What Is Proliferative Diabetic Retinopathy?

Proliferative diabetic retinopathy (PDR) is the advanced stage of diabetic retinopathy, an eye disease related to diabetes (a condition in which blood sugar levels are high). In proliferative diabetic retinopathy, new blood vessels grow in the retina, the light-sensing layer at the back of the eye. It's a serious condition and can lead to vision loss.

Taking precautions before you reach this stage of diabetic retinopathy is essential to prevent this potentially sight-threatening condition.

This article will highlight how proliferative diabetic retinopathy differs from non-proliferative diabetic retinopathy (NPDR), the symptoms and causes, how it is diagnosed and treated, and what to know about your prognosis and possible complications.

NPDR vs. PDR

There are two forms of diabetic retinopathy: non-proliferative diabetic retinopathy or proliferative diabetic retinopathy.

A key difference between the two is whether new blood vessels are being made in the retina. With NPDR, blood vessels have begun to leak fluid onto the retina, causing swelling. But these are not new blood vessels; they are existing ones that have been damaged by too much sugar in the blood.

Diabetic retinopathy can also cause some blood vessels to shut down. When there isn't enough blood supply to the retina, a signal is sent out that spurs the development of new blood vessels. But these are abnormal and prone to leaking. This advanced stage, where such blood vessels develop, is known as PDR.

The bleeding from these abnormal new vessels can lead to scarring on the retina. Ultimately, the scarring can lead to retinal detachment, in which the retina separates from the back of the eye. In turn, this can lead to vision loss.

Abnormal new vessels can also grow in the front of the eye and block the normal drainage of fluid, leading to elevated eye pressure (neovascular glaucoma). Elevated eye pressure can then cause permanent damage to the optic nerve, which can also contribute to permanent vision loss.

Preventing PDR

Preventing proliferative diabetic retinopathy centers on getting diabetes under control and monitoring your eyes for the progression of diabetic retinopathy.

It can help to take the following measures:

• Regularly see an eye care provider for a dilated (expanded pupil) exam when recommended.
• Follow a healthy eating plan that's low in sugar.
• Engage in regular physical activity.
• Undergo A1C blood sugar monitoring to see what your levels have been over three months.
• Lower your blood pressure levels (a risk factor for diabetic retinopathy).
• Reduce high cholesterol, another risk factor,

Symptoms

With diabetic retinopathy, early on, you will likely have no symptoms. However, that will change over time. Symptoms you may develop as the disease progresses include:

• Blurring of vision
• Double vision
• Seeing floaters or dark spots
• Feeling pressure in one or both eyes or experiencing pain
• Seeing rings around lights at night
• Seeing flashes of light
• Noticing blank spots in your vision
  

Diabetic Retinopathy

Causes

In type 1 diabetes, type 2 diabetes, and gestational diabetes, high blood sugar damages the small blood vessels in your eye and throughout the body. This can lead to blockage of the blood vessels and leaking.

Proliferative diabetic retinopathy occurs if your retina is not receiving enough blood due to blocked blood vessels. This sends signals for new blood vessels to develop on its surface. However, these new blood vessels tend to be delicate (with thin walls) and leak.

When these blood vessels leak, they can cause scarring and lead to severe vision loss or blindness.

Diagnosis

To examine your eyes for proliferative diabetic retinopathy, your eye care provider will dilate (expand) your pupil at the center of your eye. This enables them to see the structures inside your eye,

To observe changes in your retinal blood vessels, they will perform fluorescein angiography. They will inject a yellow dye (fluorescein) into a vein (probably in your arm). They will take images of the retinal blood vessels using a special camera. This will show if blood vessels are leaking and whether new abnormal blood vessels are forming.

The eye care provider may also do fluorescein angiography to check if the retina is swollen and to measure it.

A newer type of angiography, optical coherence tomography (OCT) angiography is a noninvasive technology that provides three-dimensional imaging of the retinal blood vessels and structures. It can measure the swelling of the macula in the retina.

Treatment

If you have proliferative diabetic retinopathy, you should be under the care of an ophthalmologist (physician specializing in eye health) who is experienced in treating this condition. Treatments may include the following:

• Laser photocoagulation treatment: A laser scatter approach hinders the growth of new vessels. Hundreds of laser burns are created across the retinal surface. The laser is not used in the central retina, which is responsible for central vision and sharp acuity.
• Anti-vascular epithelial growth factor (VEGF) injections: Anti-VEGF injections block the effects of vascular endothelial growth factor, a protein that spurs the growth of new blood vessels. This may even help to shrink some of the new blood vessels that have already developed.
• Vitreous gel removal (vitrectomy): If you experience a vitreous hemorrhage (bleeding in the clear fluid that fills the eye) or a retinal detachment, your ophthalmologist may suggest removing the vitreous gel and replacing it with a clear substitute. They can also remove some scar tissue from the retina.

Prognosis

Your outcome with PDR will depend on the condition of your retina. Those who receive treatment before severe damage is done to the retina have a good chance of keeping their vision. So, it is important that you get frequent checkups to make sure that your proliferative diabetic retinopathy remains under control.

Complications

One complication to be concerned about with PDR is retinal scarring, which can occur when blood leaks onto the area from abnormal blood vessels. These scars can shrink and tug on the retina, distorting vision.

If they tug hard enough, they can cause a retinal detachment, when the light-sensitive retina pulls away from the back of the eye. A retinal detachment is extremely serious. If this is not promptly treated, vision loss can be permanent.

High blood sugar can also contribute to the formation of a cataract, in which the clear lens of the eye becomes clouded. Neovascular glaucoma can also develop. This can damage the optic nerve and lead to vision loss.

Summary

Those with proliferative diabetic retinopathy are in the more advanced stage of the disease. The difference between the proliferative and non-proliferative stages is that abnormal new blood vessels have begun forming on the retina in this more advanced stage.

This occurs when regular blood vessels begin to close off due to high sugar levels. In turn, the retina sends a signal for new blood vessels to develop. Such new blood vessels can be seen with diagnostic techniques such as fluorescein angiography.

Treatments for proliferative diabetic retinopathy include laser photocoagulation, anti-VEGF injections, and sometimes the removal of the vitreous gel.

A Word From Verywell

Proliferative diabetic retinopathy is a serious condition. But if this is promptly treated before damage to the retina has had a chance to occur, this condition can be managed and sight maintained. See an eye care specialist as soon as you notice vision changes.