Diabetic retinopathy is an eye disease that affects people living with diabetes. It develops when high blood sugar damages the tiny blood vessels in the retina. This causes a variety of symptoms like blurry vision and vision loss.

This progressive disease may lead to irreversible vision loss, so it’s important to have regular eye exams. A doctor can then diagnose the condition early and slow its progression.

Glucose, or blood sugar, is a main source of energy — yet too much circulating in the blood can be harmful to the body.

Typically, the pancreas releases the hormone insulin, which helps cells absorb glucose for energy. In the case of diabetes, though, the body doesn’t make enough insulin or doesn’t use it properly. This causes glucose to accumulate in the blood.

Consistent levels of high blood sugar can affect different parts of the body, including the eyes.

Diabetic retinopathy doesn’t only weaken or damage the blood vessels in the eye. It can also cause the development of new abnormal blood vessels in the retina.

Diabetic retinopathy is a progressive eye disease classified by two types and four stages.

The two types are nonproliferative and proliferative. Nonproliferative refers to early stages of the disease, while proliferative is an advanced form of the disease.

Stage 1: Mild nonproliferative diabetic retinopathy

This is the earliest stage of diabetic retinopathy, characterized by tiny areas of swelling in the blood vessels of the retina. These areas of swelling are known as micro aneurysms.

Small amounts of fluid can leak into the retina at the stage, triggering swelling of the macula. This is an area near the center of the retina.

Stage 2: Moderate nonproliferative diabetic retinopathy

Increased swelling of tiny blood vessels starts to interfere with blood flow to the retina, preventing proper nourishment. This causes an accumulation of blood and other fluids in the macula.

Stage 3: Severe nonproliferative diabetic retinopathy

A larger section of blood vessels in the retina become blocked, causing a significant decrease in blood flow to this area. At this point, the body receives signals to start growing new blood vessels in the retina.

Stage 4: Proliferative diabetic retinopathy

This is an advanced stage of the disease, in which new blood vessels form in the retina. Since these blood vessels are often fragile, there’s a higher risk of fluid leakage. This triggers different vision problems such as blurriness, reduced field of vision, and even blindness.

Diabetic retinopathy doesn’t usually cause symptoms during the nonproliferative stages, so it’s possible to have it and not know it. This is because blood vessels don’t always leak in these stages.

Many people don’t have symptoms until the disease progresses to proliferative diabetic retinopathy.

However, an eye examination by an eye care specialist or ophthalmologist can detect diabetic retinopathy in its earlier stages, before symptoms become apparent.

Symptoms of proliferative diabetic retinopathy include:

  • an increased number of eye floaters
  • blurry vision
  • distorted vision
  • poor night vision
  • loss of vision
  • decreased field of vision
  • change in colors

Be mindful, too, that diabetic retinopathy symptoms usually affect both eyes at the same time.

To diagnose diabetic retinopathy, your doctor may complete a comprehensive eye examination. This involves measuring:

  • visual acuity
  • eye muscle movement
  • peripheral vision
  • depth perception
  • curvature of the cornea

Your doctor will likely also dilate your eye to examine your optic nerve and retina using special eye drops.

Doctors can also diagnose diabetic retinopathy with fluorescein angiography, which checks for abnormal blood vessel growth or leakage.

They’ll inject a yellow dye into a vein in your arm, allowing the dye to travel through your blood vessels. A special camera takes images of the dye as it travels through the blood vessels in your retina.

Diabetic retinopathy may lead to irreversible vision loss, but it is treatable. Treatment starts with managing blood sugar and diabetes. This includes taking diabetes medication as directed, watching your diet, and increasing physical activity.

Keeping blood sugar within a healthy range can slow the progression of vision loss.

Other treatments will depend on the stage or extent of the disease. If caught very early — before damage to the retina occurs — blood sugar management might be the only necessary treatment. Your doctor will continue to monitor your eyes, though, to ensure the disease doesn’t progress.

If you’re in a nonproliferative stage but experience some eye damage, treatment options might include:

  • Laser surgery. Laser surgery, called photocoagulation, reduces the drive for abnormal blood vessels and swelling in the retina.
  • Eye medications. A steroid injection in the eye can stop inflammation and prevent the formation of new blood vessels. You might also be a candidate for anti-VEGF medication, which can reduce swelling in the macula and improve vision. Doctors administer both treatments as an injection in the eye.
  • Vitrectomy. If you have proliferative diabetic retinopathy, you might need an eye surgery called vitrectomy. This surgery treats problems with the retina and vitreous, a jellylike substance in the middle of the eye. The surgery can remove scar tissue, blood or fluid, and some of the vitreous gel so light rays can focus properly on the retina. At the same time, traction in the retina or retinal detachments can be corrected.

Preventing diabetic retinopathy starts with managing blood sugar.

This involves managing diabetes with medication, balanced eating habits, and regular physical activity. You should also monitor your blood sugar on a regular basis and speak with your doctor if your levels are difficult to manage.

A healthy diet consists of:

  • low glycemic carbohydrates
  • vegetables
  • fruits
  • whole grains
  • legumes
  • low fat dairy
  • healthy fats (avocados and nuts)
  • heart-healthy fish, such as salmon and tuna

Diabetes management may also involve other changes. This can include managing your blood pressure and cholesterol and avoiding tobacco.

Diabetic retinopathy isn’t the only complication of diabetes. Blood sugar levels outside of a healthy range can cause other long-term issues, such as:

  • heart disease
  • kidney damage
  • nerve damage
  • Alzheimer’s disease
  • foot damage
  • depression
  • skin conditions

It may also lead to other conditions involving significant vision loss or blindness, such as:

  • Macular edema: an accumulation of fluid in the center of the retina, causing swelling and distorted vision
  • Retinal detachment: a condition where the retina pulls away from supportive tissue in the eye
  • Neovascular glaucoma: a type of secondary glaucoma where new blood vessels grow on the angle of the eye, preventing the drainage of eye fluids
  • Vitreous hemorrhage: new blood vessels bleed and completely block vision

If you have diabetes, make an appointment to see an eye care specialist such as an ophthalmologist at least once a year, or as often as your doctor recommends.

You should also see your doctor if your glucose level remains high despite medication and other changes, or if you notice any changes in vision, even if they are subtle.

Diabetic retinopathy is a potentially serious eye disease that can result in permanent distorted vision or loss of vision. Any changes in vision, such as blurriness, poor night vision, and an increase of eye floaters, should prompt a trip to the eye doctor.

Speak with your eye care specialist to diagnose any possible eye conditions. Although diabetic retinopathy isn’t reversible, it is treatable.