How can diabetic retinopathy be prevented?

How to Prevent Diabetic Retinopathy

The most effective prevention strategy is achieving near-normoglycemic control (HbA1c <7%), combined with blood pressure control to <130/80 mmHg and lipid optimization, which together reduce the risk of developing diabetic retinopathy by approximately 67% and slow progression by 33%. 1, 2, 3

Glycemic Control: The Foundation

Target HbA1c <7% through intensive diabetes management to prevent or delay the onset of diabetic retinopathy. 1 Large prospective randomized studies have definitively shown that intensive glycemic control prevents and delays both the onset and progression of diabetic retinopathy. 1

• Intensive glycemic control reduces retinopathy progression by approximately 33% compared to standard therapy. 3
• The protective effect is strongest when initiated early in the disease course. 4
• Caution: Avoid rapid reductions in HbA1c when intensifying glucose-lowering therapies, as this can cause initial worsening of retinopathy (though this risk is minimal in newly diagnosed patients). 2, 3

Blood Pressure Control: Critical Secondary Target

Maintain blood pressure <130/80 mmHg to reduce retinopathy risk and slow progression. 1, 2, 3 Hypertension is an established risk factor for macular edema and proliferative diabetic retinopathy. 1

• Lowering blood pressure decreases retinopathy progression, as demonstrated by the UKPDS trial. 1
• Tight blood pressure control provides clear benefits, though systolic targets <120 mmHg do not provide additional benefit beyond <130 mmHg. 1, 2
• ACE inhibitors or ARBs are preferred first-line agents for patients with diabetes and hypertension, especially when retinopathy is present. 2

Lipid Management: The Third Pillar

Optimize serum lipid control to reduce retinopathy risk and slow progression. 1, 2

• Dyslipidemia is associated with increased retinopathy risk. 1
• Fenofibrate combined with statin therapy reduces retinopathy progression rates from 10.2% to 6.5% at 4 years (40% relative risk reduction). 4
• Fenofibrate may be particularly beneficial in patients with very mild nonproliferative diabetic retinopathy. 2

Screening Protocol: Early Detection Saves Vision

The timing of initial screening differs critically by diabetes type:

Type 1 Diabetes:

• Initial dilated comprehensive eye examination within 5 years after diabetes onset. 1, 5
• Rationale: Retinopathy takes at least 5 years to develop after onset of hyperglycemia. 1

Type 2 Diabetes:

• Initial dilated comprehensive eye examination at the time of diagnosis. 1, 2
• Rationale: Duration of hyperglycemia before diagnosis is unknown, and retinopathy may already be present. 1

Follow-up Screening:

• Annual dilated retinal examinations if any level of retinopathy is present. 1
• Screening every 1-2 years may be acceptable if no retinopathy is found for one or more annual exams AND glycemia is well controlled. 1
• More frequent examinations are required if retinopathy is progressing or sight-threatening. 1

Special Populations

Pregnancy in Type 1 or Type 2 Diabetes:

• Eye examinations should occur before pregnancy or in the first trimester. 1
• Monitor every trimester and for 1 year postpartum, as pregnancy may aggravate retinopathy and threaten vision, especially with poor glycemic control at conception. 1
• Laser photocoagulation can minimize vision loss risk during pregnancy. 1

Youth with Type 2 Diabetes:

• Screening for retinopathy should be performed by dilated fundoscopy at or soon after diagnosis and annually thereafter. 1
• Optimizing glycemia is recommended to decrease risk or slow progression. 1

Associated Risk Factors to Address

Diabetic nephropathy is strongly associated with retinopathy and should be monitored and treated aggressively. 1, 2 The presence of nephropathy increases retinopathy risk. 1

• Screen for microalbuminuria annually starting at diagnosis in type 2 diabetes and after 5 years in type 1 diabetes. 1
• Use ACE inhibitors or ARBs for treatment of albuminuria, which provides dual benefit for both kidney and eye protection. 1, 2

Common Pitfalls to Avoid

• Do not discontinue aspirin therapy due to concerns about retinal hemorrhage—retinopathy is not a contraindication to aspirin for cardioprotection, as aspirin does not increase the risk of retinal hemorrhage. 1, 2
• Do not delay screening in type 2 diabetes—examination should occur at diagnosis, not years later. 1
• Do not assume good glycemic control eliminates the need for screening—annual examinations remain necessary even with optimal control. 1

Emerging Considerations

Diabetic retinopathy is now recognized as an inflammatory, neurovascular complication with neuronal injury preceding clinical microvascular damage. 6 This emerging understanding points to neuroprotection as a potential future therapeutic strategy, though current prevention remains focused on the established triad of glycemic, blood pressure, and lipid control. 7, 6