Table 1 Correlation between disease severity levels according to the DRSS and ETDRS classification of DR
| Disease severity [16] | Findings observable upon dilated ophthalmoscopy [16] | ETDRS level equivalent [16] | Risk assessment [16] | Prevalence of vision-related difficulty [17] |
|---|---|---|---|---|
| No apparent retinopathy | No abnormalities | Level 10: DR absent |
Functional burden: 20.2% Reading: 11.7% Noticing objects to the side: 4.4% | |
| Mild NPDR | Microaneurysms only | Level 20: Very mild NPDR |
Functional burden: 20.4% Reading: 8.5% Noticing objects to the side: 2.8% | |
| Moderate NPDR | More than just microaneurysms but less than severe NPDR | Levels 35, 43: Mild, moderate NPDR less than 4:2:1 |
One-year risk for early PDR: 5.4–11.9% One-year high-risk PDR: 1.2–3.6% | |
| Level 47: Moderately severe NPDR less than 4:2:1 |
One-year risk for early PDR: 26.3% One-year high-risk PDR: 8.1% | |||
| Severe NPDR |
No signs of PR but with any of the following: Extensive (> 20) intraretinal hemorrhages in each of the 4 quadrants Definite venous beading in ≥ 2 quadrants Prominent IRMA in ≥ 1 quadrant | Levels 53A–53E: Severe to very severe NPDR, 4:2:1 rule |
One-year risk for early PDR: 50.2% (severe NPDR) One-year high-risk PDR: 14.6% (severe NPDR)–45.0% (very severe NPDR) |
Functional burden: 48.5% Reading: 33.3% Noticing objects to the side: 14.5% |
| PDR |
≥ 1 of the following: Neovascularization Vitreous/preretinal hemorrhage | Levels 61, 65, 71, 75, 81, 85: PDR, high-risk PDR, very severe, or advanced PDR | ||
| Ungradable | Level 90: Cannot grade, even sufficiently for level 81 or 85 |