Diabetes can cause a number of eye problems, but diabetic retinopathy, or DR, is the most common, and it can lead to vision loss or even blindness. In fact, diabetic retinopathy is the most common cause of new cases of blindness in working-age U.S. adults. Anyone with any type of diabetes is at risk of developing DR and its complications like diabetic macular edema—and the risk increases the longer you have diabetes.

Diabetic retinopathy happens inside your eyes and may not show symptoms until its later stages—but even though you can’t see it, there is something you can do about it. If you have diabetes, it’s very important to get your eyes checked at least once annually by an eye care professional, even if your vision seems normal.

Being examined by an eye doctor is the only way to determine if you have diabetic retinopathy. It’s also the only way to monitor diabetic retinopathy progression after you’ve been diagnosed. If you need treatment, you need to be referred to a retina specialist.

There’s a possibility that diabetic retinopathy can progress even if you’re managing your blood sugar levels, that’s why it’s important to go to your eye care specialist regularly. By performing some tests, your eye care specialist can find out what’s happening inside your eyes and, if needed, suggest actions that can be taken.


Watch a group of retina specialists discuss diabetic retinopathy and the importance of eye checkups


RETINOPATHY progresses

Diabetic retinopathy can be broken up into two stages: non-proliferative diabetic retinopathy, or NPDR (which can go from mild to moderate to severe), and proliferative diabetic retinopathy, or PDR.

Read on to learn, step by step, what these terms mean and how diabetic retinopathy can progress.

Non-Proliferative Diabetic Retinopathy (NPDR)

In the early stages of diabetic retinopathy, excess sugar levels start affecting the tiny blood vessels in the back of your eye. This part of the eye, called the retina, is what senses light and sends signals that your brain interprets as images.

At first, there might be no changes in your vision at all, but over time, NPDR can progress through mild, moderate, and severe stages. This happens as the blood vessels become increasingly swollen, and leak fluid or bleed, leaving the retina without enough oxygen or nutrients.

At this point, there still may be no changes in your vision—so there might not be warning signs you can notice on your own.

If NPDR is not slowed by treatment, bleeding and other changes can occur, and you may notice symptoms like blurriness around the edges of vision, difficulty reading, or seeing an increase in “floaters” in one or both eyes (it’s important to know that floaters can be signs of eye conditions not related to diabetes).

Proliferative Diabetic Retinopathy (PDR)

Over time, in response to the changes that NPDR causes, the body produces a substance called vascular endothelial growth factor, or VEGF. VEGF is thought to promote the growth of new blood vessels in the retina to try to get the blood flow it needs. These new vessels are not normal, though. They are fragile and easily damaged, and this adds to the swelling and leaking.

This advanced stage of diabetic retinopathy is called proliferative diabetic retinopathy because of the “proliferation”—or quick increase—of these new blood vessels. Visual symptoms like blurry vision or seeing dark spots are usually present at this stage.

PDR is very serious—and it often comes with vision loss.

It’s important to know that there are treatment options that may help slow down and even reverse some of the damage that may be happening inside the eyes.

Veins of a healthy eyeVeins of mild Non-Proliferative Diabetic RetinopathyVeins of Moderate Non-Proliferative Diabetic RetinopathyVeins of Severe Non-Proliferative Diabetic RetinopathyVeins of Proliferative Diabetic Retinopathy
DR progress
eye image horizon line

Healthy Eye

In healthy eyes, there is no swelling in the retina’s blood vessels and no leaking of fluids.

Mild Non-Proliferative Diabetic Retinopathy

During this stage, a few small bulges appear in the retina’s blood vessel walls. There are usually no visual symptoms.

Moderate Non-Proliferative Diabetic Retinopathy

In this stage, some blood vessels swell and start to leak. Also, a few blood vessels may develop an uneven shape, making them look like beads on a string. There are usually no visual symptoms.

Severe Non-Proliferative Diabetic Retinopathy

This stage has more leakage of blood into the retina, and a number of blood vessels supplying oxygen and nutrients to the eye can also become blocked. The body starts to signal the need to grow new blood vessels to help. Visual symptoms may occur.

Proliferative Diabetic Retinopathy

This stage happens when the retina starts growing new, fragile blood vessels that often bleed into the eye. Symptoms like dark spots are usually present, and permanent vision loss may occur.


Blood vessels are tubes that circulate blood within the body


The retina is the light-sensitive tissue lining the back of the eye


The tiny bulges in blood vessel walls are called microaneurysms (“my-crow-ann-yur-isms”)


Beginning stages of blood leaking into the retina


Many of the blood vessels in the retina show visible changes


Blood leaking into the retina is more severe


Bleeding in the space between the lens and the retina can cause changes in vision


Growth of new, fragile blood vessels

Now that you know what can happen inside your eyes when you have diabetic retinopathy, take a look at how its symptoms could affect your vision.