Table 4. Definition of Glaucoma by the International Society of Geographical and Epidemiological Ophthalmology (ISGEO) and the Number of Subjects of the Beijing Eye Study in Each Category.

Category	Definition	Number of Eyes
Category 1	definition 1AVCDR ≥ 97.5th percentile + VFD	50
definition 1B	VCDR Asymmetry ≥ 97.5th Percentile + VFD	21
definition 1C	Rim Width ≤ 0.1VCDR + VFD	41
Category 2	definition 2AVCDR ≥ 99.5th percentile	42
definition 2B	VCDR Asymmetry ≥ 99.5th Percentile	20
Category 3	definition 3Visual acuity <3/60 + IOP>99.5th Percentile	16
	/ filtering surgery
Glaucoma	Total	138

VCDR: Vertical cup/disc ratio.

VFD: Visual field defect.

IOP: Intraocular pressure.

The total sum of subjects adds up to more than the real total number of glaucomatous eye, since there was an overlap between the categories or definitions within each category.