The characteristics of infants in the IVC and IVR groups
| IVC group | IVR group | T | χ2 | P value | |
| No of eyes/children | 60/30 | 60/30 | / | / | |
| Male/female | 16/14 | 17/13 | / | 0.07 | 0.795* |
| Single/ multiple | 22/8 | 26/4 | / | 1.67 | 0.196* |
| NB/CS | 16/14 | 20/10 | / | 1.11 | 0.292* |
| BW (g) | 1160±480 | 1089±400 | 0.59 | 0.558 | |
| GA (week) | 28.27±2.77 | 27.50±2.70 | 1.08 | 0.284 | |
| PMA at first treatment (week) | 35.26±1.91 | 36.08±2.25 | −1.52 | 0.133 |
*χ2 test. The remaining indices are the t-test.
BW, birth weight; CS, caesarean section; GA, gestational age; IVC, intravitreal injection of conbercept; IVR, intravitreal injection of ranibizumab; NB, natural birth; PMA, postmenstrual age.