Colour contrast sensitivity thresholds along the tritan axis in patients with different stages of retinopathy
| Diabetic retinopathy level | Controls | Level 1 | Level 2 | Level 3 | |
| Number | 25 | 20 | 27 | 12 | |
| Threshold (%) | 7.1 (1.7) | 7.3 (1.9) | 8.1 (2.1) | 10.1 (3.0) | p = 0.020 |
↵According to Modified Airlie House Classification, for definition see Table 1.