| Birth weight (g) | ||||||
|---|---|---|---|---|---|---|
| ≤750 | 751–1000 | >1000 | ||||
| 1990 | 2000 | 1990 | 2000 | 1990 | 2000 | |
| No ROP (%) | 3 (23.1) | 2 (8.7) | 29 (47.5) | 23 (34.4) | 123 (66.1) | 136 (83.4) |
| Mild ROP (%) | 3 (23.1) | 4 (17.4) | 14 (23.0) | 22 (32.8) | 36 (19.4) | 20 (12.3) |
| Severe ROP (%) | 7 (53.8) | 17 (73.9) | 18 (29.5) | 22 (32.8) | 27 (14.5) | 7 (4.3) |
| Total ROP (%) | 10 (76.9) | 21 (91.3) | 32 (52.5) | 44 (65.6) | 63 (33.9) | 27 (16.6) |
| Totals | 13 | 23 | 61 | 67 | 186 | 163 |