Diabetic retinopathy is the leading cause of blindness in the USA. It occurs in both insulin dependent and non-insulin dependent diabetes mellitus.
- There are 3 main categories:
- background or simple retinopathy - consists of microaneurysms, hemorrhages, exudates, and retinal edema
- pre-proliferative retinopathy - with cotton wool spots
- proliferative or malignant retinopathy - consists of newly formed vessels.
- Patients are usually asymptomatic at first, despite early signs of retinopathy (e.g., microaneurysms).
- Visual impairment occurs with the development of macular edema.
- Argon laser photocoagulation is the suggested treatment for the prevention of complications.
- Done for destruction of ischemic retina ≠ ablation of abnormal vessels
- Screening should be done annually
- Type 1 DM: within 5 years of the onset of disease
- Type 2 DM: at the time of diagnosis
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Nonproliferative retinopathy (NPDR) |
Proliferative retinopathy (PDR) |
Diabetic macular edema (DME) |
| Mechanism |
Retinal vessel microangiopathy → blood leaks → retinal hemorrhages |
Retinal vessel microangiopathy → chronic retinal hypoxia → abnormal proliferation of blood vessels → traction on retina → retinal detachment |
Retinal vessel microangiopathy → blood leaks → retinal hemorrhages → retinal infiltration with lipids and fluid → macular edema |
| Examination findings (dilated eye exam or retinal photography) |
- Microaneurysms |
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- Caliber changes in veins
- Intraretinal hemorrhage
- Hard exudates
- Retinal edema
- Cotton-wool spots
- Intraretinal microvascular abnormalities (IRMA) | - Findings of nonproliferative retinopathy are usually present
- Neovascularization is the hallmark of PDR
- Fibrovascular proliferation → vitreous hemorrhage, traction retinal detachment
- Rubeosis iridis → 2º glaucoma | - Clinically significant retinal thickening and edema involving the macula, associated hard exudates
- May occur in all stages of NPDR and PDR |
| Vision Loss | May result from macular edema | May result from vitreous hemorrhage, retinal detachment, or neovascular glaucoma | May lead to vision loss |
| Treatment | - Treatment of diabetes and underlying ASCVD risk factors
- Mild-to-moderate: observation only; reassess every 6–12 months
- Severe: Consider PRP or anti-VEGF therapy | - Treatment of diabetes and underlying ASCVD risk factors
- PRP (usually first-line) and/or anti-VEGF therapy | - Treatment of diabetes and underlying ASCVD risk factors
- PRP, focal and/or grid laser, and anti-VEGF therapy may be considered depending on severity. |
Nonproliferative diabetic retinopathy
Proliferative diabetic retinopathy
Neovascularization of the iris (rubeosis iridis)