What Are the Stages of Diabetic Retinopathy?

Reviewed on 4/12/2021

An eye condition that can potentially lead to blindness, diabetic retinopathy typically occurs in people who do not control their blood sugar. There are four stages of diabetic retinopathy, which are categorized depending on the severity of symptoms.
An eye condition that can potentially lead to blindness, diabetic retinopathy typically occurs in people who do not control their blood sugar. There are four stages of diabetic retinopathy, which are categorized depending on the severity of symptoms.

Diabetic retinopathy is an eye condition that affects people with diabetes and can lead to vision loss and blindness. It occurs most often in diabetics who do not keep their blood sugar well-controlled.

The four stages of diabetic retinopathy include the symptoms outlined in the table below.

The Four Stages of Diabetic Retinopathy
Stage Symptoms
Background retinopathy (mild nonproliferative retinopathy)
  • Small bulges (microaneurysms) in the tiny blood vessels of the back of the eye (retina) appear and may cause the vessels to leak tiny amounts of blood 
  • Vision is not affected at this stage 
  • Patients do not need treatment but need to monitor blood sugar, cholesterol levels, and blood pressure to prevent the problem from worsening
Pre-proliferative retinopathy (moderate nonproliferative retinopathy)
  • The tiny blood vessels of the retina swell, blocking blood flow which can damage the retina
  • Blood and other fluids build up in the small central part of the retina (macula), causing diabetic macular edema
  • Vision may start to be affected
Proliferative retinopathy (severe nonproliferative retinopathy)
  • New blood vessels and scar tissue form on the retina
  • Blood vessels can become obstructed completely (macular ischemia), which can lead to blurred vision with dark spots in the field of vision (“floaters”)
  • Can lead to retinal detachment
  • There is an increased risk of vision loss at this stage
  • Treatment at this stage may stabilize vision but any vision lost cannot be restored
Proliferative diabetic retinopathy
  • An advanced stage in which there is growth of abnormal and fragile new blood vessels 
  • These blood vessels have fragile walls and can leak a considerable amount of blood, causing severe vision loss and blindness

What Are Symptoms of Diabetic Retinopathy?

Diabetic retinopathy may not cause any symptoms in the early stages. Once symptoms occur, it may be too late to restore any vision lost. It is important for people who have diabetes to be screened for the condition early and routinely to protect their eyes and prevent vision loss.

When symptoms of diabetic retinopathy occur, they may include:

  • Blurred vision
  • Patchy vision
  • Eye pain 
  • Eye redness 
  • Dark spots in the field of vision (“floaters”)
  • Trouble seeing things that are at the center of focus when reading or driving
  • Difficulty telling colors apart
  • Gradually worsening vision
  • Sudden vision loss 

What Causes Diabetic Retinopathy?

Diabetic retinopathy is caused by high blood sugar (hyperglycemia) due to diabetes. In patients who do not manage their blood sugar, over time, high blood sugar can damage the retina

Sugar blocks the tiny blood vessels that go to the retina, causing them to swell and leak fluid or bleed. To compensate, the eyes grow new blood vessels that don’t work properly and vessels leak or bleed easily. 

Risk factors for the development and progression of diabetic retinopathy include:


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How Is Diabetic Retinopathy Diagnosed?

People with diabetes should have their eyes checked regularly. Once diabetic retinopathy is diagnosed, patients may need to have more frequent eye exams, up to several times per year. 

Diabetic retinopathy is diagnosed with two main tests:

  • Dilated eye exam
    • Eye drops are administered dilate the pupils 
    • The doctor looks at the back of the eye (the retina), the part of the eye damaged by diabetic retinopathy
  • Digital retinal imaging
    • A technician takes pictures of the eye with a special camera

Other tests may be indicated, such as:

  • Visual acuity test
    • An eye chart test to measure vision at various distances
  • Tonometry
  • Ophthalmoscopy
    • The retina is examined using a special magnifying glass
  • Fluorescein angiography
    • Organic dye is injected into the bloodstream to show blood vessels in the eye 
    • Images are taken with a special camera that can indicate whether blood vessels are leaking or no longer supplying areas of retina
  • Optical coherence tomography
    • Light waves are used to create detailed images of the retina

What Is the Treatment for Diabetic Retinopathy?

Mild diabetic retinopathy does not always need to be treated. People who have diabetic retinopathy need to keep blood sugar and blood pressure levels well-managed to prevent the condition from getting worse.

Treatment for diabetic retinopathy may include:

  • Photocoagulation
    • Laser surgery that seals or destroys leaking or growing blood vessels in the retina
  • Medications
    • Injected into the vitreous humor 
    • May be used alone or along with other treatments
    • May help slow or reverse the disease
      • Anti-VEGF drugs
      • Corticosteroids
  • Vitrectomy
    • A type of surgery that removes blood from the part of the eye called the vitreous humor

What Are Complications of Diabetic Retinopathy?

Complications of diabetic retinopathy may include: 

  • Diabetic macular edema (DME)
    • Blood vessels in the retina leak fluid, causing swelling in the macula (a part of the retina)
    • Vision becomes blurred because of the extra fluid in the macula
    • About half of people with diabetic retinopathy will develop DME
  • Neovascular glaucoma
    • Abnormal blood vessels grow out of the retina and block fluid from draining out of the eye, which causes a type of glaucoma
  • Retinal detachment
    • Scars can form in the back of the eye and pull the retina away from the back of the eye

How Do You Prevent Diabetic Retinopathy?

Patients with diabetes can reduce the risk of developing diabetic retinopathy by keeping blood sugar and blood pressure levels in check and having regular eye exams. Keeping cholesterol levels in the normal range may also help.

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Reviewed on 4/12/2021