Ever wonder where those famous “EDTRS letters” come from? The Early Treatment Diabetic Retinopathy Study (ETDRS) explored the role of focal laser coagulation, panretinal photocoagulation (PRP), and aspirin use for the treatment of non-proliferative diabetic retinopathy (NPDR) and early proliferative diabetic retinopathy (PDR). A total of 3,711 patients were included in ETDRS and randomized into two cohorts according to aspirin use (aspirin, 650 mg/day, n = 1,856; placebo, n = 1855). For each patient, each eye was assigned to early or deferred photocoagulation. The cohort of early photocoagulation eyes was further subdivided according to timing of focal and panretinal/scatter photocoagulation. Photocoagulation in deferred eyes was initiated upon detection of high-risk PDR.
Overall, the ETDRS demonstrated that early focal photocoagulation can avert vision loss related to diabetic macular edema. PRP is beneficial for patients with PDR or severe NPDR, but the risks outweigh the benefits for patients with mild or moderate NPDR. This study further laid the groundwork for many future Diabetic Retinopathy and other retina studies.
- Defined grading criteria for NPDR (see linked study with images)
- Early focal photocoagulation reduced the risk of vision loss from diabetic macular edema (ETDRS Report Number 1, 9)
- PRP decreased the risk of severe vision loss in patients with proliferative or severe non-proliferative diabetic retinopathy, but should be withheld in those with moderate or mild nonproliferative diabetic retinopathy due to adverse effects on visual field and acuity (ETDRS Report Number 9)
- Aspirin did not alter the disease course of diabetic retinopathy. Furthermore, aspirin use was not associated with adverse ocular events, including vitreous or preretinal hemorrhage. (ETDRS Report Number 8, 19, 20)