From the Guidelines
Diabetic retinopathy is classified into non-proliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR) based on specific clinical findings, with NPDR characterized by microaneurysms, dot and blot hemorrhages, hard exudates, cotton wool spots, venous beading, and intraretinal microvascular abnormalities (IRMA), and PDR representing disease progression with neovascularization, as stated in the most recent guidelines 1.
Key Characteristics of NPDR and PDR
- NPDR is further categorized as mild (only microaneurysms), moderate (more than just microaneurysms but less than severe), or severe (any of the "4-2-1 rule": extensive hemorrhages in 4 quadrants, venous beading in 2+ quadrants, or IRMA in 1+ quadrant) 1.
- PDR criteria include neovascularization of the disc (NVD), neovascularization elsewhere (NVE), vitreous hemorrhage, or tractional retinal detachment, as outlined in the guidelines 1.
Importance of Distinction
- The distinction between NPDR and PDR is crucial because PDR carries a higher risk of vision loss and requires more aggressive treatment, typically with panretinal photocoagulation laser therapy or anti-VEGF injections, while NPDR may be monitored or treated depending on severity and presence of diabetic macular edema, as recommended by the guidelines 1.
Treatment and Management
- Prompt referral to an ophthalmologist is recommended for patients with any level of diabetic macular edema, moderate or worse nonproliferative diabetic retinopathy, or any proliferative diabetic retinopathy, as stated in the guidelines 1.
- Panretinal laser photocoagulation therapy is indicated to reduce the risk of vision loss in patients with high-risk proliferative diabetic retinopathy and, in some cases, severe nonproliferative diabetic retinopathy, as recommended by the guidelines 1.
- Intravitreous injections of anti–vascular endothelial growth factor are a reasonable alternative to traditional panretinal laser photocoagulation for some patients with proliferative diabetic retinopathy and also reduce the risk of vision loss in these patients, as stated in the guidelines 1.
From the Research
Criteria for Non-Proliferative Diabetic Retinopathy (NPDR) and Proliferative Diabetic Retinopathy (PDR)
The criteria for NPDR and PDR can be understood through the following points:
- NPDR is an early stage of diabetic retinopathy, which can be classified into mild, moderate, and severe based on the presence of retinal lesions such as haemorrhages, microaneurysms, and exudates 2.
- The Diabetic Retinopathy Severity Scale (DRSS) is used to measure the severity of diabetic retinopathy, and it has become a clinically relevant endpoint for clinical trials 3.
- For PDR, the standard of care is panretinal photocoagulation (PRP), which has been established by the Diabetic Retinopathy Study (DRS) and the Early Treatment Diabetic Retinopathy Study (ETDRS) 3.
- Anti-vascular endothelial growth factor (VEGF) treatment has been shown to be effective in regressing neovascularization and improving DRSS levels in patients with PDR 3.
- For NPDR, the standard of care has been a wait-and-watch approach, but recent studies have demonstrated that anti-VEGF treatment can improve the DRSS score in NPDR 3, 4.
- The therapeutic approach to NPDR may undergo a paradigm shift toward considering early intervention with intravitreal anti-VEGF injections, but the long-term results and duration of adherence to anti-VEGF therapy are not yet defined 4.
Classification of NPDR
NPDR can be classified into:
- Mild: characterized by the presence of microaneurysms and haemorrhages
- Moderate: characterized by the presence of microaneurysms, haemorrhages, and exudates
- Severe: characterized by the presence of extensive microaneurysms, haemorrhages, and exudates 2
Treatment Options for NPDR and PDR
Treatment options for NPDR and PDR include: