Non-Proliferative Diabetic Retinopathy (NPDR)

Non-proliferative diabetic retinopathy (NPDR) is the early stage of diabetic retinopathy, where diabetes damages the small blood vessels in the retina but abnormal new blood vessels have not yet grown. Most diabetics with retinopathy are in this stage. While vision may be normal, NPDR can progress to the more severe proliferative stage and can cause vision loss through macular edema. Because high blood pressure causes similar retinal changes, some patients wonder whether their findings are from diabetes or blood pressure — often, both contribute.

What Happens in NPDR

Blood Vessel Changes

High blood sugar damages retinal blood vessels:

• Vessel walls weaken
• Microaneurysms form (tiny bulges in vessel walls)
• Vessels leak fluid and blood
• Vessel closure occurs (capillary dropout)
• The retina becomes ischemic (oxygen-starved) in areas

What the Doctor Sees

Microaneurysms:

• Tiny red dots (earliest sign)
• Weak spots in vessel walls

Hemorrhages:

• Dot hemorrhages (small, round)
• Blot hemorrhages (larger, deeper)
• Flame hemorrhages (superficial, flame-shaped)

Hard Exudates:

• Yellow, waxy deposits
• From leaked lipids
• Often in rings around leaking areas

Cotton Wool Spots:

• White, fluffy areas
• Areas of retinal nerve fiber layer infarction
• Sign of ischemia

Venous Changes:

• Venous beading (varies in caliber)
• Venous loops

Intraretinal Microvascular Abnormalities (IRMA):

• Abnormal vessels within the retina
• Shunt vessels
• Sign of severe NPDR

Stages of NPDR

Mild NPDR

• At least one microaneurysm
• Earliest detectable stage
• Low risk of progression in short term
• Annual monitoring typically sufficient

Moderate NPDR

• More than just microaneurysms
• Hemorrhages, hard exudates in more than one quadrant
• Not meeting criteria for severe
• Monitoring every 6-9 months typically

Severe NPDR

Very Severe NPDR

• Two or more features of severe NPDR
• Very high risk of progression
• Consider treatment to prevent PDR

Symptoms

Often None

When Symptoms Occur

Symptoms usually indicate macular involvement:

• Blurred vision
• Difficulty reading
• Colors appear washed out
• Fluctuating vision (varies with blood sugar)

Diabetic Macular Edema (DME)

The Main Cause of Vision Loss in NPDR

Diabetic macular edema can occur at any stage of NPDR:

• Leaking blood vessels cause fluid to accumulate in the macula
• Macula is responsible for central, detailed vision
• Causes blurred and distorted central vision
• Treatable with injections

DME Can Occur With:

• Mild NPDR
• Moderate NPDR
• Severe NPDR
• Proliferative diabetic retinopathy

Diagnosis

Dilated Eye Exam

Essential for detection:

• Pupil dilation allows view of entire retina
• Direct visualization of retinal changes
• Staging of NPDR severity

Optical Coherence Tomography (OCT)

• Cross-sectional retinal images
• Detects macular edema (fluid in macula)
• Essential for management
• Non-invasive

Fluorescein Angiography

• Dye study showing blood vessel leakage and closure
• Helps determine extent of disease
• Guides treatment decisions
• Used selectively (not for all patients)

OCT Angiography

• Non-invasive vessel imaging
• Shows areas of non-perfusion
• Increasingly used for monitoring

Treatment

For NPDR Without Macular Edema

Primary Treatment: Systemic Control

No eye treatment is typically needed for NPDR without macular edema. Focus on:

• Blood sugar control—most important factor
• Blood pressure control—reduces progression risk
• Cholesterol management
• Smoking cessation
• Regular monitoring

For NPDR With Macular Edema

If macular edema is present, it should be treated regardless of NPDR severity:

Anti-VEGF Injections:

• Aflibercept (Eylea)
• Ranibizumab (Lucentis)
• Bevacizumab (Avastin, off-label)
• Very effective at reducing edema and improving vision

Steroid Options:

• Dexamethasone implant (Ozurdex)
• For patients who don't respond to anti-VEGF
• Risk of cataract, elevated eye pressure

Laser Photocoagulation:

• Focal/grid laser to leaking areas
• Less commonly used now
• May be adjunct to injections

For Severe NPDR

Options to Prevent Progression to PDR:

• Close monitoring (every 2-4 months)
• Consider anti-VEGF injections (can prevent progression)
• Consider panretinal photocoagulation if high-risk features
• Decision individualized based on:
  • Reliability of follow-up
  • Presence of high-risk features
  • Patient factors

Monitoring Schedule

NPDR Stage	Typical Follow-Up
Mild	12 months
Moderate	6-9 months
Severe	3-4 months
With macular edema	Monthly initially during treatment

Schedules are individualized based on patient factors

Prognosis

Progression Rates (Without Systemic Improvement)

• Mild NPDR: 5% progress to PDR in 1 year
• Moderate NPDR: 12-27% progress to PDR in 1 year
• Severe NPDR: ~50% progress to PDR in 1 year

With Good Systemic Control

• Progression can be significantly slowed
• Some features may improve
• Macular edema responds well to treatment

Key Factors in Prognosis

• Blood sugar control (HbA1c)
• Blood pressure control
• Duration of diabetes
• Baseline severity
• Adherence to follow-up

Prevention of Progression

What You Can Do

Blood Sugar Control:

• Target HbA1c <7% for most patients
• Work with your diabetes team
• Monitor blood sugar regularly
• Take medications as prescribed

Blood Pressure Control:

• Target <130/80 typically
• Take medications as prescribed
• Reduce salt intake
• Exercise as recommended

Other Measures:

• Don't smoke
• Control cholesterol
• Maintain healthy weight
• Regular exercise

The Evidence

Studies show:

• Intensive blood sugar control reduces progression by 50-70%
• Blood pressure control reduces progression by ~30%
• Combining both provides even greater protection

Frequently Asked Questions

If I have no symptoms, why do I need treatment or monitoring?

NPDR often has no symptoms, but it can progress to sight-threatening disease. Regular monitoring catches problems early when they're most treatable. Macular edema can develop at any time and responds best to early treatment.

Will my diabetic retinopathy get worse?

This depends largely on your blood sugar and blood pressure control. With good systemic control, progression can be significantly slowed or even stopped. Without it, progression is likely over time.

Do I need eye injections?

Not necessarily. Injections are only needed if you have macular edema causing vision problems. NPDR without macular edema is managed with systemic control and monitoring.

Can diabetic retinopathy improve?

Some features like mild macular edema can improve with better blood sugar control. More established changes usually don't reverse completely, but progression can be stopped.

How often do I need eye exams?

This depends on the severity of your NPDR. Mild disease may be monitored annually, while severe NPDR needs exams every few months. Your eye doctor will advise on your specific schedule.

Is NPDR serious?

While NPDR is the early stage and often doesn't affect vision, it indicates your diabetes is affecting your eyes. It can progress to vision-threatening disease, which is why monitoring and systemic control are important.

References