Diabetic retinopathy is the most common serious eye complication of diabetes — and the leading cause of blindness in working-age adults in the United States, according to the CDC. The difficult part: it rarely causes noticeable symptoms until damage is already significant. The reassuring part: when caught early, its progression can be slowed or stopped entirely.
What Is Diabetic Retinopathy?
Diabetic retinopathy occurs when persistently high blood sugar damages the tiny blood vessels inside the retina — the light-sensitive layer at the back of the eye. Over time, these vessels may swell, leak fluid, bleed, or grow new abnormal vessels that are fragile and prone to rupturing. The result is progressively impaired vision and, if left untreated, blindness.
The longer a person has diabetes and the less controlled their blood sugar, the higher their risk of retinopathy. An A1C consistently above 8% over many years is strongly associated with retinopathy progression. According to the ADA 2024 Standards of Care, all adults with type 2 diabetes should have a comprehensive dilated eye exam at diagnosis and annually thereafter (or every 1 to 2 years in people with low risk and well-controlled diabetes).
The Four Stages of Diabetic Retinopathy
Stage 1: Mild Non-Proliferative Diabetic Retinopathy (NPDR)
Tiny balloon-like swellings develop in the walls of retinal blood vessels, called microaneurysms. These may leak small amounts of fluid. At this stage, vision is usually completely normal and there are no symptoms. The condition is detectable only through an eye exam.
Stage 2: Moderate NPDR
More blood vessels become blocked or damaged. The macula — the central area of the retina responsible for sharp vision — may begin to swell (this is called macular edema), causing some blurring. Spotty areas of the retina lose their blood supply.
Stage 3: Severe NPDR
Large areas of the retina are deprived of blood. The retina sends chemical signals to grow new blood vessels to compensate. No abnormal new vessels have grown yet, but the risk of progression is high. The ADA classifies severe NPDR as a high-risk state requiring close monitoring and often prompt treatment.
Stage 4: Proliferative Diabetic Retinopathy (PDR)
Abnormal, fragile new blood vessels grow on the retinal surface and into the vitreous gel inside the eye. These vessels bleed easily, causing floaters, dark spots, or sudden vision loss. Scar tissue can form and pull the retina away from the back of the eye — a tractional retinal detachment — leading to severe, permanent vision loss if not treated urgently.
Diabetic Macular Edema: A Related Condition
Diabetic macular edema (DME) is swelling of the macula — the central part of the retina that enables reading, recognizing faces, and seeing fine detail. DME can develop at any stage of retinopathy and is the most common cause of vision loss directly attributable to diabetic eye disease. It causes blurring or waviness in central vision and, in some cases, colors appearing washed out or distorted.
Symptoms of Diabetic Retinopathy
The central challenge with diabetic retinopathy is that early and moderate stages produce no symptoms at all. By the time symptoms appear, significant damage has typically already occurred. Warning signs to watch for include:
- Blurred or fluctuating vision
- Seeing floaters — dark strings, spots, or cobwebs drifting across your field of vision
- Dark or empty areas in central vision
- Colors appearing faded or washed out
- Difficulty seeing clearly at night
- Sudden, severe vision loss
How Is Diabetic Retinopathy Diagnosed?
Diagnosis is made through a dilated eye examination. Your eye doctor uses drops to widen your pupils and directly examines the retina. Additional tests may include:
- Fluorescein angiography: A dye is injected into the arm and photographs are taken as it flows through the retinal vessels, revealing leaks, blockages, and areas of abnormal growth.
- Optical coherence tomography (OCT): Cross-sectional images of the retina reveal swelling (macular edema) and structural changes in precise, millimeter-level detail.
- OCT-A (angiography): Maps blood flow in the retina without dye injection, useful for tracking progression.
The ADA recommends that people newly diagnosed with type 2 diabetes — including those who show prediabetes warning signs before diagnosis — have a baseline dilated eye exam, since retinopathy can occasionally be present at the time of diagnosis.
Treatment Options
Blood Sugar and Blood Pressure Control
The most powerful intervention is controlling blood sugar and blood pressure. Landmark trials (DCCT, UKPDS) established that intensive glucose control reduces the risk of developing retinopathy by up to 76% and slows progression significantly. The ADA 2024 target of an A1C below 7% is associated with substantially lower retinopathy risk. Maintaining blood pressure below 130/80 mmHg also slows retinopathy progression independently of blood sugar.
