Treatment of Proliferative Diabetic Retinopathy
Patients with proliferative diabetic retinopathy (PDR) should be promptly referred to an ophthalmologist experienced in diabetic retinopathy management, with treatment options including panretinal laser photocoagulation as traditional standard therapy or intravitreal anti-VEGF injections as an effective alternative. 1
Understanding Proliferative Diabetic Retinopathy
Proliferative diabetic retinopathy (PDR) is characterized by:
- Abnormal growth of new retinal blood vessels (neovascularization)
- Potential vitreous/preretinal hemorrhage
- Risk of severe vision loss if untreated
- Development after progression from non-proliferative stages 2
First-Line Treatment Options
Panretinal Laser Photocoagulation (PRP)
- Primary indication: High-risk PDR and some cases of severe non-proliferative diabetic retinopathy 1
- Efficacy: Reduces risk of severe vision loss from 15.9% to 6.4% in treated eyes 1
- Greatest benefit: In advanced baseline disease (disc neovascularization or vitreous hemorrhage) 1
- Advantages: Fewer visits required compared to anti-VEGF therapy, better for patients at risk of follow-up non-compliance 1
Anti-VEGF Intravitreal Injections
- Efficacy: Noninferior or superior visual acuity outcomes compared to PRP over 2 years 1
- FDA-approved agents: Aflibercept and ranibizumab for diabetic retinopathy 1, 3
- Advantages:
- Less peripheral visual field loss
- Fewer vitrectomy surgeries for secondary complications
- Lower risk of developing diabetic macular edema 1
- Disadvantages:
- Requires more frequent visits and treatments than PRP
- Risk of worse outcomes with lapses in treatment 1
Treatment Selection Algorithm
Immediate referral: Any patient with PDR should be promptly referred to an ophthalmologist 1
For high-risk PDR:
Consider PRP if:
- Patient has difficulty with regular follow-up
- Risk of treatment non-adherence
- Advanced disease with disc neovascularization or vitreous hemorrhage 1
Consider anti-VEGF if:
- Patient can maintain regular follow-up schedule
- Concern about peripheral visual field loss
- Concurrent diabetic macular edema 1
For PDR with concurrent diabetic macular edema:
- Anti-VEGF therapy is preferred first-line treatment, especially for central-involved diabetic macular edema 1
For vitreous hemorrhage due to PDR:
- If view allows, laser photocoagulation
- For non-clearing vitreous hemorrhage, pars plana vitrectomy with endolaser PRP 4
Special Considerations
Pregnancy
- PDR can worsen significantly during pregnancy (37% progression rate) 1
- Close monitoring required during pregnancy to prevent vision loss
- Laser photocoagulation can minimize vision loss during pregnancy 1
Concurrent Treatment
- Optimize glycemic control (target HbA1c <7%) to reduce risk of progression 1, 2
- Optimize blood pressure and lipid control 1
- Aspirin therapy for cardioprotection is not contraindicated in patients with retinopathy 1
Follow-up Recommendations
- PDR patients require follow-up less than 1 month after initial treatment 2
- More frequent monitoring required if:
- Retinopathy is progressing
- Vision is threatened
- Patient is pregnant 1
Treatment Efficacy
Recent evidence shows that ranibizumab alone (69.90%) and laser + ranibizumab (67.90%) provide the best visual score improvement in PDR patients 5. For central retinal thickness reduction, laser combined with ranibizumab (96.5%) shows the greatest improvement 5.
Complications and Pitfalls
- Anti-VEGF therapy: Risk of worse outcomes with lapses in treatment - critical to ensure patient adherence to follow-up schedule 1
- PRP: Higher overall incidence of adverse reactions (11.1%) compared to ranibizumab (10.6%) 5
- Rapid implementation of intensive glycemic control: May cause early worsening of retinopathy in patients with existing disease 1
Early detection and timely treatment are crucial to reduce visual morbidity and prevent blindness in patients with PDR 2.