Table 2.

The Distribution of Spherical Equivalent Among Different Birth Month Blocks in Grade 2 and Grade 3 at 2019 Visit

	Grade 2				Grade 3
	May to Aug 2012	Jan to Apr 2012	Sep to Dec 2011		May to Aug 2011	Jan to Apr 2011	Sep to Dec 2010
	Block Youngest	Block Middle	Block Oldest	P	Block Youngest	Block Middle	Block Oldest	P
Sample size	452	364	320	—	309	322	389	—
Gender				0.027*				0.326*
Male	262	177	168		160	184	204
Female	190	187	152		149	138	185
Mean age	7.42 ± 0.16	7.76 ± 0.16	8.08 ± 0.14	<0.001†	8.41 ± 0.11	8.76 ± 0.10	9.08 ± 0.11	<0.001†
SE	0.85 ± 0.76	0.88 ± 0.70	0.83 ± 0.64	0.632†	0.60 ± 0.82	0.57 ± 0.86	0.60 ± 0.88	0.902†

^*χ² was used.

^†One way analysis of variance was used.