Diabetes and high glucose levels in the blood affect almost every organ in the body, including the eyes. One of the most serious conditions in the eye, caused by diabetes, is proliferative diabetic retinopathy.
These conditions are known as diabetic eye complications and include diabetic macular edema, cataracts, and glaucoma.
According to the CDC, one in three diabetics has diabetic retinopathy. Professionals from the CDC also state that the incidence of diabetic retinopathy in the USA is very high – around 4.2 million diabetics have some stage of diabetic retinopathy.
Let’s explore all the elements that one needs to know about proliferative diabetic retinopathy, from how and why it develops to all the ways it could be treated.
What Is Proliferative Diabetic Retinopathy?
PRD or proliferative diabetic retinopathy is a late-stage complication of diabetic retinopathy. Diabetic retinopathy occurs when high blood sugar levels damage the blood vessels of the retina. This condition is the late stage of diabetic retinopathy.
On the other hand, non-proliferative diabetic retinopathy is an early stage, and it occurs when there is vascular damage in existing blood vessels in the retina.
The damage that occurs to the vessels leads to poor oxygen supply to the retina. The eyes, in an attempt to restore this supply, begin to proliferate and form new blood vessels. Unfortunately, these blood vessels aren’t strong structurally.
That is why most of the time, they leak blood and fluid, which can include creating scar tissue in the eye, and bleeding into the vitreous humor. In extreme cases, it causes the retina to detach from the back of the eye.
Symptoms and Signs
Proliferative diabetic retinopathy is a silent condition, meaning that in the early stages, people do not experience or notice any symptoms. This leads to a delayed diagnosis and treatment.
Depending on where the bleeding occurs, there are two types of hemorrhages:
- Vitreous hemorrhage – bleeding into the vitreous humor, which affects around 14.3% of diabetics with PDR.
- Preretinal hemorrhage – bleeding in front of the retina, which occurs in 8.6% of diabetics with PDR
When the condition begins to worsen, people may experience the following signs and symptoms:
- Floaters – visual disturbances that look like dark spots or strings. These are often small amounts of blood present in the vitreous humor.
- Flashes of light
- Blurred vision and visual field loss
- Sudden profound vision loss – when a large hemorrhage occurs in the eye
- Persistent eye pain – a rare symptom due to increased ocular pressure and other issues present.
If PDR is not diagnosed and treated on time, these symptoms lead to irreversible damage to the blood vessels and irreversible blindness.
Causes of Proliferative Diabetic Retinopathy
The root cause of PDR is poorly controlled diabetes, whether that is type 1 or type 2.
Because of the constant hyperglycemia, the retina releases VEGF, which is a vascular endothelial growth factor, to promote new blood vessel growth, a condition called neovascularization. Even though it seems like a protective measure, these vessels are often fragile and prone to rupture.
Aside from high glucose levels in the blood, other factors can lead to the progression of proliferative diabetic retinopathy, such as:
- High blood pressure
- High cholesterol levels
- Kidney disease
- Smoking
The risk is also increased during pregnancy in diabetic patients, with 6.1% of pregnant diabetics having PDR early in their pregnancy, which can rise to 8.2% by the time they have to deliver. PDR occurs only in women who were diabetic before becoming pregnant, but not in women who develop gestational diabetes during pregnancy. Women with gestational diabetes rarely develop a mild early-stage form of NPDR, which also rarely goes into PDR.
Diagnosis and Treatment
The damage to the retinal blood vessels is irreversible, which makes proliferative diabetic retinopathy not curable. It is treatable only when caught early. With proper care, most people maintain functional vision.
Diagnosis
To diagnose proliferative diabetic retinopathy, patients need to visit their ophthalmologists and get a comprehensive eye examination. This examination requires the doctor to apply special drops to widen the pupils to thoroughly examine the retina.
Ophthalmologists look for signs that point to PDR, such as:
- Scar tissue
- Neovascularization
- Retinal bleeding
Depending on the changes in the eye, ophthalmologists may recommend additional tests, such as:
- OCT (optical coherence tomography) to view other structural changes in the retina and vitreous humor.