Anti-VEGF Injections
Anti-VEGF drugs — ranibizumab (Lucentis), aflibercept (Eylea), bevacizumab (Avastin, used off-label), and faricimab (Vabysmo) — are now the first-line treatment for DME and for PDR. Injected directly into the vitreous gel of the eye, they block the chemical signal that drives abnormal vessel growth and reduce retinal swelling. Treatments are monthly or bimonthly at first, often spacing out as the retina stabilizes.
Laser Photocoagulation
Laser treatment has been used for decades. For PDR, panretinal photocoagulation (PRP) targets peripheral retinal tissue to reduce oxygen demand that drives abnormal vessel growth. For focal DME, laser can seal leaking microaneurysms. While partly superseded by anti-VEGF injections for DME, laser remains a key tool for severe PDR.
Vitrectomy
For advanced PDR with significant vitreous hemorrhage or tractional retinal detachment, vitrectomy is a surgical procedure that removes the blood-filled vitreous gel and fibrous scar tissue, allowing the retina to reattach. Visual outcomes depend heavily on how quickly the procedure is performed after detachment.
Risk Factors for Diabetic Retinopathy
- Poor blood sugar control — the primary modifiable risk factor (ADA, CDC)
- Long duration of diabetes
- High blood pressure
- High cholesterol and triglycerides
- Smoking
- Pregnancy with pre-existing diabetes
- Kidney disease (diabetic nephropathy and retinopathy frequently co-occur)
Women with type 2 diabetes who become pregnant may experience accelerated retinopathy progression, as seen in research on gestational diabetes complications, and should have dilated eye exams in each trimester. For people showing early signs of type 2 diabetes, prompt diagnosis and treatment may prevent retinopathy from developing at all.
Prevention: What You Can Do Starting Today
- Keep A1C below 7% — every percentage point above 7% roughly doubles the risk of retinopathy progression over time (ADA 2024).
- Control blood pressure — target below 130/80 mmHg.
- Quit smoking — smoking accelerates microvascular damage across the body.
- Get annual dilated eye exams — or validated retinal photography; this is the cornerstone of prevention.
- Manage lipids — high triglycerides are an independent risk factor for DME.
I skipped my eye appointments for three years because I could see fine. By the time I went back, I was already at stage 3. I had laser treatment and anti-VEGF injections. My vision stabilized — but I wish I had never missed those appointments.
In Short
Diabetic retinopathy progresses silently through four stages before causing vision loss. The CDC estimates 1 in 3 adults with diabetes has some degree of retinopathy. The best protection is a combination of tight blood sugar control (A1C below 7%, per the ADA 2024 Standards of Care), blood pressure management, and annual dilated eye exams. When detected early, treatment with anti-VEGF injections, laser, or surgery can preserve vision in most cases. What you cannot feel, only an exam can catch.
Frequently Asked Questions
What is diabetic retinopathy?
Diabetic retinopathy is damage to the blood vessels of the retina caused by persistently high blood sugar. It progresses through four stages — from mild non-proliferative to proliferative — and, if untreated, leads to blindness. It is the leading cause of vision loss in working-age adults in the US (CDC).
Can diabetic retinopathy be reversed?
Early stages (mild to moderate NPDR) may partially improve with tight blood sugar control. Advanced stages cannot be reversed, but progression can be halted or significantly slowed with anti-VEGF injections, laser treatment, or surgery. The key is early detection.
How often should people with diabetes get eye exams?
The ADA recommends a dilated eye exam at the time of type 2 diabetes diagnosis, then annually. If retinopathy is absent and A1C is well controlled, every 1 to 2 years may be acceptable with your doctor's agreement. If any retinopathy is detected, exams every 3 to 6 months are typically needed.
What are the first signs of diabetic retinopathy?
In early stages, there are usually no symptoms at all. The first detectable changes — microaneurysms and microhemorrhages — are visible only on an eye exam. When symptoms do appear (blurred vision, floaters, dark spots), the disease has usually reached a moderate or advanced stage.
Is diabetic retinopathy painful?
No. Diabetic retinopathy is typically painless, even in advanced stages — another reason it so often goes undetected without regular screening. Eye pain with diabetes should prompt immediate evaluation for other conditions such as neovascular glaucoma, which can be a late complication of PDR.
