Table 3 Progression and regression of diabetic retinopathy
From: Epidemiology of diabetic retinopathy, diabetic macular edema and related vision loss
| Author (Year) | Method of severity grading | Progression intervals | Criteria for progression or regression | Progression of DR (%) | Progression from NPDR to PDR (%) | Regression of DR (%) |
|---|---|---|---|---|---|---|
| Asia | ||||||
| Tam (2009) [60] | Concatenated ETDRS severity of both eyes, with 11 levels | Cumulative at 4 years | 2-step | 34.7 | 9.9 | 13.2 |
| Song (2011) [61] | Eye with worse ETDRS severity | Cumulative at 4 years | 1-step | 6.6 | Not investigated | 45.8 |
| Kawasaki (2011) [62] | Mild DR to at least severe NPDR according to ETDRS | Cumulative at 8 years | N/A | N/A | 15.9 | Not investigated |
| Europe | ||||||
| Jones (2012) [52] | Eye with worse ETDRS severity | Cumulative at 5 years | Not stated | Data irretrievable | 6.1 | Not investigated |
| Cumulative at 10 years | 9.6 | |||||
| Broe (2014) [45] | Eye with worse ETDRS severity | Cumulative at 16 years | 2-step | 64.1 | 31.0 | 0 |
| North America | ||||||
| Tudor (1998) [53] | Eye with worse ETDRS severity | Cumulative at 4 years | 2-step | 24.1 | Not investigated | 13.3 |
| Varma (2010) [54] | Concatenated ETDRS severity of both eyes, with 15 levels | Cumulative at 4 years | 2-step | 38.9 | 5.3 | 14.0 |
| Klein (2008) [44] | Concatenated ETDRS severity of both eyes, with 15 levels | Between 0 to 4 years | 2-step | 13.5 annually | 2.5 annually | 3.0 annually |
| Between 4 to 10 years | 13.0 annually | 4.0 annually | 0.8 annually | |||
| Between 10 to 14 years | 12.0 annually | 2.5 annually | 0.4 annually | |||
| Between 14 to 25 years | 2.4 annually | 1.5 annually | 0.4 annually | |||
| Cumulative at 25 years | 83.1 | 42.0 | 17.8 | |||
| Oceania | ||||||
| Cikamatana (2007) [56] | Concatenated ETDRS severity of both eyes, with 15 levels | Cumulative at 5 years | 1-step | 25.9 | 4.1 | Not reported |
| Others | ||||||
| Leske (2006) [57] | Mild or moderate DR to at least severe NPDR according to ETDRS | Cumulative at 9 years | N/A | N/A | 8.2 | Not investigated |
| Tapp (2006) [58] | Mild or moderate DR to at least severe NPDR according to ETDRS | Cumulative at 6 years | N/A | 27.7 | 5.2 | Not investigated |