What Are the Stages 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 

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:

• Duration of diabetes
• Poor glycemic control
• High blood pressure (hypertension)
• Other microvascular complications, such as diabetes-related nephropathy and neuropathy
• High blood lipids (fats) (dyslipidemia)
• Pregnancy, which can temporarily increase the risk and progression

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
  • Checks the pressure inside the eye (intraocular pressure)
• 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

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

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