptoms at all. During this time, small areas of balloon-like swelling (microaneurysms) develop on the tiny vessels in the retina. The microaneurysms may leak fluid into the retina. In addition, hard exudates (fat deposits) are often noted.
While you may not have any symptoms, eye disease can begin before symptoms do. The American Diabetes Association recommends:
- All people newly diagnosed with type 2 diabetes should receive an eye exam shortly after diagnosis and every year thereafter.
- People with type 1 diabetes should receive a dilated eye exam within five years of diagnosis and every year after that.
Moderate Nonproliferative Diabetic Retinopathy
As the disease progresses, more vessels that nourish and support the retina can become weak and blocked. They may also begin to swell and become distorted in size.
The vessels can lose their ability to transport blood, which can result in swelling of the macula and contribute to diabetic macular edema. This can distort clear vision.
As the condition progresses into the later stages, you may experience:
- Fluctuating vision—focus that goes in and out
- Impaired color vision
- Blurry vision
- Dark floating spots
- Difficulty seeing at night
- Streaks that look like cobwebs
Severe Nonproliferative Diabetic Retinopathy
In this stage, even more blood vessels become blocked, which further disrupts blood supply to areas in the retina, such as the macula. The body compensates for this disruption by secreting growth factors that signal the retina to grow new blood vessels.
Proliferative Diabetic Retinopathy
This is the most advanced stage of retinopathy. PDR occurs when the growth factors trigger the proliferation of new blood vessels. They grow along the inside surface of the retina and into the vitreous gel, the fluid that fills the eye. These vessels are weak and do not work efficiently, making them more likely to leak and bleed.
If scar tissue develops, the retina can become detached from the eye, which can lead to permanent vision loss. Damage to retinal neurons and chronic inflammation can also contribute to vision loss.
Advancements in screening, early detection, tight glycemic control, and specialized treatments have helped to reduce the severity of diabetic retinopathy. Prevention and delay of onset and progression of diabetic retinopathy have been demonstrated with intensive diabetes management.
But rare and severe symptoms are still possible, especially for those people with proliferative diabetic retinopathy and diabetic macular edema.
The growth of new blood vessels can cause scar tissue to develop in the retina. When the scar tissue shrinks, it can distort the retina and pull it out of place.
If a small portion of your retina is detached, you may not have symptoms. However, if a larger portion is detached, you may experience an increase in floaters, flashes of light, or a dark shadow or “curtain” in the middle or sides of your eyes.
This is considered a medical emergency and should be treated right away to prevent further damage. Therefore, if you have any symptoms of retinal detachment, you should seek medical attention immediately.
Vision Loss and Blindness
This is the most serious symptom of diabetic retinopathy. Vision loss and blindness typically occur when less severe forms of retinopathy are not treated and a person has had uncontrolled blood sugars for a very long time. Early detection and treatment can limit the potential for serious vision loss.
In people with type 1 diabetes, pregnancy and puberty may accelerate retinopathy. In people with type 1 diabetes who are pregnant, retinopathy can be aggravated especially when blood sugars are elevated at the time of conception.
Researchers cannot say for certain if puberty affects the development of diabetic retinopathy. While some studies have found that the prevalence of retinopathy is lower in people who developed diabetes before puberty, after 20 years that difference disappears.
One way puberty may accelerate the risk of retinopathy is that hormones can impact blood sugars, making them harder to control. Poor glycemic control, which often occurs during puberty, has been associated with an increased risk of diabetic retinopathy.
Additionally, if you smoke and have diabetes, you are at increased risk of developing diabetic retinopathy.
Cataracts occur when your eye’s natural lens becomes cloudy. Cataracts are one of the most common eye complications of diabetes. Having diabetes makes you two to five times more likely to develop cataracts.
Older research suggests that cataract surgery may accelerate the progression of diabetic retinopathy, but the American Diabetes Association says, “Cataract surgery has not been definitely demonstrated by recent studies to accelerate the progression of diabetic retinopathy, especially in the more recent era.”
Glaucoma is an eye disease caused by increased pressure in the eye. The increase in pressure can affect the optic nerve and therefore increase the risk of vision loss. Primary open angle glaucoma (POAG) is the most common type of glaucoma in people with diabetes.
Diabetic Macular Edema (DME)
DME can occur at any stage of diabetic retinopathy and can cause distortions of images and reduce the clarity and sharpness of objects that are seen. It occurs when there is swelling or thickening of the macula due to an accumulation of fluid. DME is the most common cause of vision loss in people with diabetic retinopathy.
When to See a Doctor
All people with diabetes are encouraged to get dilated eye exams by an ophthalmologist or optometrist. People with established retinopathy should be seen by an eye doctor who understands and specializes in the management and treatment of diabetic retinopathy.
When and how often you should go to the eye doctor will depend on the type of diabetes you have, when you were diagnosed, your glycemic control, if you are having symptoms, and your eye health.
If you have been recently diagnosed with type 2 diabetes, the American Diabetes Association recommends that you get an initial dilated eye and comprehensive eye exam by an ophthalmologist or optometrist at the time of diagnosis.
If there is evidence of retinopathy, you will likely need an eye exam yearly thereafter or more often, depending on the severity of the disease. If there is no evidence of retinopathy for one or more annual eye exams, then exams every two years will be considered.
Adults with type 1 diabetes should have an eye examination within five years of diagnosis. Children with type 1 diabetes should ask their doctor when and how often they need an eye exam.
People with preexisting diabetes (type 1 or 2) who are planning to get pregnant should discuss eye health with their doctors, and they should have an eye exam before getting pregnant or within the first trimester of pregnancy.
It is estimated that regular follow-up and early detection and treatment of retinopathy enable the prevention of up to 98% of visual loss due to retinopathy.
If you are having any symptoms of visual impairment, such as an increase in blurriness, flashes of light, cloudiness, or vision loss, you should contact your doctor right away for immediate care.
Retinal detachment is considered a medical emergency. You should see your doctor or head to the emergency room if you have any symptoms. Early treatment could save vision loss.
A Word From Verywell
Diabetic retinopathy is a complication of diabetes that can be treated effectively with early detection, screening, and treatment. People with diabetes can potentially prevent or delay retinopathy by maintaining adequate blood sugar and lipid levels, and blood pressure.
There are different stages of retinopathy. In the earliest stage, you may not experience any symptoms. Therefore, it is extremely important to have your dilated eye exams and routine checkups when advised by your physician.