Table 1.

Statistical sizes of human optic discs reported by the references.

ID	Ver. Dia./mm	Ver. Dia. Std./mm	Hor. Dia./mm	Hor. Dia. Std./mm	Notes
1	1.97	0.19	1.78	0.18	Color fundus images of 3918 normal subjects over 40 years old [28]
2	1.88	0.25	1.79	0.19	Color fundus images of 118 normal subjects [29]
3	1.88	0.19	1.71	0.20	Color fundus images of 475 subjects [30]
4	1.98	0.28	1.82	0.28	Color fundus images of 62 normal subjects [31]
5	1.82	0.16	1.59	0.17	OCT images of 110 young people [32]
6 *	1.84	——	1.84	——	Color fundus images of 4027 normal subjects, and only optic disc area is measured [33]
7 *	1.78	——	1.78	——	Clinical anatomy based on 14 people [34]
8 *	1.81	——	1.81	——	Color fundus images of 70 subjects [35]
9 *	1.76	——	1.76	——	Color fundus images of 5514 subjects over 55 years old [36]
10	1.96	0.20	1.84	0.20	Color fundus images of 122 subjects [37]
11 *	1.70	——	1.70	——	Color fundus images of 2634 subjects [38]
12	1.97	0.29	1.79	0.27	Color slides of 88 unselected optic discs [39]

* Note: these studies only provided areas of optic disc, and the vertical and horizontal diameters are approximately calculated from the areas.