- Fluorescein angiography (injecting dye in the retinal bloodstream) to detect vascular abnormalities.
The American Academy of Ophthalmology has recommendations on how often a patient should be screened:
- 5 years after diagnosis in type 1 diabetics
- At the time of diagnosis in type 2 patients
After that, all patients who do not have retinopathy should have annual ophthalmology check-ups.
Treatment
The treatment of proliferative diabetic retinopathy depends on the severity of the condition and the individual needs of the patients. Most of the available treatment involves managing and blocking VEGF, the growth factor that stimulates the growth of new blood vessels.
There are several treatment options available for managing PDR, such as:
- Anti-VEGF Injections – these medications block the growth factor VEGF, which stimulates the growth of new blood vessels. Injections are administered monthly and require ongoing check-ups and follow-ups.
- Panretinal Photocoagulation – laser treatment that targets the poorly oxygenated areas of the retina and destroys them. That leads to reduced VEGF production. This type of treatment is mostly used on patients with moderate to severe PDR.
- Vitrectomy – in severe cases, this surgical procedure removes the vitreous gel in the eye and replaces it with a clear solution to preserve vision.
Complications
If PDR is left untreated and progresses, the complications that occur can be severe. Aside from sudden vision loss due to blood in the visual field or retinal detachment, other complications are:
- Neurovascular glaucoma – a rare complication when the new vessels block the eye’s drainage system.
- Chronic ischemia – the prolonged lack of oxygen leads to permanent retinal cell death.
- Nerve damage – caused by neurovascular glaucoma and chronic ischemia, nerve damage occurs.
All of these complications and their progress lead to irreversible loss of vision and blindness, but with timely intervention and proper therapy, these severe complications can be reduced by 95%.
Can Diabetic Retinopathy Be Reversed?
The reversibility of diabetic retinopathy depends on the severity and the stage of the disease. There are five stages, which we’ve compiled in this table. The diabetic retinopathy stages include:
| Stage | Symptom | Is it reversible? |
|---|---|---|
| Mild Non-Proliferative Diabetic Retinopathy | None | ? |
| Moderate Non-Proliferative Diabetic Retinopathy | Mild visual changes | Possible, depending on the time of diagnosis |
| Severe Non-Proliferative Diabetic Retinopathy | More noticeable vision problem | X |
| Severe Proliferative Diabetic Retinopathy (PDR) | Floaters, vision loss, dark spots | X |
| Diabetic Macular Edema (DME)* | Blurred central vision, difficulty remembering and recognizing faces | X |
*DME is considered a stage by some authors and a complication by others; in this article, we decided to consider it a stage.
Early stages of diabetic retinopathy can often be partially reversed or stabilized if diagnosed in time. On the other hand, advanced stages can be treated and controlled, but not fully reversed.
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Prevention
The best strategy for preventing proliferative diabetic retinopathy and other conditions that stem from diabetes is to keep blood sugar levels within range. In order to keep these levels in the normal ranges, taking medication is not enough. Other ways to manage it are:
- Healthy diet
- Exercising
- Regular check-ups
Patients should also keep their blood pressure and cholesterol levels normal, which also reduces the chance of developing eye disease. Other prevention methods are quitting smoking, for those who smoke, and visiting the ophthalmologist regularly.
Conclusion
Proliferative diabetic retinopathy is a serious complication of diabetes. It often develops without warning and could lead to vision loss, but it is not a life sentence. Many diabetics with PDR still live their normal day-to-day lives with small changes in their habits to delay the advances of the disease.
It cannot be fully reversed in more advanced stages, but having regular checkups and taking all needed measures can slow the progress.
It starts by managing diabetes with a combination of medicine, diet, exercise, and other healthy habits. All together, these are the most powerful tools in preventing and delaying PDR.
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Original Publish Date: 12/7/2023 – Updated 7/8/2025
