Table 1. Characteristics of cohorts with variable ROP severities.

Point of comparison	Worse grade ROP		Low grade ROP (80 infants)	No ROP (440 infants)	P
	Type 1 (16 infants)	Type 2 (24 infants)
Gender					0.661
Male	8 (50.0)	8 (33.3)	40 (50.0)	230 (52.3)
Female	8 (50.0)	16 (66.7)	40 (50.0)	210 (47.7)
GA (wk±SD)	28.0±1.2	31.5±1.1	30.9±1.8	31.9±1.7	<0.001a
Birth weight (g, mean±SD)	965.11±58.80	1105±134.03	1207±291.81	1217.96±242.81	<0.001a
ROP stage					<0.001a
0	0	0	6 (7.5)	440 (100.0)
1	0	0	50 (62.5)	0
2	8 (50.0)	0	24 (30.0)	0
3	8 (50.0)	24 (100.0)	0	0
ROP zone					<0.001a
0	0	0	0	40 (9.1)
I	8 (50.0)	0	0	0
II	8 (50.0)	24 (100.0)	58 (72.5)	20 (4.5)
III	0	0	22 (27.5)	380 (86.4)
Plus					<0.001a
No	0	24 (100.0)	72 (90.0)	440 (100.0)
Yes	16 (100.0)	0	8 (10.0)	0

ROP: Retinopathy of prematurity. ^aStatistically significant difference.

n (%)